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All volcanoes share the same basic features. First, mantle rock melts. The molten rock collects in magma chambers that can be 160 kilometers (100 miles) beneath the surface. As the rock heats, it expands. The hot rock is less dense than the surrounding rock. The magma rises toward the surface through cracks in the crust. A volcanic eruption occurs when the magma reaches the surface. Lava can reach the surface gently or explosively. Eruptions can be explosive or non-explosive. Only rarely do gentle and explosive eruptions happen in the same volcano. An explosive eruption produces huge clouds of volcanic ash. Chunks of the volcano fly high into the atmosphere. Explosive eruptions can be 10,000 times as powerful as an atomic bomb (Figure 8.6). Hot magma beneath the surface mixes with water. This forms gases. The gas pressure grows until it must be released. The volcano erupts in an enormous explosion. Ash and particles shoot many kilometers into the sky. The material may form a mushroom cloud, just like a nuclear explosion. Hot fragments of rock, called pyroclasts, fly up into the air at very high speeds. The pyroclasts cool in the atmosphere. Some ash may stay in the atmosphere for years. The ash may block out sunlight. This changes weather patterns and affects the temperature of the Earth. For a year or two after a large eruption, sunsets may be especially beautiful worldwide. Volcanic gases can form poisonous, invisible clouds. The poisonous gases may be toxic close to the eruption. The gases may cause environmental problems like acid rain and ozone destruction. Mt St. Helens was not a very large eruption for the Cascades. Mt. Mazama blew itself apart in an eruption about 42 times more powerful than Mount St. Helens in 1980. Today all that remains of that huge stratovolcano is Crater Lake (Figure 8.18). Some volcanic eruptions are non-explosive (Figure 8.7). This happens when there is little or no gas. The lava is thin, fluid and runny. It flows over the ground like a river. People generally have a lot of warning before a lava flow like this reaches them, so non-explosive eruptions are much less deadly. They may still be destructive to property, though. Even when we know that a lava flow is approaching, there are few ways of stopping it! Great volcanic explosions and glowing red rivers of lava are fascinating. All igneous rock comes from magma or lava. Remember that magma is molten rock that is below Earths surface. Lava is molten rock at Earths surface. Magma forms deep beneath the Earths surface. Rock melts below the surface under tremendous pressure and high temperatures. Molten rock flows like taffy or hot wax. Most magmas are formed at temperatures between 600o C and 1300o C (Figure 8.8). Magma collects in magma chambers beneath Earths surface. Magma chambers are located where the heat and pressure are great enough to melt rock. These locations are at divergent or convergent plate boundaries or at hotpots. The chemistry of a magma determines the type of igneous rock it forms. The chemistry also determines how the magma moves. Thicker magmas tend to stay below the surface or erupt explosively. When magma is fluid and runny, it often reaches the surface by flowing out in rivers of lava. The way lava flows depends on what it is made of. Thick lava doesnt flow easily. It may block the vent of a volcano. If the lava traps a lot of gas, the pressure builds up. After the pressure becomes greater and greater, the volcano finally explodes. Ash and pyroclasts shoot up into the air. Pumice, with small holes in solid rock, shows where gas bubbles were when the rock was still molten. Fluid lava flows down mountainsides. The rock that the flow becomes depends on which type of lava it is and where it cools. The three types of flows are aa, pahoehoe, and pillow lava. Aa Lava Aa lava is the thickest of the non-explosive lavas. Aa forms a thick and brittle crust, which is torn into rough, rubbly pieces. The solidified surface is angular, jagged and sharp. Aa can
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lava that enters water
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"pillow lava"
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All volcanoes share the same basic features. First, mantle rock melts. The molten rock collects in magma chambers that can be 160 kilometers (100 miles) beneath the surface. As the rock heats, it expands. The hot rock is less dense than the surrounding rock. The magma rises toward the surface through cracks in the crust. A volcanic eruption occurs when the magma reaches the surface. Lava can reach the surface gently or explosively. Eruptions can be explosive or non-explosive. Only rarely do gentle and explosive eruptions happen in the same volcano. An explosive eruption produces huge clouds of volcanic ash. Chunks of the volcano fly high into the atmosphere. Explosive eruptions can be 10,000 times as powerful as an atomic bomb (Figure 8.6). Hot magma beneath the surface mixes with water. This forms gases. The gas pressure grows until it must be released. The volcano erupts in an enormous explosion. Ash and particles shoot many kilometers into the sky. The material may form a mushroom cloud, just like a nuclear explosion. Hot fragments of rock, called pyroclasts, fly up into the air at very high speeds. The pyroclasts cool in the atmosphere. Some ash may stay in the atmosphere for years. The ash may block out sunlight. This changes weather patterns and affects the temperature of the Earth. For a year or two after a large eruption, sunsets may be especially beautiful worldwide. Volcanic gases can form poisonous, invisible clouds. The poisonous gases may be toxic close to the eruption. The gases may cause environmental problems like acid rain and ozone destruction. Mt St. Helens was not a very large eruption for the Cascades. Mt. Mazama blew itself apart in an eruption about 42 times more powerful than Mount St. Helens in 1980. Today all that remains of that huge stratovolcano is Crater Lake (Figure 8.18). Some volcanic eruptions are non-explosive (Figure 8.7). This happens when there is little or no gas. The lava is thin, fluid and runny. It flows over the ground like a river. People generally have a lot of warning before a lava flow like this reaches them, so non-explosive eruptions are much less deadly. They may still be destructive to property, though. Even when we know that a lava flow is approaching, there are few ways of stopping it! Great volcanic explosions and glowing red rivers of lava are fascinating. All igneous rock comes from magma or lava. Remember that magma is molten rock that is below Earths surface. Lava is molten rock at Earths surface. Magma forms deep beneath the Earths surface. Rock melts below the surface under tremendous pressure and high temperatures. Molten rock flows like taffy or hot wax. Most magmas are formed at temperatures between 600o C and 1300o C (Figure 8.8). Magma collects in magma chambers beneath Earths surface. Magma chambers are located where the heat and pressure are great enough to melt rock. These locations are at divergent or convergent plate boundaries or at hotpots. The chemistry of a magma determines the type of igneous rock it forms. The chemistry also determines how the magma moves. Thicker magmas tend to stay below the surface or erupt explosively. When magma is fluid and runny, it often reaches the surface by flowing out in rivers of lava. The way lava flows depends on what it is made of. Thick lava doesnt flow easily. It may block the vent of a volcano. If the lava traps a lot of gas, the pressure builds up. After the pressure becomes greater and greater, the volcano finally explodes. Ash and pyroclasts shoot up into the air. Pumice, with small holes in solid rock, shows where gas bubbles were when the rock was still molten. Fluid lava flows down mountainsides. The rock that the flow becomes depends on which type of lava it is and where it cools. The three types of flows are aa, pahoehoe, and pillow lava. Aa Lava Aa lava is the thickest of the non-explosive lavas. Aa forms a thick and brittle crust, which is torn into rough, rubbly pieces. The solidified surface is angular, jagged and sharp. Aa can
|
any release of magma onto Earths surface
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"volcanic eruption"
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Did you ever notice when you get into a bathtub of water that the level of the water rises? More than 2000 years ago, a Greek mathematician named Archimedes noticed the same thing. He observed that both a body and the water in a tub cant occupy the same space at the same time. As a result, some of the water is displaced, or moved out of the way. How much water is displaced? Archimedes determined that the volume of displaced water equals the volume of the submerged object. So more water is displaced by a bigger body than a smaller one. Q: If you jump into swimming pool, how much water does your body displace? A: The water displaced by your body is equal to your bodys volume. Depending on your size, this volume might be about 0.07 m3 . Objects such as ships may float in a fluid like water because of buoyant force. This is an upward force that a fluid exerts on any object that is placed in it. Archimedes discovered that the buoyant force acting on an object equals the weight of the fluid displaced by the object. This is known as Archimedes law (or Archimedes principle). Archimedes law explains why some objects float in fluids even though they are very heavy. It all depends on how much fluid they displace. The cruise ship pictured in the opening image is extremely heavy, yet it stays afloat. If a steel ball with the same weight as the ship were placed in water, it would sink to the bottom. This is modeled in the Figure 1.1. The reason the ball sinks is that its shape is very compact, so it displaces relatively little water. The volume of water displaced by the steel ball weighs less than the ball itself, so the buoyant force is not as great as the force of gravity pulling down on the ball. Thus, the ball sinks. Now look at the ships hull in the Figure 1.1. Its shape causes the ship to displace much more water than the ball. In fact, the weight of the displaced water is greater than the weight of the ship. As a result, the buoyant force is greater than the force of gravity acting on the ship, so the ship floats. Q: Why might you be more likely to float in water if you stretch out your body rather than curl up into a ball? A: You would displace more water by stretching out your body, so there would be more buoyant force acting on it. Therefore, you would be more likely to float in this position.
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archimedes determined that the volume of water displaced by an object placed in the water is equal to the objects
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Human population growth over the past 10,000 years has been tremendous (Figure 1.1). The entire human popula- tion was estimated to be 5 million in 8000 B.C. 300 million in A.D. 1 1 billion in 1802 3 billion in 1961 7 billion in 2011 As the human population continues to grow, different factors limit population in different parts of the world. What might be a limiting factor for human population in a particular location? Space, clean air, clean water, and food to feed everyone are limiting in some locations. Not only has the population increased, but the rate of population growth has increased (Figure 1.2). The population was estimated to reach 7 billion in 2012, but it did so in 2011, just 12 years after reaching 6 billion. Human population from 10,000 BC through 2000 AD, showing the exponential increase in human population that has occurred in the last few centuries. The amount of time between the addition of each one billion people to the planets population, including speculation about the future. Although population continues to grow rapidly, the rate that the growth rate is increasing has declined. Still, a recent estimate by the United Nations estimates that 10.1 billion people will be sharing this planet by the end of the century. The total added will be about 3 billion people, which is more than were even in existence as recently as 1960.
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human population reached its first billion in which year?
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"1802"
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Human population growth over the past 10,000 years has been tremendous (Figure 1.1). The entire human popula- tion was estimated to be 5 million in 8000 B.C. 300 million in A.D. 1 1 billion in 1802 3 billion in 1961 7 billion in 2011 As the human population continues to grow, different factors limit population in different parts of the world. What might be a limiting factor for human population in a particular location? Space, clean air, clean water, and food to feed everyone are limiting in some locations. Not only has the population increased, but the rate of population growth has increased (Figure 1.2). The population was estimated to reach 7 billion in 2012, but it did so in 2011, just 12 years after reaching 6 billion. Human population from 10,000 BC through 2000 AD, showing the exponential increase in human population that has occurred in the last few centuries. The amount of time between the addition of each one billion people to the planets population, including speculation about the future. Although population continues to grow rapidly, the rate that the growth rate is increasing has declined. Still, a recent estimate by the United Nations estimates that 10.1 billion people will be sharing this planet by the end of the century. The total added will be about 3 billion people, which is more than were even in existence as recently as 1960.
|
in 2011, the human population increased to ___________.
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"7 billion"
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As was discussed in previous concepts, both infectious and noninfectious diseases of the reproductive system can be very serious. But there are ways to keep your reproductive system healthy. What can you do to keep your reproductive system healthy? You can start by making the right choices for overall good health. To be as healthy as you can be, you should: Eat a balanced diet that is high in fiber and low in fat. Drink plenty of water. Get regular exercise. Maintain a healthy weight. Get enough sleep. Avoid using tobacco, alcohol, or other drugs. Manage stress in healthy ways. Keeping your genitals clean is also very important. A daily shower or bath is all that it takes. Females do not need to use special feminine hygiene products. In fact, using them may do more harm than good because they can irritate the vagina or other reproductive structures. You should also avoid other behaviors that can put you at risk. Do not get into contact with another persons blood or other body fluids. For example, never get a tattoo or piercing unless you are sure that the needles have not been used before. This is one of the most important ways to prevent an STI. Of course, the only way to be fully protected against STIs is to refrain from sexual activity. If you are a boy, you should always wear a protective cup when you play contact sports. Contact sports include football, boxing, and hockey. Wearing a cup will help protect the testes from injury. You should also do a monthly self-exam to check for cancer of the testes. If you are a girl and use tampons, be sure to change them every four to six hours. Leaving tampons in for too long can put you at risk of toxic shock syndrome. This is a serious condition. Signs and symptoms of toxic shock syndrome develop suddenly, and the disease can be fatal. The disease involves fever, shock, and problems with the function of several body organs. Girls should also get in the habit of doing a monthly self-exam to check for breast cancer. Although breast cancer is rare in teens, its a good idea to start doing the exam when you are young. It will help you get to know what is normal for you.
|
a balanced diet is
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As was discussed in previous concepts, both infectious and noninfectious diseases of the reproductive system can be very serious. But there are ways to keep your reproductive system healthy. What can you do to keep your reproductive system healthy? You can start by making the right choices for overall good health. To be as healthy as you can be, you should: Eat a balanced diet that is high in fiber and low in fat. Drink plenty of water. Get regular exercise. Maintain a healthy weight. Get enough sleep. Avoid using tobacco, alcohol, or other drugs. Manage stress in healthy ways. Keeping your genitals clean is also very important. A daily shower or bath is all that it takes. Females do not need to use special feminine hygiene products. In fact, using them may do more harm than good because they can irritate the vagina or other reproductive structures. You should also avoid other behaviors that can put you at risk. Do not get into contact with another persons blood or other body fluids. For example, never get a tattoo or piercing unless you are sure that the needles have not been used before. This is one of the most important ways to prevent an STI. Of course, the only way to be fully protected against STIs is to refrain from sexual activity. If you are a boy, you should always wear a protective cup when you play contact sports. Contact sports include football, boxing, and hockey. Wearing a cup will help protect the testes from injury. You should also do a monthly self-exam to check for cancer of the testes. If you are a girl and use tampons, be sure to change them every four to six hours. Leaving tampons in for too long can put you at risk of toxic shock syndrome. This is a serious condition. Signs and symptoms of toxic shock syndrome develop suddenly, and the disease can be fatal. The disease involves fever, shock, and problems with the function of several body organs. Girls should also get in the habit of doing a monthly self-exam to check for breast cancer. Although breast cancer is rare in teens, its a good idea to start doing the exam when you are young. It will help you get to know what is normal for you.
|
girls should perform monthly self-exams to check for
|
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"breast cancer."
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As was discussed in previous concepts, both infectious and noninfectious diseases of the reproductive system can be very serious. But there are ways to keep your reproductive system healthy. What can you do to keep your reproductive system healthy? You can start by making the right choices for overall good health. To be as healthy as you can be, you should: Eat a balanced diet that is high in fiber and low in fat. Drink plenty of water. Get regular exercise. Maintain a healthy weight. Get enough sleep. Avoid using tobacco, alcohol, or other drugs. Manage stress in healthy ways. Keeping your genitals clean is also very important. A daily shower or bath is all that it takes. Females do not need to use special feminine hygiene products. In fact, using them may do more harm than good because they can irritate the vagina or other reproductive structures. You should also avoid other behaviors that can put you at risk. Do not get into contact with another persons blood or other body fluids. For example, never get a tattoo or piercing unless you are sure that the needles have not been used before. This is one of the most important ways to prevent an STI. Of course, the only way to be fully protected against STIs is to refrain from sexual activity. If you are a boy, you should always wear a protective cup when you play contact sports. Contact sports include football, boxing, and hockey. Wearing a cup will help protect the testes from injury. You should also do a monthly self-exam to check for cancer of the testes. If you are a girl and use tampons, be sure to change them every four to six hours. Leaving tampons in for too long can put you at risk of toxic shock syndrome. This is a serious condition. Signs and symptoms of toxic shock syndrome develop suddenly, and the disease can be fatal. The disease involves fever, shock, and problems with the function of several body organs. Girls should also get in the habit of doing a monthly self-exam to check for breast cancer. Although breast cancer is rare in teens, its a good idea to start doing the exam when you are young. It will help you get to know what is normal for you.
|
it is recommended that boys were a protective cup while playing
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"football, boxing, and hockey."
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What do temperature, clouds, winds, and rain have in common? They are all part of weather. Weather refers to the conditions of the atmosphere at a given time and place. Weather occurs because of unequal heating of the atmosphere. The source of heat is the Sun. The general principles behind weather can be stated simply: The Sun heats Earths surface more in some places than others. Where it is warm, heat from the Sun warms the air close to the surface. If there is water at the surface, it may cause some of the water to evaporate. Warm air is less dense, so it rises. When this happens, more dense air flows in to take its place. The flowing surface air is wind. The rising air cools as it goes higher in the atmosphere. If it is moist, the water vapor may condense. Clouds may form, and precipitation may fall. The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. Humidity usually refers to relative humidity. This is the percent of water vapor in the air relative to the total amount the air can hold. How much water vapor can the air hold? That depends on temperature. Warm air can hold more water vapor than cool air. You can see this in Figure 16.1. People often say, its not the heat but the humidity. Humidity can make a hot day feel even hotter. When sweat evaporates, it cools your body. But sweat cant evaporate when the air already contains as much water vapor as it can hold. The heat index is a measure of what the temperature feels like because of the humidity. You can see the heat index in Figure 16.2. Youve probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point. If this temperature is below freezing, ice crystals of frost form instead of dew. As you can see in Figure 16.1, the dew point occurs at 100 percent relative humidity. Can you explain why? Clouds form when air in the atmosphere reaches the dew point. Clouds may form anywhere in the troposphere. Clouds that form on the ground are called fog. Clouds form when water vapor condenses around particles in the air. The particles are specks of matter, such as dust or smoke. Billions of these tiny water droplets come together to make up a cloud. If the air is very cold, ice crystals form instead of liquid water. Clouds are classified on the basis of where and how they form. Three main types of clouds are cirrus, stratus, and cumulus. Figure 16.3 shows these and other types of clouds. Cirrus clouds form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds dont usually produce precipitation, but they may be a sign that wet weather is coming. Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means rain. Cumulus clouds are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus. Clouds can affect the temperature on Earths surface. During the day, thick clouds block some of the Suns rays. This keeps the surface from heating up as much as it would on a clear day. At night, thick clouds prevent
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type of cloud that forms in low, horizontal layers
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What do temperature, clouds, winds, and rain have in common? They are all part of weather. Weather refers to the conditions of the atmosphere at a given time and place. Weather occurs because of unequal heating of the atmosphere. The source of heat is the Sun. The general principles behind weather can be stated simply: The Sun heats Earths surface more in some places than others. Where it is warm, heat from the Sun warms the air close to the surface. If there is water at the surface, it may cause some of the water to evaporate. Warm air is less dense, so it rises. When this happens, more dense air flows in to take its place. The flowing surface air is wind. The rising air cools as it goes higher in the atmosphere. If it is moist, the water vapor may condense. Clouds may form, and precipitation may fall. The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. Humidity usually refers to relative humidity. This is the percent of water vapor in the air relative to the total amount the air can hold. How much water vapor can the air hold? That depends on temperature. Warm air can hold more water vapor than cool air. You can see this in Figure 16.1. People often say, its not the heat but the humidity. Humidity can make a hot day feel even hotter. When sweat evaporates, it cools your body. But sweat cant evaporate when the air already contains as much water vapor as it can hold. The heat index is a measure of what the temperature feels like because of the humidity. You can see the heat index in Figure 16.2. Youve probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point. If this temperature is below freezing, ice crystals of frost form instead of dew. As you can see in Figure 16.1, the dew point occurs at 100 percent relative humidity. Can you explain why? Clouds form when air in the atmosphere reaches the dew point. Clouds may form anywhere in the troposphere. Clouds that form on the ground are called fog. Clouds form when water vapor condenses around particles in the air. The particles are specks of matter, such as dust or smoke. Billions of these tiny water droplets come together to make up a cloud. If the air is very cold, ice crystals form instead of liquid water. Clouds are classified on the basis of where and how they form. Three main types of clouds are cirrus, stratus, and cumulus. Figure 16.3 shows these and other types of clouds. Cirrus clouds form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds dont usually produce precipitation, but they may be a sign that wet weather is coming. Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means rain. Cumulus clouds are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus. Clouds can affect the temperature on Earths surface. During the day, thick clouds block some of the Suns rays. This keeps the surface from heating up as much as it would on a clear day. At night, thick clouds prevent
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type of cloud that is white and puffy
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What do temperature, clouds, winds, and rain have in common? They are all part of weather. Weather refers to the conditions of the atmosphere at a given time and place. Weather occurs because of unequal heating of the atmosphere. The source of heat is the Sun. The general principles behind weather can be stated simply: The Sun heats Earths surface more in some places than others. Where it is warm, heat from the Sun warms the air close to the surface. If there is water at the surface, it may cause some of the water to evaporate. Warm air is less dense, so it rises. When this happens, more dense air flows in to take its place. The flowing surface air is wind. The rising air cools as it goes higher in the atmosphere. If it is moist, the water vapor may condense. Clouds may form, and precipitation may fall. The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. Humidity usually refers to relative humidity. This is the percent of water vapor in the air relative to the total amount the air can hold. How much water vapor can the air hold? That depends on temperature. Warm air can hold more water vapor than cool air. You can see this in Figure 16.1. People often say, its not the heat but the humidity. Humidity can make a hot day feel even hotter. When sweat evaporates, it cools your body. But sweat cant evaporate when the air already contains as much water vapor as it can hold. The heat index is a measure of what the temperature feels like because of the humidity. You can see the heat index in Figure 16.2. Youve probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point. If this temperature is below freezing, ice crystals of frost form instead of dew. As you can see in Figure 16.1, the dew point occurs at 100 percent relative humidity. Can you explain why? Clouds form when air in the atmosphere reaches the dew point. Clouds may form anywhere in the troposphere. Clouds that form on the ground are called fog. Clouds form when water vapor condenses around particles in the air. The particles are specks of matter, such as dust or smoke. Billions of these tiny water droplets come together to make up a cloud. If the air is very cold, ice crystals form instead of liquid water. Clouds are classified on the basis of where and how they form. Three main types of clouds are cirrus, stratus, and cumulus. Figure 16.3 shows these and other types of clouds. Cirrus clouds form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds dont usually produce precipitation, but they may be a sign that wet weather is coming. Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means rain. Cumulus clouds are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus. Clouds can affect the temperature on Earths surface. During the day, thick clouds block some of the Suns rays. This keeps the surface from heating up as much as it would on a clear day. At night, thick clouds prevent
|
measure of what the temperature feels like because of humidity
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What do temperature, clouds, winds, and rain have in common? They are all part of weather. Weather refers to the conditions of the atmosphere at a given time and place. Weather occurs because of unequal heating of the atmosphere. The source of heat is the Sun. The general principles behind weather can be stated simply: The Sun heats Earths surface more in some places than others. Where it is warm, heat from the Sun warms the air close to the surface. If there is water at the surface, it may cause some of the water to evaporate. Warm air is less dense, so it rises. When this happens, more dense air flows in to take its place. The flowing surface air is wind. The rising air cools as it goes higher in the atmosphere. If it is moist, the water vapor may condense. Clouds may form, and precipitation may fall. The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. Humidity usually refers to relative humidity. This is the percent of water vapor in the air relative to the total amount the air can hold. How much water vapor can the air hold? That depends on temperature. Warm air can hold more water vapor than cool air. You can see this in Figure 16.1. People often say, its not the heat but the humidity. Humidity can make a hot day feel even hotter. When sweat evaporates, it cools your body. But sweat cant evaporate when the air already contains as much water vapor as it can hold. The heat index is a measure of what the temperature feels like because of the humidity. You can see the heat index in Figure 16.2. Youve probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point. If this temperature is below freezing, ice crystals of frost form instead of dew. As you can see in Figure 16.1, the dew point occurs at 100 percent relative humidity. Can you explain why? Clouds form when air in the atmosphere reaches the dew point. Clouds may form anywhere in the troposphere. Clouds that form on the ground are called fog. Clouds form when water vapor condenses around particles in the air. The particles are specks of matter, such as dust or smoke. Billions of these tiny water droplets come together to make up a cloud. If the air is very cold, ice crystals form instead of liquid water. Clouds are classified on the basis of where and how they form. Three main types of clouds are cirrus, stratus, and cumulus. Figure 16.3 shows these and other types of clouds. Cirrus clouds form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds dont usually produce precipitation, but they may be a sign that wet weather is coming. Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means rain. Cumulus clouds are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus. Clouds can affect the temperature on Earths surface. During the day, thick clouds block some of the Suns rays. This keeps the surface from heating up as much as it would on a clear day. At night, thick clouds prevent
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What do temperature, clouds, winds, and rain have in common? They are all part of weather. Weather refers to the conditions of the atmosphere at a given time and place. Weather occurs because of unequal heating of the atmosphere. The source of heat is the Sun. The general principles behind weather can be stated simply: The Sun heats Earths surface more in some places than others. Where it is warm, heat from the Sun warms the air close to the surface. If there is water at the surface, it may cause some of the water to evaporate. Warm air is less dense, so it rises. When this happens, more dense air flows in to take its place. The flowing surface air is wind. The rising air cools as it goes higher in the atmosphere. If it is moist, the water vapor may condense. Clouds may form, and precipitation may fall. The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. Humidity usually refers to relative humidity. This is the percent of water vapor in the air relative to the total amount the air can hold. How much water vapor can the air hold? That depends on temperature. Warm air can hold more water vapor than cool air. You can see this in Figure 16.1. People often say, its not the heat but the humidity. Humidity can make a hot day feel even hotter. When sweat evaporates, it cools your body. But sweat cant evaporate when the air already contains as much water vapor as it can hold. The heat index is a measure of what the temperature feels like because of the humidity. You can see the heat index in Figure 16.2. Youve probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point. If this temperature is below freezing, ice crystals of frost form instead of dew. As you can see in Figure 16.1, the dew point occurs at 100 percent relative humidity. Can you explain why? Clouds form when air in the atmosphere reaches the dew point. Clouds may form anywhere in the troposphere. Clouds that form on the ground are called fog. Clouds form when water vapor condenses around particles in the air. The particles are specks of matter, such as dust or smoke. Billions of these tiny water droplets come together to make up a cloud. If the air is very cold, ice crystals form instead of liquid water. Clouds are classified on the basis of where and how they form. Three main types of clouds are cirrus, stratus, and cumulus. Figure 16.3 shows these and other types of clouds. Cirrus clouds form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds dont usually produce precipitation, but they may be a sign that wet weather is coming. Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means rain. Cumulus clouds are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus. Clouds can affect the temperature on Earths surface. During the day, thick clouds block some of the Suns rays. This keeps the surface from heating up as much as it would on a clear day. At night, thick clouds prevent
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What do temperature, clouds, winds, and rain have in common? They are all part of weather. Weather refers to the conditions of the atmosphere at a given time and place. Weather occurs because of unequal heating of the atmosphere. The source of heat is the Sun. The general principles behind weather can be stated simply: The Sun heats Earths surface more in some places than others. Where it is warm, heat from the Sun warms the air close to the surface. If there is water at the surface, it may cause some of the water to evaporate. Warm air is less dense, so it rises. When this happens, more dense air flows in to take its place. The flowing surface air is wind. The rising air cools as it goes higher in the atmosphere. If it is moist, the water vapor may condense. Clouds may form, and precipitation may fall. The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. Humidity usually refers to relative humidity. This is the percent of water vapor in the air relative to the total amount the air can hold. How much water vapor can the air hold? That depends on temperature. Warm air can hold more water vapor than cool air. You can see this in Figure 16.1. People often say, its not the heat but the humidity. Humidity can make a hot day feel even hotter. When sweat evaporates, it cools your body. But sweat cant evaporate when the air already contains as much water vapor as it can hold. The heat index is a measure of what the temperature feels like because of the humidity. You can see the heat index in Figure 16.2. Youve probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point. If this temperature is below freezing, ice crystals of frost form instead of dew. As you can see in Figure 16.1, the dew point occurs at 100 percent relative humidity. Can you explain why? Clouds form when air in the atmosphere reaches the dew point. Clouds may form anywhere in the troposphere. Clouds that form on the ground are called fog. Clouds form when water vapor condenses around particles in the air. The particles are specks of matter, such as dust or smoke. Billions of these tiny water droplets come together to make up a cloud. If the air is very cold, ice crystals form instead of liquid water. Clouds are classified on the basis of where and how they form. Three main types of clouds are cirrus, stratus, and cumulus. Figure 16.3 shows these and other types of clouds. Cirrus clouds form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds dont usually produce precipitation, but they may be a sign that wet weather is coming. Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means rain. Cumulus clouds are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus. Clouds can affect the temperature on Earths surface. During the day, thick clouds block some of the Suns rays. This keeps the surface from heating up as much as it would on a clear day. At night, thick clouds prevent
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What do temperature, clouds, winds, and rain have in common? They are all part of weather. Weather refers to the conditions of the atmosphere at a given time and place. Weather occurs because of unequal heating of the atmosphere. The source of heat is the Sun. The general principles behind weather can be stated simply: The Sun heats Earths surface more in some places than others. Where it is warm, heat from the Sun warms the air close to the surface. If there is water at the surface, it may cause some of the water to evaporate. Warm air is less dense, so it rises. When this happens, more dense air flows in to take its place. The flowing surface air is wind. The rising air cools as it goes higher in the atmosphere. If it is moist, the water vapor may condense. Clouds may form, and precipitation may fall. The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. Humidity usually refers to relative humidity. This is the percent of water vapor in the air relative to the total amount the air can hold. How much water vapor can the air hold? That depends on temperature. Warm air can hold more water vapor than cool air. You can see this in Figure 16.1. People often say, its not the heat but the humidity. Humidity can make a hot day feel even hotter. When sweat evaporates, it cools your body. But sweat cant evaporate when the air already contains as much water vapor as it can hold. The heat index is a measure of what the temperature feels like because of the humidity. You can see the heat index in Figure 16.2. Youve probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point. If this temperature is below freezing, ice crystals of frost form instead of dew. As you can see in Figure 16.1, the dew point occurs at 100 percent relative humidity. Can you explain why? Clouds form when air in the atmosphere reaches the dew point. Clouds may form anywhere in the troposphere. Clouds that form on the ground are called fog. Clouds form when water vapor condenses around particles in the air. The particles are specks of matter, such as dust or smoke. Billions of these tiny water droplets come together to make up a cloud. If the air is very cold, ice crystals form instead of liquid water. Clouds are classified on the basis of where and how they form. Three main types of clouds are cirrus, stratus, and cumulus. Figure 16.3 shows these and other types of clouds. Cirrus clouds form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds dont usually produce precipitation, but they may be a sign that wet weather is coming. Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means rain. Cumulus clouds are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus. Clouds can affect the temperature on Earths surface. During the day, thick clouds block some of the Suns rays. This keeps the surface from heating up as much as it would on a clear day. At night, thick clouds prevent
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What do temperature, clouds, winds, and rain have in common? They are all part of weather. Weather refers to the conditions of the atmosphere at a given time and place. Weather occurs because of unequal heating of the atmosphere. The source of heat is the Sun. The general principles behind weather can be stated simply: The Sun heats Earths surface more in some places than others. Where it is warm, heat from the Sun warms the air close to the surface. If there is water at the surface, it may cause some of the water to evaporate. Warm air is less dense, so it rises. When this happens, more dense air flows in to take its place. The flowing surface air is wind. The rising air cools as it goes higher in the atmosphere. If it is moist, the water vapor may condense. Clouds may form, and precipitation may fall. The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. Humidity usually refers to relative humidity. This is the percent of water vapor in the air relative to the total amount the air can hold. How much water vapor can the air hold? That depends on temperature. Warm air can hold more water vapor than cool air. You can see this in Figure 16.1. People often say, its not the heat but the humidity. Humidity can make a hot day feel even hotter. When sweat evaporates, it cools your body. But sweat cant evaporate when the air already contains as much water vapor as it can hold. The heat index is a measure of what the temperature feels like because of the humidity. You can see the heat index in Figure 16.2. Youve probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point. If this temperature is below freezing, ice crystals of frost form instead of dew. As you can see in Figure 16.1, the dew point occurs at 100 percent relative humidity. Can you explain why? Clouds form when air in the atmosphere reaches the dew point. Clouds may form anywhere in the troposphere. Clouds that form on the ground are called fog. Clouds form when water vapor condenses around particles in the air. The particles are specks of matter, such as dust or smoke. Billions of these tiny water droplets come together to make up a cloud. If the air is very cold, ice crystals form instead of liquid water. Clouds are classified on the basis of where and how they form. Three main types of clouds are cirrus, stratus, and cumulus. Figure 16.3 shows these and other types of clouds. Cirrus clouds form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds dont usually produce precipitation, but they may be a sign that wet weather is coming. Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means rain. Cumulus clouds are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus. Clouds can affect the temperature on Earths surface. During the day, thick clouds block some of the Suns rays. This keeps the surface from heating up as much as it would on a clear day. At night, thick clouds prevent
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What do temperature, clouds, winds, and rain have in common? They are all part of weather. Weather refers to the conditions of the atmosphere at a given time and place. Weather occurs because of unequal heating of the atmosphere. The source of heat is the Sun. The general principles behind weather can be stated simply: The Sun heats Earths surface more in some places than others. Where it is warm, heat from the Sun warms the air close to the surface. If there is water at the surface, it may cause some of the water to evaporate. Warm air is less dense, so it rises. When this happens, more dense air flows in to take its place. The flowing surface air is wind. The rising air cools as it goes higher in the atmosphere. If it is moist, the water vapor may condense. Clouds may form, and precipitation may fall. The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation. Humidity usually refers to relative humidity. This is the percent of water vapor in the air relative to the total amount the air can hold. How much water vapor can the air hold? That depends on temperature. Warm air can hold more water vapor than cool air. You can see this in Figure 16.1. People often say, its not the heat but the humidity. Humidity can make a hot day feel even hotter. When sweat evaporates, it cools your body. But sweat cant evaporate when the air already contains as much water vapor as it can hold. The heat index is a measure of what the temperature feels like because of the humidity. You can see the heat index in Figure 16.2. Youve probably noticed dew on the grass on a summer morning. Why does dew form? Remember that the land heats up and cools down fairly readily. So when night comes, the land cools. Air that was warm and humid in the daytime also cools over night. As the air cools, it can hold less water vapor. Some of the water vapor condenses on the cool surfaces, such as blades of grass. The temperature at which water vapor condenses is called the dew point. If this temperature is below freezing, ice crystals of frost form instead of dew. As you can see in Figure 16.1, the dew point occurs at 100 percent relative humidity. Can you explain why? Clouds form when air in the atmosphere reaches the dew point. Clouds may form anywhere in the troposphere. Clouds that form on the ground are called fog. Clouds form when water vapor condenses around particles in the air. The particles are specks of matter, such as dust or smoke. Billions of these tiny water droplets come together to make up a cloud. If the air is very cold, ice crystals form instead of liquid water. Clouds are classified on the basis of where and how they form. Three main types of clouds are cirrus, stratus, and cumulus. Figure 16.3 shows these and other types of clouds. Cirrus clouds form high in the troposphere. Because it is so cold they are made of ice crystals. They are thin and wispy. Cirrus clouds dont usually produce precipitation, but they may be a sign that wet weather is coming. Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means rain. Cumulus clouds are white and puffy. Convection currents make them grow upward and they may grow very tall. When they produce rain, they are called cumulonimbus. Clouds can affect the temperature on Earths surface. During the day, thick clouds block some of the Suns rays. This keeps the surface from heating up as much as it would on a clear day. At night, thick clouds prevent
|
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The Green Revolution has brought enormous impacts to the planet. Natural landscapes have been altered to create farmland and cities. Already, half of the ice-free lands have been converted to human uses. Estimates are that by 2030, that number will be more than 70%. Forests and other landscapes have been cleared for farming or urban areas. Rivers have been dammed and the water is transported by canals for irrigation and domestic uses. Ecologically sensitive areas have been altered: wetlands are now drained and coastlines are developed. Modern agricultural practices produce a lot of pollution (Figure 1.1). Some pesticides are toxic. Dead zones grow as fertilizers drain off farmland and introduce nutrients into lakes and coastal areas. Farm machines and vehicles used to transport crops produce air pollutants. Pollutants enter the air, water, or are spilled onto the land. Moreover, many types of pollution easily move between air, water, and land. As a result, no location or organism not even polar bears in the remote Arctic is free from pollution. The increased numbers of people have other impacts on the planet. Humans do not just need food. They also need clean water, secure shelter, and a safe place for their wastes. These needs are met to different degrees in different nations and among different socioeconomic classes of people. For example, about 1.2 billion of the worlds people do not have enough clean water for drinking and washing each day (Figure 1.2). The addition of more people has not just resulted in more poor people. A large percentage of people expect much more than to have their basic needs met. For about one-quarter of people there is an abundance of food, plenty of water, and a secure home. Comfortable temperatures are made possible by heating and cooling systems, rapid trans- portation is available by motor vehicles or a well-developed public transportation system, instant communication takes place by phones and email, and many other luxuries are available that were not even dreamed of only a few The percentage of people in the world that live in abject poverty is decreasing some- what globally, but increasing in some re- gions, such as Sub-Saharan Africa. decades ago. All of these require resources in order to be produced, and fossil fuels in order to be powered (Figure Many people refer to the abundance of luxury items in these peoples lives as over-consumption. People in developed nations use 32 times more resources than people in the developing countries of the world. Click image to the left or use the URL below. URL: Click image to the left or use the URL below. URL:
|
which of these regions is experiencing an increase in abject poverty?
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In an endothermic reaction, it takes more energy to break bonds in the reactants than is released when new bonds form in the products. The word "endothermic" literally means "taking in heat." A constant input of energy, often in the form of heat, is needed in an endothermic reaction. Not enough energy is released when products form to break more bonds in the reactants. Additional energy is needed to keep the reaction going. The general equation for an endothermic reaction is: Reactants + Energy ! Products In many endothermic reactions, heat is absorbed from the surroundings. As a result, the temperature drops. The drop in temperature may be great enough to cause liquid products to freeze. Thats what happens in the endothermic reaction at this URL: One of the most important endothermic reactions is photosynthesis. In this reaction, plants synthesize glucose (C6 H12 O6 ) from carbon dioxide (CO2 ) and water (H2 O). They also release oxygen (O2 ). The energy for photo- synthesis comes from light (see Figure 8.12). Without light energy, photosynthesis cannot occur. The chemical equation for photosynthesis is: 6CO2 + 6H2 O ! C6 H12 O6 + 6O2 In an exothermic reaction, it takes less energy to break bonds in the reactants than is released when new bonds form in the products. The word "exothermic" literally means "turning out heat." Energy, often in the form of heat, is released as an exothermic reaction occurs. The general equation for an exothermic reaction is: Reactants ! Products + Energy If the energy is released as heat, an exothermic reaction results in a rise in temperature. Thats what happens in the exothermic reaction at the URL below. Combustion reactions are examples of exothermic reactions. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in Figure 8.13. You can see the light energy it is giving off. If you were standing near the fire, you would also feel its heat. Whether a reaction absorbs energy or releases energy, there is no overall change in the amount of energy. Energy cannot be created or destroyed. This is the law of conservation of energy. Energy can change form for example, from electricity to light but the same amount of energy always remains. If energy cannot be destroyed, what happens to the energy that is absorbed in an endothermic reaction? The energy is stored in the chemical bonds of the products. This form of energy is called chemical energy. In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings when the reaction occurs. The graphs in Figure 8.14 show the chemical energy of reactants and products in each type of reaction. All chemical reactions, even exothermic reactions, need a certain amount of energy to get started. This energy is called activation energy. For example, activation energy is needed to start a car. Turning the key causes a spark that activates the burning of gasoline in the engine. The combustion of gas wont occur without the spark of energy to begin the reaction. Why is activation energy needed? A reaction wont occur unless atoms or molecules of reactants come together. This happens only if the particles are moving, and movement takes energy. Often, reactants have to overcome forces that push them apart. This takes energy as well. Still more energy is needed to start breaking bonds in reactants. The graphs in Figure 8.15 show the changes in energy in endothermic and exothermic reactions. Both reactions need the same amount of activation energy in order to begin. You have probably used activation energy to start a chemical reaction. For example, if youve ever used a match to light a campfire, then you provided the activation energy needed to start a combustion reaction. Combustion is exothermic. Once a fire starts to burn, it releases enough energy to activate the next reaction, and the next, and so on. However, wood will not burst
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The energy needed for photosynthesis is in the form of
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In an endothermic reaction, it takes more energy to break bonds in the reactants than is released when new bonds form in the products. The word "endothermic" literally means "taking in heat." A constant input of energy, often in the form of heat, is needed in an endothermic reaction. Not enough energy is released when products form to break more bonds in the reactants. Additional energy is needed to keep the reaction going. The general equation for an endothermic reaction is: Reactants + Energy ! Products In many endothermic reactions, heat is absorbed from the surroundings. As a result, the temperature drops. The drop in temperature may be great enough to cause liquid products to freeze. Thats what happens in the endothermic reaction at this URL: One of the most important endothermic reactions is photosynthesis. In this reaction, plants synthesize glucose (C6 H12 O6 ) from carbon dioxide (CO2 ) and water (H2 O). They also release oxygen (O2 ). The energy for photo- synthesis comes from light (see Figure 8.12). Without light energy, photosynthesis cannot occur. The chemical equation for photosynthesis is: 6CO2 + 6H2 O ! C6 H12 O6 + 6O2 In an exothermic reaction, it takes less energy to break bonds in the reactants than is released when new bonds form in the products. The word "exothermic" literally means "turning out heat." Energy, often in the form of heat, is released as an exothermic reaction occurs. The general equation for an exothermic reaction is: Reactants ! Products + Energy If the energy is released as heat, an exothermic reaction results in a rise in temperature. Thats what happens in the exothermic reaction at the URL below. Combustion reactions are examples of exothermic reactions. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in Figure 8.13. You can see the light energy it is giving off. If you were standing near the fire, you would also feel its heat. Whether a reaction absorbs energy or releases energy, there is no overall change in the amount of energy. Energy cannot be created or destroyed. This is the law of conservation of energy. Energy can change form for example, from electricity to light but the same amount of energy always remains. If energy cannot be destroyed, what happens to the energy that is absorbed in an endothermic reaction? The energy is stored in the chemical bonds of the products. This form of energy is called chemical energy. In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings when the reaction occurs. The graphs in Figure 8.14 show the chemical energy of reactants and products in each type of reaction. All chemical reactions, even exothermic reactions, need a certain amount of energy to get started. This energy is called activation energy. For example, activation energy is needed to start a car. Turning the key causes a spark that activates the burning of gasoline in the engine. The combustion of gas wont occur without the spark of energy to begin the reaction. Why is activation energy needed? A reaction wont occur unless atoms or molecules of reactants come together. This happens only if the particles are moving, and movement takes energy. Often, reactants have to overcome forces that push them apart. This takes energy as well. Still more energy is needed to start breaking bonds in reactants. The graphs in Figure 8.15 show the changes in energy in endothermic and exothermic reactions. Both reactions need the same amount of activation energy in order to begin. You have probably used activation energy to start a chemical reaction. For example, if youve ever used a match to light a campfire, then you provided the activation energy needed to start a combustion reaction. Combustion is exothermic. Once a fire starts to burn, it releases enough energy to activate the next reaction, and the next, and so on. However, wood will not burst
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When products have less chemical energy than reactants, a chemical reaction
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In an endothermic reaction, it takes more energy to break bonds in the reactants than is released when new bonds form in the products. The word "endothermic" literally means "taking in heat." A constant input of energy, often in the form of heat, is needed in an endothermic reaction. Not enough energy is released when products form to break more bonds in the reactants. Additional energy is needed to keep the reaction going. The general equation for an endothermic reaction is: Reactants + Energy ! Products In many endothermic reactions, heat is absorbed from the surroundings. As a result, the temperature drops. The drop in temperature may be great enough to cause liquid products to freeze. Thats what happens in the endothermic reaction at this URL: One of the most important endothermic reactions is photosynthesis. In this reaction, plants synthesize glucose (C6 H12 O6 ) from carbon dioxide (CO2 ) and water (H2 O). They also release oxygen (O2 ). The energy for photo- synthesis comes from light (see Figure 8.12). Without light energy, photosynthesis cannot occur. The chemical equation for photosynthesis is: 6CO2 + 6H2 O ! C6 H12 O6 + 6O2 In an exothermic reaction, it takes less energy to break bonds in the reactants than is released when new bonds form in the products. The word "exothermic" literally means "turning out heat." Energy, often in the form of heat, is released as an exothermic reaction occurs. The general equation for an exothermic reaction is: Reactants ! Products + Energy If the energy is released as heat, an exothermic reaction results in a rise in temperature. Thats what happens in the exothermic reaction at the URL below. Combustion reactions are examples of exothermic reactions. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in Figure 8.13. You can see the light energy it is giving off. If you were standing near the fire, you would also feel its heat. Whether a reaction absorbs energy or releases energy, there is no overall change in the amount of energy. Energy cannot be created or destroyed. This is the law of conservation of energy. Energy can change form for example, from electricity to light but the same amount of energy always remains. If energy cannot be destroyed, what happens to the energy that is absorbed in an endothermic reaction? The energy is stored in the chemical bonds of the products. This form of energy is called chemical energy. In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings when the reaction occurs. The graphs in Figure 8.14 show the chemical energy of reactants and products in each type of reaction. All chemical reactions, even exothermic reactions, need a certain amount of energy to get started. This energy is called activation energy. For example, activation energy is needed to start a car. Turning the key causes a spark that activates the burning of gasoline in the engine. The combustion of gas wont occur without the spark of energy to begin the reaction. Why is activation energy needed? A reaction wont occur unless atoms or molecules of reactants come together. This happens only if the particles are moving, and movement takes energy. Often, reactants have to overcome forces that push them apart. This takes energy as well. Still more energy is needed to start breaking bonds in reactants. The graphs in Figure 8.15 show the changes in energy in endothermic and exothermic reactions. Both reactions need the same amount of activation energy in order to begin. You have probably used activation energy to start a chemical reaction. For example, if youve ever used a match to light a campfire, then you provided the activation energy needed to start a combustion reaction. Combustion is exothermic. Once a fire starts to burn, it releases enough energy to activate the next reaction, and the next, and so on. However, wood will not burst
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In an endothermic reaction, it takes more energy to break bonds in the reactants than is released when new bonds form in the products. The word "endothermic" literally means "taking in heat." A constant input of energy, often in the form of heat, is needed in an endothermic reaction. Not enough energy is released when products form to break more bonds in the reactants. Additional energy is needed to keep the reaction going. The general equation for an endothermic reaction is: Reactants + Energy ! Products In many endothermic reactions, heat is absorbed from the surroundings. As a result, the temperature drops. The drop in temperature may be great enough to cause liquid products to freeze. Thats what happens in the endothermic reaction at this URL: One of the most important endothermic reactions is photosynthesis. In this reaction, plants synthesize glucose (C6 H12 O6 ) from carbon dioxide (CO2 ) and water (H2 O). They also release oxygen (O2 ). The energy for photo- synthesis comes from light (see Figure 8.12). Without light energy, photosynthesis cannot occur. The chemical equation for photosynthesis is: 6CO2 + 6H2 O ! C6 H12 O6 + 6O2 In an exothermic reaction, it takes less energy to break bonds in the reactants than is released when new bonds form in the products. The word "exothermic" literally means "turning out heat." Energy, often in the form of heat, is released as an exothermic reaction occurs. The general equation for an exothermic reaction is: Reactants ! Products + Energy If the energy is released as heat, an exothermic reaction results in a rise in temperature. Thats what happens in the exothermic reaction at the URL below. Combustion reactions are examples of exothermic reactions. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in Figure 8.13. You can see the light energy it is giving off. If you were standing near the fire, you would also feel its heat. Whether a reaction absorbs energy or releases energy, there is no overall change in the amount of energy. Energy cannot be created or destroyed. This is the law of conservation of energy. Energy can change form for example, from electricity to light but the same amount of energy always remains. If energy cannot be destroyed, what happens to the energy that is absorbed in an endothermic reaction? The energy is stored in the chemical bonds of the products. This form of energy is called chemical energy. In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings when the reaction occurs. The graphs in Figure 8.14 show the chemical energy of reactants and products in each type of reaction. All chemical reactions, even exothermic reactions, need a certain amount of energy to get started. This energy is called activation energy. For example, activation energy is needed to start a car. Turning the key causes a spark that activates the burning of gasoline in the engine. The combustion of gas wont occur without the spark of energy to begin the reaction. Why is activation energy needed? A reaction wont occur unless atoms or molecules of reactants come together. This happens only if the particles are moving, and movement takes energy. Often, reactants have to overcome forces that push them apart. This takes energy as well. Still more energy is needed to start breaking bonds in reactants. The graphs in Figure 8.15 show the changes in energy in endothermic and exothermic reactions. Both reactions need the same amount of activation energy in order to begin. You have probably used activation energy to start a chemical reaction. For example, if youve ever used a match to light a campfire, then you provided the activation energy needed to start a combustion reaction. Combustion is exothermic. Once a fire starts to burn, it releases enough energy to activate the next reaction, and the next, and so on. However, wood will not burst
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In an endothermic reaction, it takes more energy to break bonds in the reactants than is released when new bonds form in the products. The word "endothermic" literally means "taking in heat." A constant input of energy, often in the form of heat, is needed in an endothermic reaction. Not enough energy is released when products form to break more bonds in the reactants. Additional energy is needed to keep the reaction going. The general equation for an endothermic reaction is: Reactants + Energy ! Products In many endothermic reactions, heat is absorbed from the surroundings. As a result, the temperature drops. The drop in temperature may be great enough to cause liquid products to freeze. Thats what happens in the endothermic reaction at this URL: One of the most important endothermic reactions is photosynthesis. In this reaction, plants synthesize glucose (C6 H12 O6 ) from carbon dioxide (CO2 ) and water (H2 O). They also release oxygen (O2 ). The energy for photo- synthesis comes from light (see Figure 8.12). Without light energy, photosynthesis cannot occur. The chemical equation for photosynthesis is: 6CO2 + 6H2 O ! C6 H12 O6 + 6O2 In an exothermic reaction, it takes less energy to break bonds in the reactants than is released when new bonds form in the products. The word "exothermic" literally means "turning out heat." Energy, often in the form of heat, is released as an exothermic reaction occurs. The general equation for an exothermic reaction is: Reactants ! Products + Energy If the energy is released as heat, an exothermic reaction results in a rise in temperature. Thats what happens in the exothermic reaction at the URL below. Combustion reactions are examples of exothermic reactions. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in Figure 8.13. You can see the light energy it is giving off. If you were standing near the fire, you would also feel its heat. Whether a reaction absorbs energy or releases energy, there is no overall change in the amount of energy. Energy cannot be created or destroyed. This is the law of conservation of energy. Energy can change form for example, from electricity to light but the same amount of energy always remains. If energy cannot be destroyed, what happens to the energy that is absorbed in an endothermic reaction? The energy is stored in the chemical bonds of the products. This form of energy is called chemical energy. In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings when the reaction occurs. The graphs in Figure 8.14 show the chemical energy of reactants and products in each type of reaction. All chemical reactions, even exothermic reactions, need a certain amount of energy to get started. This energy is called activation energy. For example, activation energy is needed to start a car. Turning the key causes a spark that activates the burning of gasoline in the engine. The combustion of gas wont occur without the spark of energy to begin the reaction. Why is activation energy needed? A reaction wont occur unless atoms or molecules of reactants come together. This happens only if the particles are moving, and movement takes energy. Often, reactants have to overcome forces that push them apart. This takes energy as well. Still more energy is needed to start breaking bonds in reactants. The graphs in Figure 8.15 show the changes in energy in endothermic and exothermic reactions. Both reactions need the same amount of activation energy in order to begin. You have probably used activation energy to start a chemical reaction. For example, if youve ever used a match to light a campfire, then you provided the activation energy needed to start a combustion reaction. Combustion is exothermic. Once a fire starts to burn, it releases enough energy to activate the next reaction, and the next, and so on. However, wood will not burst
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In an endothermic reaction, it takes more energy to break bonds in the reactants than is released when new bonds form in the products. The word "endothermic" literally means "taking in heat." A constant input of energy, often in the form of heat, is needed in an endothermic reaction. Not enough energy is released when products form to break more bonds in the reactants. Additional energy is needed to keep the reaction going. The general equation for an endothermic reaction is: Reactants + Energy ! Products In many endothermic reactions, heat is absorbed from the surroundings. As a result, the temperature drops. The drop in temperature may be great enough to cause liquid products to freeze. Thats what happens in the endothermic reaction at this URL: One of the most important endothermic reactions is photosynthesis. In this reaction, plants synthesize glucose (C6 H12 O6 ) from carbon dioxide (CO2 ) and water (H2 O). They also release oxygen (O2 ). The energy for photo- synthesis comes from light (see Figure 8.12). Without light energy, photosynthesis cannot occur. The chemical equation for photosynthesis is: 6CO2 + 6H2 O ! C6 H12 O6 + 6O2 In an exothermic reaction, it takes less energy to break bonds in the reactants than is released when new bonds form in the products. The word "exothermic" literally means "turning out heat." Energy, often in the form of heat, is released as an exothermic reaction occurs. The general equation for an exothermic reaction is: Reactants ! Products + Energy If the energy is released as heat, an exothermic reaction results in a rise in temperature. Thats what happens in the exothermic reaction at the URL below. Combustion reactions are examples of exothermic reactions. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in Figure 8.13. You can see the light energy it is giving off. If you were standing near the fire, you would also feel its heat. Whether a reaction absorbs energy or releases energy, there is no overall change in the amount of energy. Energy cannot be created or destroyed. This is the law of conservation of energy. Energy can change form for example, from electricity to light but the same amount of energy always remains. If energy cannot be destroyed, what happens to the energy that is absorbed in an endothermic reaction? The energy is stored in the chemical bonds of the products. This form of energy is called chemical energy. In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings when the reaction occurs. The graphs in Figure 8.14 show the chemical energy of reactants and products in each type of reaction. All chemical reactions, even exothermic reactions, need a certain amount of energy to get started. This energy is called activation energy. For example, activation energy is needed to start a car. Turning the key causes a spark that activates the burning of gasoline in the engine. The combustion of gas wont occur without the spark of energy to begin the reaction. Why is activation energy needed? A reaction wont occur unless atoms or molecules of reactants come together. This happens only if the particles are moving, and movement takes energy. Often, reactants have to overcome forces that push them apart. This takes energy as well. Still more energy is needed to start breaking bonds in reactants. The graphs in Figure 8.15 show the changes in energy in endothermic and exothermic reactions. Both reactions need the same amount of activation energy in order to begin. You have probably used activation energy to start a chemical reaction. For example, if youve ever used a match to light a campfire, then you provided the activation energy needed to start a combustion reaction. Combustion is exothermic. Once a fire starts to burn, it releases enough energy to activate the next reaction, and the next, and so on. However, wood will not burst
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In an endothermic reaction, it takes more energy to break bonds in the reactants than is released when new bonds form in the products. The word "endothermic" literally means "taking in heat." A constant input of energy, often in the form of heat, is needed in an endothermic reaction. Not enough energy is released when products form to break more bonds in the reactants. Additional energy is needed to keep the reaction going. The general equation for an endothermic reaction is: Reactants + Energy ! Products In many endothermic reactions, heat is absorbed from the surroundings. As a result, the temperature drops. The drop in temperature may be great enough to cause liquid products to freeze. Thats what happens in the endothermic reaction at this URL: One of the most important endothermic reactions is photosynthesis. In this reaction, plants synthesize glucose (C6 H12 O6 ) from carbon dioxide (CO2 ) and water (H2 O). They also release oxygen (O2 ). The energy for photo- synthesis comes from light (see Figure 8.12). Without light energy, photosynthesis cannot occur. The chemical equation for photosynthesis is: 6CO2 + 6H2 O ! C6 H12 O6 + 6O2 In an exothermic reaction, it takes less energy to break bonds in the reactants than is released when new bonds form in the products. The word "exothermic" literally means "turning out heat." Energy, often in the form of heat, is released as an exothermic reaction occurs. The general equation for an exothermic reaction is: Reactants ! Products + Energy If the energy is released as heat, an exothermic reaction results in a rise in temperature. Thats what happens in the exothermic reaction at the URL below. Combustion reactions are examples of exothermic reactions. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in Figure 8.13. You can see the light energy it is giving off. If you were standing near the fire, you would also feel its heat. Whether a reaction absorbs energy or releases energy, there is no overall change in the amount of energy. Energy cannot be created or destroyed. This is the law of conservation of energy. Energy can change form for example, from electricity to light but the same amount of energy always remains. If energy cannot be destroyed, what happens to the energy that is absorbed in an endothermic reaction? The energy is stored in the chemical bonds of the products. This form of energy is called chemical energy. In an endothermic reaction, the products have more stored chemical energy than the reactants. In an exothermic reaction, the opposite is true. The products have less stored chemical energy than the reactants. The excess energy in the reactants is released to the surroundings when the reaction occurs. The graphs in Figure 8.14 show the chemical energy of reactants and products in each type of reaction. All chemical reactions, even exothermic reactions, need a certain amount of energy to get started. This energy is called activation energy. For example, activation energy is needed to start a car. Turning the key causes a spark that activates the burning of gasoline in the engine. The combustion of gas wont occur without the spark of energy to begin the reaction. Why is activation energy needed? A reaction wont occur unless atoms or molecules of reactants come together. This happens only if the particles are moving, and movement takes energy. Often, reactants have to overcome forces that push them apart. This takes energy as well. Still more energy is needed to start breaking bonds in reactants. The graphs in Figure 8.15 show the changes in energy in endothermic and exothermic reactions. Both reactions need the same amount of activation energy in order to begin. You have probably used activation energy to start a chemical reaction. For example, if youve ever used a match to light a campfire, then you provided the activation energy needed to start a combustion reaction. Combustion is exothermic. Once a fire starts to burn, it releases enough energy to activate the next reaction, and the next, and so on. However, wood will not burst
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Some minerals are very useful. An ore is a rock that contains minerals with useful elements. Aluminum in bauxite ore (Figure 1.1) is extracted from the ground and refined to be used in aluminum foil and many other products. The cost of creating a product from a mineral depends on how abundant the mineral is and how much the extraction and refining processes cost. Environmental damage from these processes is often not figured into a products cost. It is important to use mineral resources wisely. Geologic processes create and concentrate minerals that are valuable natural resources. Geologists study geological formations and then test the physical and chemical properties of soil and rocks to locate possible ores and determine their size and concentration. A mineral deposit will only be mined if it is profitable. A concentration of minerals is only called an ore deposit if it is profitable to mine. There are many ways to mine ores. Aluminum is made from the aluminum- bearing minerals in bauxite. Surface mining allows extraction of ores that are close to Earths surface. Overlying rock is blasted and the rock that contains the valuable minerals is placed in a truck and taken to a refinery. As pictured in Figure 1.2, surface mining includes open-pit mining and mountaintop removal. Other methods of surface mining include strip mining, placer mining, and dredging. Strip mining is like open pit mining but with material removed along a strip. These different forms of surface mining are methods of extracting ores close to Earths surface. Placers are valuable minerals found in stream gravels. Californias nickname, the Golden State, can be traced back to the discovery of placer deposits of gold in 1848. The gold weathered out of hard metamorphic rock in the western Sierra Nevada, which also contains deposits of copper, lead, zinc, silver, chromite, and other valuable minerals. The Underground mining is used to recover ores that are deeper into Earths surface. Miners blast and tunnel into rock to gain access to the ores. How underground mining is approached from above, below, or sideways depends on the placement of the ore body, its depth, the concentration of ore, and the strength of the surrounding rock. Underground mining is very expensive and dangerous. Fresh air and lights must also be brought into the tunnels for the miners, and accidents are far too common. The ores journey to becoming a useable material is only just beginning when the ore leaves the mine (Figure separated out of the ore. A few methods for extracting ore are: heap leaching: the addition of chemicals, such as cyanide or acid, to remove ore. flotation: the addition of a compound that attaches to the valuable mineral and floats. smelting: roasting rock, causing it to segregate into layers so the mineral can be extracted. To extract the metal from the ore, the rock is melted at a temperature greater than 900o C, which requires a lot of energy. Extracting metal from rock is so energy-intensive that if you recycle just 40 aluminum cans, you will save the energy equivalent of one gallon of gasoline.
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Some minerals are very useful. An ore is a rock that contains minerals with useful elements. Aluminum in bauxite ore (Figure 1.1) is extracted from the ground and refined to be used in aluminum foil and many other products. The cost of creating a product from a mineral depends on how abundant the mineral is and how much the extraction and refining processes cost. Environmental damage from these processes is often not figured into a products cost. It is important to use mineral resources wisely. Geologic processes create and concentrate minerals that are valuable natural resources. Geologists study geological formations and then test the physical and chemical properties of soil and rocks to locate possible ores and determine their size and concentration. A mineral deposit will only be mined if it is profitable. A concentration of minerals is only called an ore deposit if it is profitable to mine. There are many ways to mine ores. Aluminum is made from the aluminum- bearing minerals in bauxite. Surface mining allows extraction of ores that are close to Earths surface. Overlying rock is blasted and the rock that contains the valuable minerals is placed in a truck and taken to a refinery. As pictured in Figure 1.2, surface mining includes open-pit mining and mountaintop removal. Other methods of surface mining include strip mining, placer mining, and dredging. Strip mining is like open pit mining but with material removed along a strip. These different forms of surface mining are methods of extracting ores close to Earths surface. Placers are valuable minerals found in stream gravels. Californias nickname, the Golden State, can be traced back to the discovery of placer deposits of gold in 1848. The gold weathered out of hard metamorphic rock in the western Sierra Nevada, which also contains deposits of copper, lead, zinc, silver, chromite, and other valuable minerals. The Underground mining is used to recover ores that are deeper into Earths surface. Miners blast and tunnel into rock to gain access to the ores. How underground mining is approached from above, below, or sideways depends on the placement of the ore body, its depth, the concentration of ore, and the strength of the surrounding rock. Underground mining is very expensive and dangerous. Fresh air and lights must also be brought into the tunnels for the miners, and accidents are far too common. The ores journey to becoming a useable material is only just beginning when the ore leaves the mine (Figure separated out of the ore. A few methods for extracting ore are: heap leaching: the addition of chemicals, such as cyanide or acid, to remove ore. flotation: the addition of a compound that attaches to the valuable mineral and floats. smelting: roasting rock, causing it to segregate into layers so the mineral can be extracted. To extract the metal from the ore, the rock is melted at a temperature greater than 900o C, which requires a lot of energy. Extracting metal from rock is so energy-intensive that if you recycle just 40 aluminum cans, you will save the energy equivalent of one gallon of gasoline.
|
when valuable minerals are taken from stream gravels, this is called
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Some minerals are very useful. An ore is a rock that contains minerals with useful elements. Aluminum in bauxite ore (Figure 1.1) is extracted from the ground and refined to be used in aluminum foil and many other products. The cost of creating a product from a mineral depends on how abundant the mineral is and how much the extraction and refining processes cost. Environmental damage from these processes is often not figured into a products cost. It is important to use mineral resources wisely. Geologic processes create and concentrate minerals that are valuable natural resources. Geologists study geological formations and then test the physical and chemical properties of soil and rocks to locate possible ores and determine their size and concentration. A mineral deposit will only be mined if it is profitable. A concentration of minerals is only called an ore deposit if it is profitable to mine. There are many ways to mine ores. Aluminum is made from the aluminum- bearing minerals in bauxite. Surface mining allows extraction of ores that are close to Earths surface. Overlying rock is blasted and the rock that contains the valuable minerals is placed in a truck and taken to a refinery. As pictured in Figure 1.2, surface mining includes open-pit mining and mountaintop removal. Other methods of surface mining include strip mining, placer mining, and dredging. Strip mining is like open pit mining but with material removed along a strip. These different forms of surface mining are methods of extracting ores close to Earths surface. Placers are valuable minerals found in stream gravels. Californias nickname, the Golden State, can be traced back to the discovery of placer deposits of gold in 1848. The gold weathered out of hard metamorphic rock in the western Sierra Nevada, which also contains deposits of copper, lead, zinc, silver, chromite, and other valuable minerals. The Underground mining is used to recover ores that are deeper into Earths surface. Miners blast and tunnel into rock to gain access to the ores. How underground mining is approached from above, below, or sideways depends on the placement of the ore body, its depth, the concentration of ore, and the strength of the surrounding rock. Underground mining is very expensive and dangerous. Fresh air and lights must also be brought into the tunnels for the miners, and accidents are far too common. The ores journey to becoming a useable material is only just beginning when the ore leaves the mine (Figure separated out of the ore. A few methods for extracting ore are: heap leaching: the addition of chemicals, such as cyanide or acid, to remove ore. flotation: the addition of a compound that attaches to the valuable mineral and floats. smelting: roasting rock, causing it to segregate into layers so the mineral can be extracted. To extract the metal from the ore, the rock is melted at a temperature greater than 900o C, which requires a lot of energy. Extracting metal from rock is so energy-intensive that if you recycle just 40 aluminum cans, you will save the energy equivalent of one gallon of gasoline.
|
when miners blast and tunnel into rock to gain access to ores, this is called ____________.
|
[
"underground mining"
] |
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A wedge is simple machine that consists of two inclined planes, giving it a thin end and thick end, as you can see in the Figure 1.1. A wedge is used to cut or split apart objects. Force is applied to the thick end of the wedge, and the wedge, in turn, applies force to the object along both of its sloping sides. This force causes the object to split apart. A knife is another example of a wedge. In the Figure 1.2, a knife is being used to chop tough pecans. The job is easy to do with the knife because of the wedge shape of the blade. The very thin edge of the blade easily enters and cuts through the pecans. The mechanical advantage of a simple machine is the factor by which it multiplies the force applied to the machine. It is the ratio of the output force to the input force. A wedge applies more force to the object (output force) than the user applies to the wedge (input force), so the mechanical advantage of a wedge is greater than 1. A longer, thinner wedge has a greater mechanical advantage than a shorter, wider wedge. With all wedges, the trade-off is that the output force is applied over a shorter distance, so force may need to be applied to the wedge repeatedly to push it through the object. Q: Which wedge in the Figure 1.3 do you think would do the same amount of work with less input force? A: The wedge on the left has a greater mechanical advantage, so it would do the same amount of work with less input force.
|
a wedge
|
[
"consists of two inclined planes."
] |
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Every major advance in agriculture has allowed global population to increase. Early farmers could settle down to a steady food supply. Irrigation, the ability to clear large swaths of land for farming efficiently, and the development of farm machines powered by fossil fuels allowed people to grow more food and transport it to where it was needed. What is Earths carrying capacity for humans? Are humans now exceeding Earths carrying capacity for our species? Many anthropologists say that the carrying capacity of humans on the planet without agriculture is about 10 million (Figure 1.1). This population was reached about 10,000 years ago. At the time, people lived together in small bands of hunters and gatherers. Typically men hunted and fished; women gathered nuts and vegetables. Obviously, human populations have blown past this hypothetical carrying capacity. By using our brains, our erect posture, and our hands, we have been able to manipulate our environment in ways that no other species has ever done. What have been the important developments that have allowed population to grow? About 10,000 years ago, we developed the ability to grow our own food. Farming increased the yield of food plants and allowed people to have food available year round. Animals were domesticated to provide meat. With agriculture, people could settle down, so that they no longer needed to carry all their possessions (Figure 1.2). They could develop better farming practices and store food for when it was difficult to grow. Agriculture allowed people to settle in towns and cities. More advanced farming practices allowed a single farmer to grow food for many more people. When advanced farming practices allowed farmers to grow more food than they needed for their families (Figure The next major stage in the growth of the human population was the Industrial Revolution, which started in the late 1700s (Figure 1.4). This major historical event marks when products were first mass-produced and when fossil fuels were first widely used for power. The Green Revolution has allowed the addition of billions of people to the population in the past few decades. The Green Revolution has improved agricultural productivity by: Improving crops by selecting for traits that promote productivity; recently, genetically engineered crops have been introduced. Increasing the use of artificial fertilizers and chemical pesticides. About 23 times more fertilizer and 50 times more pesticides are used around the world than were used just 50 years ago (Figure 1.5). Agricultural machinery: plowing, tilling, fertilizing, picking, and transporting are all done by machines. About 17% of the energy used each year in the United States is for agriculture. Increasing access to water. Many farming regions depend on groundwater, which is not a renewable resource. Some regions will eventually run out of this water source. Currently about 70% of the worlds fresh water is used for agriculture. Rows of a single crop and heavy ma- chinery are normal sights for modern day farms. The Green Revolution has increased the productivity of farms immensely. A century ago, a single farmer produced enough food for 2.5 people, but now a farmer can feed more than 130 people. The Green Revolution is credited for feeding 1 billion people that would not otherwise have been able to live. The flip side to this is that for the population to continue to grow, more advances in agriculture and an ever increasing supply of water will be needed. Weve increased the carrying capacity for humans by our genius: growing crops, trading for needed materials, and designing ways to exploit resources that are difficult to get at, such as groundwater. And most of these resources are limited. The question is, even though we have increased the carrying capacity of the planet, have we now exceeded it (Figure There is not yet an answer to that question, but there are many different opinions. In the eighteenth century, Thomas Malthus predicted that human population would continue to grow until we had exhausted our resources. At that point, humans would become victims of famine, disease, or war. This has not happened, at least not yet. Some scientists think that the carrying capacity of the planet is about 1 billion people, not the 7 billion people we have today
|
this scientist in the eighteenth century predicted that human population would continue to grow until we had exhausted our resources.
|
[
"thomas malthus"
] |
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Vitamins and minerals are also nutrients. They do not provide energy, but they are needed for good health. Vitamins are organic compounds that the body needs in small amounts to function properly. Humans need 13 different vitamins. Some of them are listed below ( Table 1.1). The table also shows how much of each vitamin you need every day. Vitamins have many roles in the body. For example, Vitamin A helps maintain good vision. Vitamin B9 helps form red blood cells. Vitamin K is needed for blood to clot when you have a cut or other wound. Vitamin Necessary for Available from Daily Amount Required (at ages 913 years) Vitamin Necessary for Available from A Good vision B1 Healthy nerves B3 Healthy skin and nerves B9 Red blood cells B12 Healthy nerves C Growth and repair of tis- sues Healthy bones and teeth Blood to clot Carrots, spinach, milk, eggs Whole wheat, peas, meat, beans, fish, peanuts Beets, liver, pork, turkey, fish, peanuts Liver, peas, dried beans, leafy green vegetables Meat, liver, milk, shell- fish, eggs Oranges, grapefruits, red peppers, broccoli Milk, salmon, tuna, eggs Spinach, brussels sprouts, milk, eggs D K Daily Amount Required (at ages 913 years) 600 g (1 g = 1 106 g) 0.9 mg (1 mg = 1 103 g) 12 mg 300 g 1.8 g 45 mg 5 g 60 g Some vitamins are produced in the body. For example, vitamin D is made in the skin when it is exposed to sunlight. Vitamins B12 and K are produced by bacteria that normally live inside the body. Most other vitamins must come from foods. Foods that are good sources of vitamins include whole grains, vegetables, fruits, and milk ( Table 1.1). Not getting enough vitamins can cause health problems. For example, too little vitamin C causes a disease called scurvy. People with scurvy have bleeding gums, nosebleeds, and other symptoms. Minerals are chemical elements that are needed for body processes. Minerals that you need in relatively large amounts are listed below ( Table 1.2). Minerals that you need in smaller amounts include iodine, iron, and zinc. Minerals have many important roles in the body. For example, calcium and phosphorus are needed for strong bones and teeth. Potassium and sodium are needed for muscles and nerves to work normally. Mineral Necessary for Available from Calcium Strong bones and teeth Chloride Magnesium Proper balance of water and salts in body Strong bones Phosphorus Strong bones and teeth Potassium Muscles and nerves to work normally Muscles and nerves to work normally Milk, soy milk, leafy green vegetables Table salt, most packaged foods Whole grains, leafy green vegetables, nuts Meat, poultry, whole grains Meats, grains, bananas, orange juice Table salt, most packaged foods Sodium Daily Amount Required (at ages 913 years) 1,300 mg 2.3 g 240 mg 1,250 mg 4.5 g 1.5 g Your body cannot produce any of the minerals that it needs. Instead, you must get minerals from the foods you eat. Good sources of minerals include milk, leafy green vegetables, and whole grains ( Table 1.2). Not getting enough minerals can cause health problems. For example, too little calcium may cause osteoporosis. This is a disease in which bones become soft and break easily. Getting too much of some minerals can also cause health problems. Many people get too much sodium. Sodium is added to most packaged foods. People often add more sodium to their food by using table salt. Too much sodium causes high blood pressure in some people.
|
what minerals are needed for muscles and nerves to work normally?
|
[
"potassium and sodium"
] |
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Vitamins and minerals are also nutrients. They do not provide energy, but they are needed for good health. Vitamins are organic compounds that the body needs in small amounts to function properly. Humans need 13 different vitamins. Some of them are listed below ( Table 1.1). The table also shows how much of each vitamin you need every day. Vitamins have many roles in the body. For example, Vitamin A helps maintain good vision. Vitamin B9 helps form red blood cells. Vitamin K is needed for blood to clot when you have a cut or other wound. Vitamin Necessary for Available from Daily Amount Required (at ages 913 years) Vitamin Necessary for Available from A Good vision B1 Healthy nerves B3 Healthy skin and nerves B9 Red blood cells B12 Healthy nerves C Growth and repair of tis- sues Healthy bones and teeth Blood to clot Carrots, spinach, milk, eggs Whole wheat, peas, meat, beans, fish, peanuts Beets, liver, pork, turkey, fish, peanuts Liver, peas, dried beans, leafy green vegetables Meat, liver, milk, shell- fish, eggs Oranges, grapefruits, red peppers, broccoli Milk, salmon, tuna, eggs Spinach, brussels sprouts, milk, eggs D K Daily Amount Required (at ages 913 years) 600 g (1 g = 1 106 g) 0.9 mg (1 mg = 1 103 g) 12 mg 300 g 1.8 g 45 mg 5 g 60 g Some vitamins are produced in the body. For example, vitamin D is made in the skin when it is exposed to sunlight. Vitamins B12 and K are produced by bacteria that normally live inside the body. Most other vitamins must come from foods. Foods that are good sources of vitamins include whole grains, vegetables, fruits, and milk ( Table 1.1). Not getting enough vitamins can cause health problems. For example, too little vitamin C causes a disease called scurvy. People with scurvy have bleeding gums, nosebleeds, and other symptoms. Minerals are chemical elements that are needed for body processes. Minerals that you need in relatively large amounts are listed below ( Table 1.2). Minerals that you need in smaller amounts include iodine, iron, and zinc. Minerals have many important roles in the body. For example, calcium and phosphorus are needed for strong bones and teeth. Potassium and sodium are needed for muscles and nerves to work normally. Mineral Necessary for Available from Calcium Strong bones and teeth Chloride Magnesium Proper balance of water and salts in body Strong bones Phosphorus Strong bones and teeth Potassium Muscles and nerves to work normally Muscles and nerves to work normally Milk, soy milk, leafy green vegetables Table salt, most packaged foods Whole grains, leafy green vegetables, nuts Meat, poultry, whole grains Meats, grains, bananas, orange juice Table salt, most packaged foods Sodium Daily Amount Required (at ages 913 years) 1,300 mg 2.3 g 240 mg 1,250 mg 4.5 g 1.5 g Your body cannot produce any of the minerals that it needs. Instead, you must get minerals from the foods you eat. Good sources of minerals include milk, leafy green vegetables, and whole grains ( Table 1.2). Not getting enough minerals can cause health problems. For example, too little calcium may cause osteoporosis. This is a disease in which bones become soft and break easily. Getting too much of some minerals can also cause health problems. Many people get too much sodium. Sodium is added to most packaged foods. People often add more sodium to their food by using table salt. Too much sodium causes high blood pressure in some people.
|
what vitamin is important in blood clotting?
|
[
"vitamin k"
] |
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Vitamins and minerals are also nutrients. They do not provide energy, but they are needed for good health. Vitamins are organic compounds that the body needs in small amounts to function properly. Humans need 13 different vitamins. Some of them are listed below ( Table 1.1). The table also shows how much of each vitamin you need every day. Vitamins have many roles in the body. For example, Vitamin A helps maintain good vision. Vitamin B9 helps form red blood cells. Vitamin K is needed for blood to clot when you have a cut or other wound. Vitamin Necessary for Available from Daily Amount Required (at ages 913 years) Vitamin Necessary for Available from A Good vision B1 Healthy nerves B3 Healthy skin and nerves B9 Red blood cells B12 Healthy nerves C Growth and repair of tis- sues Healthy bones and teeth Blood to clot Carrots, spinach, milk, eggs Whole wheat, peas, meat, beans, fish, peanuts Beets, liver, pork, turkey, fish, peanuts Liver, peas, dried beans, leafy green vegetables Meat, liver, milk, shell- fish, eggs Oranges, grapefruits, red peppers, broccoli Milk, salmon, tuna, eggs Spinach, brussels sprouts, milk, eggs D K Daily Amount Required (at ages 913 years) 600 g (1 g = 1 106 g) 0.9 mg (1 mg = 1 103 g) 12 mg 300 g 1.8 g 45 mg 5 g 60 g Some vitamins are produced in the body. For example, vitamin D is made in the skin when it is exposed to sunlight. Vitamins B12 and K are produced by bacteria that normally live inside the body. Most other vitamins must come from foods. Foods that are good sources of vitamins include whole grains, vegetables, fruits, and milk ( Table 1.1). Not getting enough vitamins can cause health problems. For example, too little vitamin C causes a disease called scurvy. People with scurvy have bleeding gums, nosebleeds, and other symptoms. Minerals are chemical elements that are needed for body processes. Minerals that you need in relatively large amounts are listed below ( Table 1.2). Minerals that you need in smaller amounts include iodine, iron, and zinc. Minerals have many important roles in the body. For example, calcium and phosphorus are needed for strong bones and teeth. Potassium and sodium are needed for muscles and nerves to work normally. Mineral Necessary for Available from Calcium Strong bones and teeth Chloride Magnesium Proper balance of water and salts in body Strong bones Phosphorus Strong bones and teeth Potassium Muscles and nerves to work normally Muscles and nerves to work normally Milk, soy milk, leafy green vegetables Table salt, most packaged foods Whole grains, leafy green vegetables, nuts Meat, poultry, whole grains Meats, grains, bananas, orange juice Table salt, most packaged foods Sodium Daily Amount Required (at ages 913 years) 1,300 mg 2.3 g 240 mg 1,250 mg 4.5 g 1.5 g Your body cannot produce any of the minerals that it needs. Instead, you must get minerals from the foods you eat. Good sources of minerals include milk, leafy green vegetables, and whole grains ( Table 1.2). Not getting enough minerals can cause health problems. For example, too little calcium may cause osteoporosis. This is a disease in which bones become soft and break easily. Getting too much of some minerals can also cause health problems. Many people get too much sodium. Sodium is added to most packaged foods. People often add more sodium to their food by using table salt. Too much sodium causes high blood pressure in some people.
|
low levels of what mineral may cause osteoporosis?
|
[
"calcium"
] |
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Vitamins and minerals are also nutrients. They do not provide energy, but they are needed for good health. Vitamins are organic compounds that the body needs in small amounts to function properly. Humans need 13 different vitamins. Some of them are listed below ( Table 1.1). The table also shows how much of each vitamin you need every day. Vitamins have many roles in the body. For example, Vitamin A helps maintain good vision. Vitamin B9 helps form red blood cells. Vitamin K is needed for blood to clot when you have a cut or other wound. Vitamin Necessary for Available from Daily Amount Required (at ages 913 years) Vitamin Necessary for Available from A Good vision B1 Healthy nerves B3 Healthy skin and nerves B9 Red blood cells B12 Healthy nerves C Growth and repair of tis- sues Healthy bones and teeth Blood to clot Carrots, spinach, milk, eggs Whole wheat, peas, meat, beans, fish, peanuts Beets, liver, pork, turkey, fish, peanuts Liver, peas, dried beans, leafy green vegetables Meat, liver, milk, shell- fish, eggs Oranges, grapefruits, red peppers, broccoli Milk, salmon, tuna, eggs Spinach, brussels sprouts, milk, eggs D K Daily Amount Required (at ages 913 years) 600 g (1 g = 1 106 g) 0.9 mg (1 mg = 1 103 g) 12 mg 300 g 1.8 g 45 mg 5 g 60 g Some vitamins are produced in the body. For example, vitamin D is made in the skin when it is exposed to sunlight. Vitamins B12 and K are produced by bacteria that normally live inside the body. Most other vitamins must come from foods. Foods that are good sources of vitamins include whole grains, vegetables, fruits, and milk ( Table 1.1). Not getting enough vitamins can cause health problems. For example, too little vitamin C causes a disease called scurvy. People with scurvy have bleeding gums, nosebleeds, and other symptoms. Minerals are chemical elements that are needed for body processes. Minerals that you need in relatively large amounts are listed below ( Table 1.2). Minerals that you need in smaller amounts include iodine, iron, and zinc. Minerals have many important roles in the body. For example, calcium and phosphorus are needed for strong bones and teeth. Potassium and sodium are needed for muscles and nerves to work normally. Mineral Necessary for Available from Calcium Strong bones and teeth Chloride Magnesium Proper balance of water and salts in body Strong bones Phosphorus Strong bones and teeth Potassium Muscles and nerves to work normally Muscles and nerves to work normally Milk, soy milk, leafy green vegetables Table salt, most packaged foods Whole grains, leafy green vegetables, nuts Meat, poultry, whole grains Meats, grains, bananas, orange juice Table salt, most packaged foods Sodium Daily Amount Required (at ages 913 years) 1,300 mg 2.3 g 240 mg 1,250 mg 4.5 g 1.5 g Your body cannot produce any of the minerals that it needs. Instead, you must get minerals from the foods you eat. Good sources of minerals include milk, leafy green vegetables, and whole grains ( Table 1.2). Not getting enough minerals can cause health problems. For example, too little calcium may cause osteoporosis. This is a disease in which bones become soft and break easily. Getting too much of some minerals can also cause health problems. Many people get too much sodium. Sodium is added to most packaged foods. People often add more sodium to their food by using table salt. Too much sodium causes high blood pressure in some people.
|
what vitamin can be found in foods like oranges, grapefruits, and broccoli?
|
[
"vitamin c"
] |
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Vitamins and minerals are also nutrients. They do not provide energy, but they are needed for good health. Vitamins are organic compounds that the body needs in small amounts to function properly. Humans need 13 different vitamins. Some of them are listed below ( Table 1.1). The table also shows how much of each vitamin you need every day. Vitamins have many roles in the body. For example, Vitamin A helps maintain good vision. Vitamin B9 helps form red blood cells. Vitamin K is needed for blood to clot when you have a cut or other wound. Vitamin Necessary for Available from Daily Amount Required (at ages 913 years) Vitamin Necessary for Available from A Good vision B1 Healthy nerves B3 Healthy skin and nerves B9 Red blood cells B12 Healthy nerves C Growth and repair of tis- sues Healthy bones and teeth Blood to clot Carrots, spinach, milk, eggs Whole wheat, peas, meat, beans, fish, peanuts Beets, liver, pork, turkey, fish, peanuts Liver, peas, dried beans, leafy green vegetables Meat, liver, milk, shell- fish, eggs Oranges, grapefruits, red peppers, broccoli Milk, salmon, tuna, eggs Spinach, brussels sprouts, milk, eggs D K Daily Amount Required (at ages 913 years) 600 g (1 g = 1 106 g) 0.9 mg (1 mg = 1 103 g) 12 mg 300 g 1.8 g 45 mg 5 g 60 g Some vitamins are produced in the body. For example, vitamin D is made in the skin when it is exposed to sunlight. Vitamins B12 and K are produced by bacteria that normally live inside the body. Most other vitamins must come from foods. Foods that are good sources of vitamins include whole grains, vegetables, fruits, and milk ( Table 1.1). Not getting enough vitamins can cause health problems. For example, too little vitamin C causes a disease called scurvy. People with scurvy have bleeding gums, nosebleeds, and other symptoms. Minerals are chemical elements that are needed for body processes. Minerals that you need in relatively large amounts are listed below ( Table 1.2). Minerals that you need in smaller amounts include iodine, iron, and zinc. Minerals have many important roles in the body. For example, calcium and phosphorus are needed for strong bones and teeth. Potassium and sodium are needed for muscles and nerves to work normally. Mineral Necessary for Available from Calcium Strong bones and teeth Chloride Magnesium Proper balance of water and salts in body Strong bones Phosphorus Strong bones and teeth Potassium Muscles and nerves to work normally Muscles and nerves to work normally Milk, soy milk, leafy green vegetables Table salt, most packaged foods Whole grains, leafy green vegetables, nuts Meat, poultry, whole grains Meats, grains, bananas, orange juice Table salt, most packaged foods Sodium Daily Amount Required (at ages 913 years) 1,300 mg 2.3 g 240 mg 1,250 mg 4.5 g 1.5 g Your body cannot produce any of the minerals that it needs. Instead, you must get minerals from the foods you eat. Good sources of minerals include milk, leafy green vegetables, and whole grains ( Table 1.2). Not getting enough minerals can cause health problems. For example, too little calcium may cause osteoporosis. This is a disease in which bones become soft and break easily. Getting too much of some minerals can also cause health problems. Many people get too much sodium. Sodium is added to most packaged foods. People often add more sodium to their food by using table salt. Too much sodium causes high blood pressure in some people.
|
what mineral can be found in bananas?
|
[
"potassium"
] |
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Some defenses, like your skin and mucous membranes, are not designed to ward off a specific pathogen. They are just general defenders against disease. Your body also has defenses that are more specialized. Through the help of your immune system, your body can generate an army of cells to kill that one specific pathogen. There are two different types of specific immune responses. One type involves B cells. The other type involves T cells. Recall that B cells and T cells are types of white blood cells that are key in the immune response. Whereas the immune systems first and second line of defense are more generalized or non-specific, the immune response is specific. It can be described as a specific response to a specific pathogen, meaning it uses methods to target just one pathogen at a time. These methods involve B and T cells. B cells respond to pathogens and other cells from outside the body in the blood and lymph. Most B cells fight infections by making antibodies. An antibody is a large, Y-shaped protein that binds to an antigen, a protein that is recognized as foreign. Antigens are found on the outside of bacteria, viruses and other foreign microorganisms. Each antibody can bind with just one specific type of antigen ( Figure 1.1). They fit together like a lock and key. Once an antigen and antibody bind together, they signal for a phagocyte to destroy them. Phagocytes are white blood cells that engulf targeted antigens by phagocytosis. As the antigen is on the outside of a pathogen, the pathogen is destroyed by this process. At any one time the average human body contains antibodies that can react with about 100,000,000 different antigens. This means that there can be 100,000,000 different antibody proteins in the body. There are different types of T cells, including killer T cells and helper T cells. Killer T cells destroy infected, damaged, or cancerous body cells ( Figure 1.2). When the killer T cell comes into contact with the infected cell, it releases poisons. The poisons make tiny holes in the cell membrane of the infected cell. This causes the cell to burst open. Both the infected cell and the pathogens inside it are destroyed. Helper T cells do not destroy infected or damaged body cells. But they are still necessary for an immune response. They help by releasing chemicals that control other lymphocytes. The chemicals released by helper T cells switch on both B cells and killer T cells so they can recognize and fight specific pathogens.
|
which cell will fight cancerous cells?
|
[
"killer t cell"
] |
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|
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The process of DNA replication is not always 100% accurate. Sometimes the wrong base is inserted in the new strand of DNA. This wrong base could become permanent. A permanent change in the sequence of DNA is known as a mutation. Small changes in the DNA sequence are usually point mutations, which is a change in a single nucleotide. Once DNA has a mutation, that mutation will be copied each time the DNA replicates. After cell division, each resulting cell will carry the mutation. A mutation may have no effect. However, sometimes a mutation can cause a protein to be made incorrectly. A defect in the protein can affect how well the protein works, or whether it works at all. Usually the loss of a protein function is detrimental to the organism. In rare circumstances, though, the mutation can be beneficial. Mutations are a mechanism for how species evolve. For example, suppose a mutation in an animals DNA causes the loss of an enzyme that makes a dark pigment in the animals skin. If the population of animals has moved to a light colored environment, the animals with the mutant gene would have a lighter skin color and be better camouflaged. So in this case, the mutation is beneficial. If a single base is deleted (called a deletion, which is also a point mutation), there can be huge effects on the organism, because this may cause a frameshift mutation. Remember that the bases in the mRNA are read in groups of three by the tRNA. If the reading frame is off by even one base, the resulting sequence will consist of an entirely different set of codons. The reading of an mRNA is like reading three-letter words of a sentence. Imagine the sentence: The big dog ate the red cat. If you take out the second letter from "big," the frame will be shifted so now it will read: The bgd oga tet her edc at. One single deletion makes the whole sentence impossible to read. A point mutation that adds a base (known as an insertion) would also result in a frameshift. Mutations may also occur in chromosomes ( Figure 1.1). These mutations are going to be fairly large mutations, possible affecting many genes. Possible types of mutations in chromosomes include: 1. Deletion: When a segment of DNA is lost, so there is a missing segment in the chromosome. These usually result in many genes missing from the chromosome. 2. Duplication: When a segment of DNA is repeated, creating a longer chromosome. These usually result in multiple copies of genes in the chromosome. 3. Inversion: When a segment of DNA is flipped and then reattached to the same chromosome. 4. Insertion: When a segment of DNA from one chromosome is added to another, unrelated chromosome. 5. Translocation: When two segments from different chromosomes change positions. Many mutations are not caused by errors in replication. Mutations can happen spontaneously, and they can be caused by mutagens in the environment. Some chemicals, such as those found in tobacco smoke, can be mutagens. Sometimes mutagens can also cause cancer. Tobacco smoke, for example, is often linked to lung cancer.
|
what type of mutation occurs when a segment of dna is flipped and then reattached to the same chromosome?
|
[
"inversion"
] |
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Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter. For example, the ability of iron to rust can only be observed when iron actually rusts. When it does, it combines with oxygen to become a different substance called iron oxide. Iron is very hard and silver in color, whereas iron oxide is flakey and reddish brown. Besides the ability to rust, other chemical properties include reactivity and flammability. Reactivity is the ability of matter to combine chemically with other substances. Some kinds of matter are extremely reactive; others are extremely unreactive. For example, potassium is very reactive, even with water. When a pea- sized piece of potassium is added to a small amount of water, it reacts explosively. You can observe this reaction in the video below. (Caution: Dont try this at home!) In contrast, noble gases such as helium almost never react with any other substances. Click image to the left or use the URL below. URL: Flammability is the ability of matter to burn. When matter burns, it combines with oxygen and changes to different substances. Wood is an example of flammable matter, as seen in Figure 1.1. Q: How can you tell that wood ashes are a different substance than wood? A: Ashes have different properties than wood. For example, ashes are gray and powdery, whereas wood is brown and hard. Q: What are some other substances that have the property of flammability? A: Substances called fuels have the property of flammability. They include fossil fuels such as coal, natural gas, and petroleum, as well as fuels made from petroleum, such as gasoline and kerosene. Substances made of wood, such as paper and cardboard, are also flammable.
|
which metal has the ability to rust?
|
[
"iron"
] |
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Groundwater pollutants are the same as surface water pollutants: municipal, agricultural, and industrial. Ground- water is more susceptible to some sources of pollution. For example, irrigation water infiltrates into the ground, bringing with it the pesticides, fertilizers, and herbicides that were sprayed on the fields. Water that seeps through landfills also carries toxins into the ground. Toxic substances and things like gasoline are kept in underground storage tanks; more than 100,000 of the tanks are currently leaking and many more may develop leaks. Groundwater is a bit safer from pollution than surface water from some types of pollution because some pollutants are filtered out by the rock and soil that water travels through as it travels through the ground or once it is in the aquifer. But rock and soil cant get out everything, depending on the type of rock and soil and on the types of pollutants. As it is, about 25% of the usable groundwater and 45% of the municipal groundwater supplies in the United States are polluted. When the pollutant enters the aquifer, contamination spreads in the water outward from the source and travels in the direction that the water is moving. This pollutant plume may travel very slowly, only a few inches a day, but over time can contaminate a large portion of the aquifer. Many wells that are currently in use are contaminated. In Florida, for example, more than 90% of wells have detectible contaminants and thousands have been closed.
|
this much of the municipal groundwater supplies in the united states are polluted.
|
[
"45%"
] |
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Earth is surrounded by a magnetic field (Figure 1.1) that behaves as if the planet had a gigantic bar magnet inside of it. Earths magnetic field also has a north and south pole. The magnetic field arises from the convection of molten iron and nickel metals in Earths liquid outer core. Many times during Earth history, even relatively recent Earth history, the planets magnetic field has flipped. That is, the north pole becomes the south pole and the south pole becomes the north pole. Scientists are not sure why this happens. One hypothesis is that the convection that drives the magnetic field becomes chaotic and then reverses itself. Another hypothesis is that an external event, such as an asteroid impact, disrupts motions in the core and causes the reversal. The first hypothesis is supported by computer models, but the second does not seem to be supported by much data. There is little correlation between impact events and magnetic reversals. Click image to the left or use the URL below. URL: Earths magnetic field is like a bar magnet resides in the center of the planet.
|
earths magnetic field
|
[
"has a north and south pole."
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Earth is surrounded by a magnetic field (Figure 1.1) that behaves as if the planet had a gigantic bar magnet inside of it. Earths magnetic field also has a north and south pole. The magnetic field arises from the convection of molten iron and nickel metals in Earths liquid outer core. Many times during Earth history, even relatively recent Earth history, the planets magnetic field has flipped. That is, the north pole becomes the south pole and the south pole becomes the north pole. Scientists are not sure why this happens. One hypothesis is that the convection that drives the magnetic field becomes chaotic and then reverses itself. Another hypothesis is that an external event, such as an asteroid impact, disrupts motions in the core and causes the reversal. The first hypothesis is supported by computer models, but the second does not seem to be supported by much data. There is little correlation between impact events and magnetic reversals. Click image to the left or use the URL below. URL: Earths magnetic field is like a bar magnet resides in the center of the planet.
|
the outer core is made of
|
[
"iron and nickel"
] |
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A pedigree is a chart that shows the inheritance of a trait over several generations. A pedigree is commonly created for families, and it outlines the inheritance patterns of genetic disorders and traits. A pedigree can help predict the probability that offspring will inherit a genetic disorder. Pictured below is a pedigree displaying recessive inheritance of a disorder through three generations ( Figure 1.1). From studying a pedigree, scientists can determine the following: If the trait is sex-linked (on the X or Y chromosome) or autosomal (on a chromosome that does not determine sex). If the trait is inherited in a dominant or recessive fashion. Sometimes pedigrees can also help determine whether individuals with the trait are heterozygous (two different alleles) or homozygous (two of the same allele). Some points to keep in mind when analyzing a pedigree are: 1. With autosomal recessive inheritance, all affected individuals will be homozygous recessive. 2. With dominant inheritance, all affected individuals will have at least one dominant allele. They will be either homozygous dominant or heterozygous. 3. With sex-linked inheritance, more males (XY) than females (XX) usually have the trait. Sex-linked inheritance is usually recessive.
|
in autosomal recessive inheritance, all affected individuals
|
[
"will be homozygous recessive."
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A mineral deposit that contains enough minerals to be mined for profit is called an ore. Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure 3.21 is a rock that contains minerals that are used to make aluminum. Ores have high concentrations of valuable minerals. Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. Some of the valuable deposits may be hidden underground. To find an ore deposit, geologists will go to a likely spot. They then test the physical and chemical properties of soil and rocks. Ore deposits contain valuable minerals. They may also contain other chemical elements that indicate an ore deposit is nearby. After a mineral deposit is found, geologists determine how big it is. They outline the deposit and the surrounding geology on a map. The miners calculate the amount of valuable minerals they think they will get from the deposit. The minerals will only be mined if it is profitable. If it is profitable, they must then decide on the way it should be mined. The two main methods of mining are surface mining and underground mining. Placers are a type of surface deposit. Surface mining is used to obtain mineral ores that are near the surface. Blasting breaks up the soil and rocks that contain the ore. Enormous trucks haul the broken rocks to locations where the ores can be removed. Surface mining includes open-pit mining, quarrying, and strip mining. As the name suggests, open-pit mining creates a big pit from which the ore is mined. Figure 3.22 shows an open-pit diamond mine in Russia. The size of the pit grows as long as the miners can make a profit. Strip mines are similar to open-pit mines, but the ore is removed in large strips. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings and roads. Placer minerals collect in stream gravels. They can be found in modern rivers or ancient riverbeds. California was nicknamed the Golden State. This can be traced back to the discovery of placer gold in 1848. The amount of placer gold brought in miners from around the world. The gold formed in rocks in the Sierra Nevada Mountains. The rocks also contained other valuable minerals. The gold weathered out of the hard rock. It washed downstream and then settled in gravel deposits along the river. Currently, California has active gold and silver mines. California also has mines for non-metal minerals. For example, sand and gravel are mined for construction. If an ore is deep below Earths surface it may be too expensive to remove all the rock above it. These deposits are taken by underground mining. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 m deep (that is more than 2 miles)! There are various methods of underground mining. Underground mining is more expensive than surface mining. Tunnels must be blasted into the rock so that miners and equipment can get to the ore. Underground mining is dangerous work. Fresh air and lights must be brought in to the tunnels for the miners. The miners breathe in lots of particles and dust while they are underground. The ore is drilled, blasted, or cut away from the surrounding rock and taken out of the tunnels. Sometimes there are explosions as ore is being drilled or blasted. This can lead to a mine collapse. Miners may be hurt or killed in a mining accident. Most minerals are a combination of metal and other elements. The rocks that are taken from a mine are full of valuable minerals plus rock that isnt valuable. This is called waste rock. The valuable minerals must be separated from the waste rock. One way to do this is with a chemical reaction. Chemicals are added to the ores at very high temperatures. For example, getting aluminum from waste rock uses a lot of energy. This is because temperatures greater than 900o C are needed to separate out the aluminum. It also takes a huge amount of electricity. If you recycle just 40 aluminum cans,
|
Which valuable element is found in bauxite ore?
|
[
"aluminum"
] |
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A mineral deposit that contains enough minerals to be mined for profit is called an ore. Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure 3.21 is a rock that contains minerals that are used to make aluminum. Ores have high concentrations of valuable minerals. Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. Some of the valuable deposits may be hidden underground. To find an ore deposit, geologists will go to a likely spot. They then test the physical and chemical properties of soil and rocks. Ore deposits contain valuable minerals. They may also contain other chemical elements that indicate an ore deposit is nearby. After a mineral deposit is found, geologists determine how big it is. They outline the deposit and the surrounding geology on a map. The miners calculate the amount of valuable minerals they think they will get from the deposit. The minerals will only be mined if it is profitable. If it is profitable, they must then decide on the way it should be mined. The two main methods of mining are surface mining and underground mining. Placers are a type of surface deposit. Surface mining is used to obtain mineral ores that are near the surface. Blasting breaks up the soil and rocks that contain the ore. Enormous trucks haul the broken rocks to locations where the ores can be removed. Surface mining includes open-pit mining, quarrying, and strip mining. As the name suggests, open-pit mining creates a big pit from which the ore is mined. Figure 3.22 shows an open-pit diamond mine in Russia. The size of the pit grows as long as the miners can make a profit. Strip mines are similar to open-pit mines, but the ore is removed in large strips. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings and roads. Placer minerals collect in stream gravels. They can be found in modern rivers or ancient riverbeds. California was nicknamed the Golden State. This can be traced back to the discovery of placer gold in 1848. The amount of placer gold brought in miners from around the world. The gold formed in rocks in the Sierra Nevada Mountains. The rocks also contained other valuable minerals. The gold weathered out of the hard rock. It washed downstream and then settled in gravel deposits along the river. Currently, California has active gold and silver mines. California also has mines for non-metal minerals. For example, sand and gravel are mined for construction. If an ore is deep below Earths surface it may be too expensive to remove all the rock above it. These deposits are taken by underground mining. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 m deep (that is more than 2 miles)! There are various methods of underground mining. Underground mining is more expensive than surface mining. Tunnels must be blasted into the rock so that miners and equipment can get to the ore. Underground mining is dangerous work. Fresh air and lights must be brought in to the tunnels for the miners. The miners breathe in lots of particles and dust while they are underground. The ore is drilled, blasted, or cut away from the surrounding rock and taken out of the tunnels. Sometimes there are explosions as ore is being drilled or blasted. This can lead to a mine collapse. Miners may be hurt or killed in a mining accident. Most minerals are a combination of metal and other elements. The rocks that are taken from a mine are full of valuable minerals plus rock that isnt valuable. This is called waste rock. The valuable minerals must be separated from the waste rock. One way to do this is with a chemical reaction. Chemicals are added to the ores at very high temperatures. For example, getting aluminum from waste rock uses a lot of energy. This is because temperatures greater than 900o C are needed to separate out the aluminum. It also takes a huge amount of electricity. If you recycle just 40 aluminum cans,
|
All the metals we use were originally extracted from the ground as
|
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A mineral deposit that contains enough minerals to be mined for profit is called an ore. Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure 3.21 is a rock that contains minerals that are used to make aluminum. Ores have high concentrations of valuable minerals. Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. Some of the valuable deposits may be hidden underground. To find an ore deposit, geologists will go to a likely spot. They then test the physical and chemical properties of soil and rocks. Ore deposits contain valuable minerals. They may also contain other chemical elements that indicate an ore deposit is nearby. After a mineral deposit is found, geologists determine how big it is. They outline the deposit and the surrounding geology on a map. The miners calculate the amount of valuable minerals they think they will get from the deposit. The minerals will only be mined if it is profitable. If it is profitable, they must then decide on the way it should be mined. The two main methods of mining are surface mining and underground mining. Placers are a type of surface deposit. Surface mining is used to obtain mineral ores that are near the surface. Blasting breaks up the soil and rocks that contain the ore. Enormous trucks haul the broken rocks to locations where the ores can be removed. Surface mining includes open-pit mining, quarrying, and strip mining. As the name suggests, open-pit mining creates a big pit from which the ore is mined. Figure 3.22 shows an open-pit diamond mine in Russia. The size of the pit grows as long as the miners can make a profit. Strip mines are similar to open-pit mines, but the ore is removed in large strips. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings and roads. Placer minerals collect in stream gravels. They can be found in modern rivers or ancient riverbeds. California was nicknamed the Golden State. This can be traced back to the discovery of placer gold in 1848. The amount of placer gold brought in miners from around the world. The gold formed in rocks in the Sierra Nevada Mountains. The rocks also contained other valuable minerals. The gold weathered out of the hard rock. It washed downstream and then settled in gravel deposits along the river. Currently, California has active gold and silver mines. California also has mines for non-metal minerals. For example, sand and gravel are mined for construction. If an ore is deep below Earths surface it may be too expensive to remove all the rock above it. These deposits are taken by underground mining. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 m deep (that is more than 2 miles)! There are various methods of underground mining. Underground mining is more expensive than surface mining. Tunnels must be blasted into the rock so that miners and equipment can get to the ore. Underground mining is dangerous work. Fresh air and lights must be brought in to the tunnels for the miners. The miners breathe in lots of particles and dust while they are underground. The ore is drilled, blasted, or cut away from the surrounding rock and taken out of the tunnels. Sometimes there are explosions as ore is being drilled or blasted. This can lead to a mine collapse. Miners may be hurt or killed in a mining accident. Most minerals are a combination of metal and other elements. The rocks that are taken from a mine are full of valuable minerals plus rock that isnt valuable. This is called waste rock. The valuable minerals must be separated from the waste rock. One way to do this is with a chemical reaction. Chemicals are added to the ores at very high temperatures. For example, getting aluminum from waste rock uses a lot of energy. This is because temperatures greater than 900o C are needed to separate out the aluminum. It also takes a huge amount of electricity. If you recycle just 40 aluminum cans,
|
Any rock that contains enough minerals to be mined for profit is called a(n)
|
[
"ore."
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A mineral deposit that contains enough minerals to be mined for profit is called an ore. Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure 3.21 is a rock that contains minerals that are used to make aluminum. Ores have high concentrations of valuable minerals. Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. Some of the valuable deposits may be hidden underground. To find an ore deposit, geologists will go to a likely spot. They then test the physical and chemical properties of soil and rocks. Ore deposits contain valuable minerals. They may also contain other chemical elements that indicate an ore deposit is nearby. After a mineral deposit is found, geologists determine how big it is. They outline the deposit and the surrounding geology on a map. The miners calculate the amount of valuable minerals they think they will get from the deposit. The minerals will only be mined if it is profitable. If it is profitable, they must then decide on the way it should be mined. The two main methods of mining are surface mining and underground mining. Placers are a type of surface deposit. Surface mining is used to obtain mineral ores that are near the surface. Blasting breaks up the soil and rocks that contain the ore. Enormous trucks haul the broken rocks to locations where the ores can be removed. Surface mining includes open-pit mining, quarrying, and strip mining. As the name suggests, open-pit mining creates a big pit from which the ore is mined. Figure 3.22 shows an open-pit diamond mine in Russia. The size of the pit grows as long as the miners can make a profit. Strip mines are similar to open-pit mines, but the ore is removed in large strips. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings and roads. Placer minerals collect in stream gravels. They can be found in modern rivers or ancient riverbeds. California was nicknamed the Golden State. This can be traced back to the discovery of placer gold in 1848. The amount of placer gold brought in miners from around the world. The gold formed in rocks in the Sierra Nevada Mountains. The rocks also contained other valuable minerals. The gold weathered out of the hard rock. It washed downstream and then settled in gravel deposits along the river. Currently, California has active gold and silver mines. California also has mines for non-metal minerals. For example, sand and gravel are mined for construction. If an ore is deep below Earths surface it may be too expensive to remove all the rock above it. These deposits are taken by underground mining. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 m deep (that is more than 2 miles)! There are various methods of underground mining. Underground mining is more expensive than surface mining. Tunnels must be blasted into the rock so that miners and equipment can get to the ore. Underground mining is dangerous work. Fresh air and lights must be brought in to the tunnels for the miners. The miners breathe in lots of particles and dust while they are underground. The ore is drilled, blasted, or cut away from the surrounding rock and taken out of the tunnels. Sometimes there are explosions as ore is being drilled or blasted. This can lead to a mine collapse. Miners may be hurt or killed in a mining accident. Most minerals are a combination of metal and other elements. The rocks that are taken from a mine are full of valuable minerals plus rock that isnt valuable. This is called waste rock. The valuable minerals must be separated from the waste rock. One way to do this is with a chemical reaction. Chemicals are added to the ores at very high temperatures. For example, getting aluminum from waste rock uses a lot of energy. This is because temperatures greater than 900o C are needed to separate out the aluminum. It also takes a huge amount of electricity. If you recycle just 40 aluminum cans,
|
Placer gold mined in California originally came from the
|
[
"Sierra Nevada Mountains."
] |
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A mineral deposit that contains enough minerals to be mined for profit is called an ore. Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure 3.21 is a rock that contains minerals that are used to make aluminum. Ores have high concentrations of valuable minerals. Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. Some of the valuable deposits may be hidden underground. To find an ore deposit, geologists will go to a likely spot. They then test the physical and chemical properties of soil and rocks. Ore deposits contain valuable minerals. They may also contain other chemical elements that indicate an ore deposit is nearby. After a mineral deposit is found, geologists determine how big it is. They outline the deposit and the surrounding geology on a map. The miners calculate the amount of valuable minerals they think they will get from the deposit. The minerals will only be mined if it is profitable. If it is profitable, they must then decide on the way it should be mined. The two main methods of mining are surface mining and underground mining. Placers are a type of surface deposit. Surface mining is used to obtain mineral ores that are near the surface. Blasting breaks up the soil and rocks that contain the ore. Enormous trucks haul the broken rocks to locations where the ores can be removed. Surface mining includes open-pit mining, quarrying, and strip mining. As the name suggests, open-pit mining creates a big pit from which the ore is mined. Figure 3.22 shows an open-pit diamond mine in Russia. The size of the pit grows as long as the miners can make a profit. Strip mines are similar to open-pit mines, but the ore is removed in large strips. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings and roads. Placer minerals collect in stream gravels. They can be found in modern rivers or ancient riverbeds. California was nicknamed the Golden State. This can be traced back to the discovery of placer gold in 1848. The amount of placer gold brought in miners from around the world. The gold formed in rocks in the Sierra Nevada Mountains. The rocks also contained other valuable minerals. The gold weathered out of the hard rock. It washed downstream and then settled in gravel deposits along the river. Currently, California has active gold and silver mines. California also has mines for non-metal minerals. For example, sand and gravel are mined for construction. If an ore is deep below Earths surface it may be too expensive to remove all the rock above it. These deposits are taken by underground mining. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 m deep (that is more than 2 miles)! There are various methods of underground mining. Underground mining is more expensive than surface mining. Tunnels must be blasted into the rock so that miners and equipment can get to the ore. Underground mining is dangerous work. Fresh air and lights must be brought in to the tunnels for the miners. The miners breathe in lots of particles and dust while they are underground. The ore is drilled, blasted, or cut away from the surrounding rock and taken out of the tunnels. Sometimes there are explosions as ore is being drilled or blasted. This can lead to a mine collapse. Miners may be hurt or killed in a mining accident. Most minerals are a combination of metal and other elements. The rocks that are taken from a mine are full of valuable minerals plus rock that isnt valuable. This is called waste rock. The valuable minerals must be separated from the waste rock. One way to do this is with a chemical reaction. Chemicals are added to the ores at very high temperatures. For example, getting aluminum from waste rock uses a lot of energy. This is because temperatures greater than 900o C are needed to separate out the aluminum. It also takes a huge amount of electricity. If you recycle just 40 aluminum cans,
|
type of ore that is mined to make aluminum
|
[
"bauxite"
] |
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A mineral deposit that contains enough minerals to be mined for profit is called an ore. Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure 3.21 is a rock that contains minerals that are used to make aluminum. Ores have high concentrations of valuable minerals. Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. Some of the valuable deposits may be hidden underground. To find an ore deposit, geologists will go to a likely spot. They then test the physical and chemical properties of soil and rocks. Ore deposits contain valuable minerals. They may also contain other chemical elements that indicate an ore deposit is nearby. After a mineral deposit is found, geologists determine how big it is. They outline the deposit and the surrounding geology on a map. The miners calculate the amount of valuable minerals they think they will get from the deposit. The minerals will only be mined if it is profitable. If it is profitable, they must then decide on the way it should be mined. The two main methods of mining are surface mining and underground mining. Placers are a type of surface deposit. Surface mining is used to obtain mineral ores that are near the surface. Blasting breaks up the soil and rocks that contain the ore. Enormous trucks haul the broken rocks to locations where the ores can be removed. Surface mining includes open-pit mining, quarrying, and strip mining. As the name suggests, open-pit mining creates a big pit from which the ore is mined. Figure 3.22 shows an open-pit diamond mine in Russia. The size of the pit grows as long as the miners can make a profit. Strip mines are similar to open-pit mines, but the ore is removed in large strips. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings and roads. Placer minerals collect in stream gravels. They can be found in modern rivers or ancient riverbeds. California was nicknamed the Golden State. This can be traced back to the discovery of placer gold in 1848. The amount of placer gold brought in miners from around the world. The gold formed in rocks in the Sierra Nevada Mountains. The rocks also contained other valuable minerals. The gold weathered out of the hard rock. It washed downstream and then settled in gravel deposits along the river. Currently, California has active gold and silver mines. California also has mines for non-metal minerals. For example, sand and gravel are mined for construction. If an ore is deep below Earths surface it may be too expensive to remove all the rock above it. These deposits are taken by underground mining. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 m deep (that is more than 2 miles)! There are various methods of underground mining. Underground mining is more expensive than surface mining. Tunnels must be blasted into the rock so that miners and equipment can get to the ore. Underground mining is dangerous work. Fresh air and lights must be brought in to the tunnels for the miners. The miners breathe in lots of particles and dust while they are underground. The ore is drilled, blasted, or cut away from the surrounding rock and taken out of the tunnels. Sometimes there are explosions as ore is being drilled or blasted. This can lead to a mine collapse. Miners may be hurt or killed in a mining accident. Most minerals are a combination of metal and other elements. The rocks that are taken from a mine are full of valuable minerals plus rock that isnt valuable. This is called waste rock. The valuable minerals must be separated from the waste rock. One way to do this is with a chemical reaction. Chemicals are added to the ores at very high temperatures. For example, getting aluminum from waste rock uses a lot of energy. This is because temperatures greater than 900o C are needed to separate out the aluminum. It also takes a huge amount of electricity. If you recycle just 40 aluminum cans,
|
any rock that contains a concentration of valuable minerals
|
[
"ore"
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A mineral deposit that contains enough minerals to be mined for profit is called an ore. Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure 3.21 is a rock that contains minerals that are used to make aluminum. Ores have high concentrations of valuable minerals. Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. Some of the valuable deposits may be hidden underground. To find an ore deposit, geologists will go to a likely spot. They then test the physical and chemical properties of soil and rocks. Ore deposits contain valuable minerals. They may also contain other chemical elements that indicate an ore deposit is nearby. After a mineral deposit is found, geologists determine how big it is. They outline the deposit and the surrounding geology on a map. The miners calculate the amount of valuable minerals they think they will get from the deposit. The minerals will only be mined if it is profitable. If it is profitable, they must then decide on the way it should be mined. The two main methods of mining are surface mining and underground mining. Placers are a type of surface deposit. Surface mining is used to obtain mineral ores that are near the surface. Blasting breaks up the soil and rocks that contain the ore. Enormous trucks haul the broken rocks to locations where the ores can be removed. Surface mining includes open-pit mining, quarrying, and strip mining. As the name suggests, open-pit mining creates a big pit from which the ore is mined. Figure 3.22 shows an open-pit diamond mine in Russia. The size of the pit grows as long as the miners can make a profit. Strip mines are similar to open-pit mines, but the ore is removed in large strips. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings and roads. Placer minerals collect in stream gravels. They can be found in modern rivers or ancient riverbeds. California was nicknamed the Golden State. This can be traced back to the discovery of placer gold in 1848. The amount of placer gold brought in miners from around the world. The gold formed in rocks in the Sierra Nevada Mountains. The rocks also contained other valuable minerals. The gold weathered out of the hard rock. It washed downstream and then settled in gravel deposits along the river. Currently, California has active gold and silver mines. California also has mines for non-metal minerals. For example, sand and gravel are mined for construction. If an ore is deep below Earths surface it may be too expensive to remove all the rock above it. These deposits are taken by underground mining. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 m deep (that is more than 2 miles)! There are various methods of underground mining. Underground mining is more expensive than surface mining. Tunnels must be blasted into the rock so that miners and equipment can get to the ore. Underground mining is dangerous work. Fresh air and lights must be brought in to the tunnels for the miners. The miners breathe in lots of particles and dust while they are underground. The ore is drilled, blasted, or cut away from the surrounding rock and taken out of the tunnels. Sometimes there are explosions as ore is being drilled or blasted. This can lead to a mine collapse. Miners may be hurt or killed in a mining accident. Most minerals are a combination of metal and other elements. The rocks that are taken from a mine are full of valuable minerals plus rock that isnt valuable. This is called waste rock. The valuable minerals must be separated from the waste rock. One way to do this is with a chemical reaction. Chemicals are added to the ores at very high temperatures. For example, getting aluminum from waste rock uses a lot of energy. This is because temperatures greater than 900o C are needed to separate out the aluminum. It also takes a huge amount of electricity. If you recycle just 40 aluminum cans,
|
type of open-pit mine that produces rocks and minerals for buildings and roads
|
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A mineral deposit that contains enough minerals to be mined for profit is called an ore. Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure 3.21 is a rock that contains minerals that are used to make aluminum. Ores have high concentrations of valuable minerals. Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. Some of the valuable deposits may be hidden underground. To find an ore deposit, geologists will go to a likely spot. They then test the physical and chemical properties of soil and rocks. Ore deposits contain valuable minerals. They may also contain other chemical elements that indicate an ore deposit is nearby. After a mineral deposit is found, geologists determine how big it is. They outline the deposit and the surrounding geology on a map. The miners calculate the amount of valuable minerals they think they will get from the deposit. The minerals will only be mined if it is profitable. If it is profitable, they must then decide on the way it should be mined. The two main methods of mining are surface mining and underground mining. Placers are a type of surface deposit. Surface mining is used to obtain mineral ores that are near the surface. Blasting breaks up the soil and rocks that contain the ore. Enormous trucks haul the broken rocks to locations where the ores can be removed. Surface mining includes open-pit mining, quarrying, and strip mining. As the name suggests, open-pit mining creates a big pit from which the ore is mined. Figure 3.22 shows an open-pit diamond mine in Russia. The size of the pit grows as long as the miners can make a profit. Strip mines are similar to open-pit mines, but the ore is removed in large strips. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings and roads. Placer minerals collect in stream gravels. They can be found in modern rivers or ancient riverbeds. California was nicknamed the Golden State. This can be traced back to the discovery of placer gold in 1848. The amount of placer gold brought in miners from around the world. The gold formed in rocks in the Sierra Nevada Mountains. The rocks also contained other valuable minerals. The gold weathered out of the hard rock. It washed downstream and then settled in gravel deposits along the river. Currently, California has active gold and silver mines. California also has mines for non-metal minerals. For example, sand and gravel are mined for construction. If an ore is deep below Earths surface it may be too expensive to remove all the rock above it. These deposits are taken by underground mining. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 m deep (that is more than 2 miles)! There are various methods of underground mining. Underground mining is more expensive than surface mining. Tunnels must be blasted into the rock so that miners and equipment can get to the ore. Underground mining is dangerous work. Fresh air and lights must be brought in to the tunnels for the miners. The miners breathe in lots of particles and dust while they are underground. The ore is drilled, blasted, or cut away from the surrounding rock and taken out of the tunnels. Sometimes there are explosions as ore is being drilled or blasted. This can lead to a mine collapse. Miners may be hurt or killed in a mining accident. Most minerals are a combination of metal and other elements. The rocks that are taken from a mine are full of valuable minerals plus rock that isnt valuable. This is called waste rock. The valuable minerals must be separated from the waste rock. One way to do this is with a chemical reaction. Chemicals are added to the ores at very high temperatures. For example, getting aluminum from waste rock uses a lot of energy. This is because temperatures greater than 900o C are needed to separate out the aluminum. It also takes a huge amount of electricity. If you recycle just 40 aluminum cans,
|
type of mineral deposit that collects in stream gravel
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A mineral deposit that contains enough minerals to be mined for profit is called an ore. Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure 3.21 is a rock that contains minerals that are used to make aluminum. Ores have high concentrations of valuable minerals. Certain places on Earth are more likely to have certain ores. Geologists search for the places that might have ore deposits. Some of the valuable deposits may be hidden underground. To find an ore deposit, geologists will go to a likely spot. They then test the physical and chemical properties of soil and rocks. Ore deposits contain valuable minerals. They may also contain other chemical elements that indicate an ore deposit is nearby. After a mineral deposit is found, geologists determine how big it is. They outline the deposit and the surrounding geology on a map. The miners calculate the amount of valuable minerals they think they will get from the deposit. The minerals will only be mined if it is profitable. If it is profitable, they must then decide on the way it should be mined. The two main methods of mining are surface mining and underground mining. Placers are a type of surface deposit. Surface mining is used to obtain mineral ores that are near the surface. Blasting breaks up the soil and rocks that contain the ore. Enormous trucks haul the broken rocks to locations where the ores can be removed. Surface mining includes open-pit mining, quarrying, and strip mining. As the name suggests, open-pit mining creates a big pit from which the ore is mined. Figure 3.22 shows an open-pit diamond mine in Russia. The size of the pit grows as long as the miners can make a profit. Strip mines are similar to open-pit mines, but the ore is removed in large strips. A quarry is a type of open-pit mine that produces rocks and minerals that are used to make buildings and roads. Placer minerals collect in stream gravels. They can be found in modern rivers or ancient riverbeds. California was nicknamed the Golden State. This can be traced back to the discovery of placer gold in 1848. The amount of placer gold brought in miners from around the world. The gold formed in rocks in the Sierra Nevada Mountains. The rocks also contained other valuable minerals. The gold weathered out of the hard rock. It washed downstream and then settled in gravel deposits along the river. Currently, California has active gold and silver mines. California also has mines for non-metal minerals. For example, sand and gravel are mined for construction. If an ore is deep below Earths surface it may be too expensive to remove all the rock above it. These deposits are taken by underground mining. Underground mines can be very deep. The deepest gold mine in South Africa is more than 3,700 m deep (that is more than 2 miles)! There are various methods of underground mining. Underground mining is more expensive than surface mining. Tunnels must be blasted into the rock so that miners and equipment can get to the ore. Underground mining is dangerous work. Fresh air and lights must be brought in to the tunnels for the miners. The miners breathe in lots of particles and dust while they are underground. The ore is drilled, blasted, or cut away from the surrounding rock and taken out of the tunnels. Sometimes there are explosions as ore is being drilled or blasted. This can lead to a mine collapse. Miners may be hurt or killed in a mining accident. Most minerals are a combination of metal and other elements. The rocks that are taken from a mine are full of valuable minerals plus rock that isnt valuable. This is called waste rock. The valuable minerals must be separated from the waste rock. One way to do this is with a chemical reaction. Chemicals are added to the ores at very high temperatures. For example, getting aluminum from waste rock uses a lot of energy. This is because temperatures greater than 900o C are needed to separate out the aluminum. It also takes a huge amount of electricity. If you recycle just 40 aluminum cans,
|
general name for mining methods that include open-pit mining and strip mining
|
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The rate at which a device changes electric current to another form of energy is called electric power. The SI unit for powerincluding electric poweris the watt. A watt equals 1 joule of energy per second. High wattages are often expressed in kilowatts, where 1 kilowatt equals 1000 watts. The power of an electric device, such as a hair dryer, can be calculated if you know the voltage of the circuit and how much current the device receives. The following equation is used: Power (watts) = Current (amps) Voltage (volts) Assume that Mirandas hair dryer is the only electric device in a 120-volt circuit that carries 15 amps of current. Then the power of her hair dryer in kilowatts is: Power = 15 amps 120 volts = 1800 watts, or 1.8 kilowatts Q: If a different hair dryer is plugged into a 120-volt circuit that carries 10 amps of current. What is the power of the other hair dryer? A: Substitute these values in the power equation: Power = 10 amps 120 volts = 1200 watts, or 1.2 kilowatts Did you ever wonder how much electrical energy it takes to use an appliance such as a hair dryer? Electrical energy use depends on the power of the appliance and how long it is used. It can be calculated with this equation: Electrical Energy = Power Time If Miranda uses her 1.8-kilowatt hair dryer for 0.2 hours, how much electrical energy does she use? Electrical Energy = 1.8 kilowatts 0.2 hours = 0.36 kilowatt-hours Electrical energy use is typically expressed in kilowatt-hours, as in this example. How much energy is this? One kilowatt-hour equals 3.6 million joules of energy. Q: Suppose Miranda were to use a 1.2-kilowatt hair dryer for 0.2 hours. How much electrical energy would she use then? A: She would use: Electrical Energy = 1.2 kilowatts 0.2 hour = 0.24 kilowatt-hours
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if an electric device in a 120-volt circuit uses 10 amps of current, then the power of the device is
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Look at the circle graph in the Figure 1.1. It shows that oil is the single most commonly used energy resource in the U.S., followed by natural gas, and then by coal. All of these energy resources are nonrenewable. Nonrenewable resources are resources that are limited in supply and cannot be replaced as quickly as they are used up. Renewable resources, in contrast, provide only 8 percent of all energy used in the U.S. Renewable resources are natural resources that can be replaced in a relatively short period of time or are virtually limitless in supply. They include solar energy from sunlight, geothermal energy from under Earths surface, wind, biomass (from once-living things or their wastes), and hydropower (from running water). People in the U.S. use far more energyespecially energy from oilthan people in any other nation. The bar graph in the Figure 1.2 compares the amount of oil used by the top ten oil-using nations. The U.S. uses more oil than several other top-ten countries combined. If you also consider the population size in these countries, the differences are even more stunning. The average person in the U.S. uses a whopping 23 barrels of oil a year! In comparison, the average person in India or China uses just 1 or 2 barrels of oil a year. Q: How does the use of oil and other fossil fuels relate to pollution? A: Greater use of oil and other fossil fuels causes more pollution.
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the most commonly used energy resource in the u.s. is
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Imagine a huge bar magnet passing through Earths axis, as in the Figure 1.1. This is a good representation of Earth as a magnet. Like a bar magnet, Earth has north and south magnetic poles. A magnetic pole is the north or south end of a magnet, where the magnet exerts the most force. Although the needle of a compass always points north, it doesnt point to Earths north geographic pole. Find the north geographic pole in the Figure 1.2. As you can see, it is located at 90 north latitude. Where does a compass Q: The north end of a compass needle points toward Earths north magnetic pole. The like poles of two magnets repel each other, and the opposite poles attract. So why doesnt the north end of a compass needle point to Earths south magnetic pole instead? A: The answer may surprise you. The compass needle actually does point to the south pole of magnet Earth. However, it is called the north magnetic pole because it is close to the north geographic pole. This naming convention was adopted a long time ago to avoid confusion. Like all magnets, Earth has a magnetic field. Earths magnetic field is called the magnetosphere. You can see a model of the magnetosphere in the Figure 1.3. It is a huge region that extends outward from Earth in all directions. Earth exerts magnetic force over the entire field, but the force is strongest at the poles, where lines of force converge. Click image to the left or use the URL below. URL:
|
which shape of magnet does magnet earth resemble?
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Elements form compounds when they combine chemically. Their atoms join together to form molecules, crystals, or other structures. The atoms are held together by chemical bonds. A chemical bond is a force of attraction between atoms or ions. It occurs when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom. You can learn more about chemical bonds in this video: MEDIA Click image to the left or use the URL below. URL: Look at the example of water in Figure 7.1. A water molecule consists of two atoms of hydrogen and one atom of oxygen. Each hydrogen atom has just one electron. The oxygen atom has six valence electrons. In a water molecule, two hydrogen atoms share their two electrons with the six valence electrons of one oxygen atom. By sharing electrons, each atom has electrons available to fill its sole or outer energy level. This gives it a more stable arrangement of electrons that takes less energy to maintain. Water (H2 O) is an example of a chemical compound. Water molecules always consist of two atoms of hydrogen and one atom of oxygen. Like water, all other chemical compounds consist of a fixed ratio of elements. It doesnt matter how much or how little of a compound there is. It always has the same composition. Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table 7.1 shows some other examples of compounds and their chemical formulas. Name of Compound Electron Dot Diagram Numbers of Atoms Chemical Formula Name of Compound Hydrogen chloride Electron Dot Diagram Numbers of Atoms H=1 Cl = 1 Chemical Formula HCl Methane C=1 H=4 CH4 Hydrogen peroxide H=2 O=2 H2 O2 Carbon dioxide C=1 O=2 CO2 Problem Solving Problem: A molecule of ammonia consists of one atom of nitrogen (N) and three atoms of hydrogen (H). What is its chemical formula? Solution: The chemical formula is NH3 . You Try It! Problem: A molecule of nitrogen dioxide consists of one atom of nitrogen (N) and two atoms of oxygen (O). What is its chemical formula? The same elements may combine in different ratios. If they do, they form different compounds. Figure 7.2 shows some examples. Both water (H2 O) and hydrogen peroxide (H2 O2 ) consist of hydrogen and oxygen. However, they have different ratios of the two elements. As a result, water and hydrogen peroxide are different compounds with different properties. If youve ever used hydrogen peroxide to disinfect a cut, then you know that it is very different from water! Both carbon dioxide (CO2 ) and carbon monoxide (CO) consist of carbon and oxygen, but in different ratios. How do their properties differ? There are different types of compounds. They differ in the nature of the bonds that hold their atoms together. The type of bonds in a compound determines many of its properties. Three types of bonds are ionic, covalent, and metallic bonds. You will read about these three types in later lessons. You can also learn more about them by watching this video: (7:18). MEDIA Click image to the left or use the URL below. URL: Chocolate: Its been revered for millennia by cultures throughout the world. But while its easy to appreciate all of its delicious forms, creating this confection is a complex culinary feat. Local chocolate makers explain the elaborate engineering and chemistry behind this tasty treat. And learn why its actually good for your health! For more information on the science of chocolate, see http://science.kqed.org/quest/video/the-sweet-science-of-chocolate/ . MEDIA Click image to the left or use the URL below. URL:
|
There are millions of unique substances in the universe because elements can combine in many different ways to form
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Elements form compounds when they combine chemically. Their atoms join together to form molecules, crystals, or other structures. The atoms are held together by chemical bonds. A chemical bond is a force of attraction between atoms or ions. It occurs when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom. You can learn more about chemical bonds in this video: MEDIA Click image to the left or use the URL below. URL: Look at the example of water in Figure 7.1. A water molecule consists of two atoms of hydrogen and one atom of oxygen. Each hydrogen atom has just one electron. The oxygen atom has six valence electrons. In a water molecule, two hydrogen atoms share their two electrons with the six valence electrons of one oxygen atom. By sharing electrons, each atom has electrons available to fill its sole or outer energy level. This gives it a more stable arrangement of electrons that takes less energy to maintain. Water (H2 O) is an example of a chemical compound. Water molecules always consist of two atoms of hydrogen and one atom of oxygen. Like water, all other chemical compounds consist of a fixed ratio of elements. It doesnt matter how much or how little of a compound there is. It always has the same composition. Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table 7.1 shows some other examples of compounds and their chemical formulas. Name of Compound Electron Dot Diagram Numbers of Atoms Chemical Formula Name of Compound Hydrogen chloride Electron Dot Diagram Numbers of Atoms H=1 Cl = 1 Chemical Formula HCl Methane C=1 H=4 CH4 Hydrogen peroxide H=2 O=2 H2 O2 Carbon dioxide C=1 O=2 CO2 Problem Solving Problem: A molecule of ammonia consists of one atom of nitrogen (N) and three atoms of hydrogen (H). What is its chemical formula? Solution: The chemical formula is NH3 . You Try It! Problem: A molecule of nitrogen dioxide consists of one atom of nitrogen (N) and two atoms of oxygen (O). What is its chemical formula? The same elements may combine in different ratios. If they do, they form different compounds. Figure 7.2 shows some examples. Both water (H2 O) and hydrogen peroxide (H2 O2 ) consist of hydrogen and oxygen. However, they have different ratios of the two elements. As a result, water and hydrogen peroxide are different compounds with different properties. If youve ever used hydrogen peroxide to disinfect a cut, then you know that it is very different from water! Both carbon dioxide (CO2 ) and carbon monoxide (CO) consist of carbon and oxygen, but in different ratios. How do their properties differ? There are different types of compounds. They differ in the nature of the bonds that hold their atoms together. The type of bonds in a compound determines many of its properties. Three types of bonds are ionic, covalent, and metallic bonds. You will read about these three types in later lessons. You can also learn more about them by watching this video: (7:18). MEDIA Click image to the left or use the URL below. URL: Chocolate: Its been revered for millennia by cultures throughout the world. But while its easy to appreciate all of its delicious forms, creating this confection is a complex culinary feat. Local chocolate makers explain the elaborate engineering and chemistry behind this tasty treat. And learn why its actually good for your health! For more information on the science of chocolate, see http://science.kqed.org/quest/video/the-sweet-science-of-chocolate/ . MEDIA Click image to the left or use the URL below. URL:
|
The chemical formula HCl represents the compound named
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Elements form compounds when they combine chemically. Their atoms join together to form molecules, crystals, or other structures. The atoms are held together by chemical bonds. A chemical bond is a force of attraction between atoms or ions. It occurs when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom. You can learn more about chemical bonds in this video: MEDIA Click image to the left or use the URL below. URL: Look at the example of water in Figure 7.1. A water molecule consists of two atoms of hydrogen and one atom of oxygen. Each hydrogen atom has just one electron. The oxygen atom has six valence electrons. In a water molecule, two hydrogen atoms share their two electrons with the six valence electrons of one oxygen atom. By sharing electrons, each atom has electrons available to fill its sole or outer energy level. This gives it a more stable arrangement of electrons that takes less energy to maintain. Water (H2 O) is an example of a chemical compound. Water molecules always consist of two atoms of hydrogen and one atom of oxygen. Like water, all other chemical compounds consist of a fixed ratio of elements. It doesnt matter how much or how little of a compound there is. It always has the same composition. Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table 7.1 shows some other examples of compounds and their chemical formulas. Name of Compound Electron Dot Diagram Numbers of Atoms Chemical Formula Name of Compound Hydrogen chloride Electron Dot Diagram Numbers of Atoms H=1 Cl = 1 Chemical Formula HCl Methane C=1 H=4 CH4 Hydrogen peroxide H=2 O=2 H2 O2 Carbon dioxide C=1 O=2 CO2 Problem Solving Problem: A molecule of ammonia consists of one atom of nitrogen (N) and three atoms of hydrogen (H). What is its chemical formula? Solution: The chemical formula is NH3 . You Try It! Problem: A molecule of nitrogen dioxide consists of one atom of nitrogen (N) and two atoms of oxygen (O). What is its chemical formula? The same elements may combine in different ratios. If they do, they form different compounds. Figure 7.2 shows some examples. Both water (H2 O) and hydrogen peroxide (H2 O2 ) consist of hydrogen and oxygen. However, they have different ratios of the two elements. As a result, water and hydrogen peroxide are different compounds with different properties. If youve ever used hydrogen peroxide to disinfect a cut, then you know that it is very different from water! Both carbon dioxide (CO2 ) and carbon monoxide (CO) consist of carbon and oxygen, but in different ratios. How do their properties differ? There are different types of compounds. They differ in the nature of the bonds that hold their atoms together. The type of bonds in a compound determines many of its properties. Three types of bonds are ionic, covalent, and metallic bonds. You will read about these three types in later lessons. You can also learn more about them by watching this video: (7:18). MEDIA Click image to the left or use the URL below. URL: Chocolate: Its been revered for millennia by cultures throughout the world. But while its easy to appreciate all of its delicious forms, creating this confection is a complex culinary feat. Local chocolate makers explain the elaborate engineering and chemistry behind this tasty treat. And learn why its actually good for your health! For more information on the science of chocolate, see http://science.kqed.org/quest/video/the-sweet-science-of-chocolate/ . MEDIA Click image to the left or use the URL below. URL:
|
Chemical bonds always involve
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Elements form compounds when they combine chemically. Their atoms join together to form molecules, crystals, or other structures. The atoms are held together by chemical bonds. A chemical bond is a force of attraction between atoms or ions. It occurs when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom. You can learn more about chemical bonds in this video: MEDIA Click image to the left or use the URL below. URL: Look at the example of water in Figure 7.1. A water molecule consists of two atoms of hydrogen and one atom of oxygen. Each hydrogen atom has just one electron. The oxygen atom has six valence electrons. In a water molecule, two hydrogen atoms share their two electrons with the six valence electrons of one oxygen atom. By sharing electrons, each atom has electrons available to fill its sole or outer energy level. This gives it a more stable arrangement of electrons that takes less energy to maintain. Water (H2 O) is an example of a chemical compound. Water molecules always consist of two atoms of hydrogen and one atom of oxygen. Like water, all other chemical compounds consist of a fixed ratio of elements. It doesnt matter how much or how little of a compound there is. It always has the same composition. Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table 7.1 shows some other examples of compounds and their chemical formulas. Name of Compound Electron Dot Diagram Numbers of Atoms Chemical Formula Name of Compound Hydrogen chloride Electron Dot Diagram Numbers of Atoms H=1 Cl = 1 Chemical Formula HCl Methane C=1 H=4 CH4 Hydrogen peroxide H=2 O=2 H2 O2 Carbon dioxide C=1 O=2 CO2 Problem Solving Problem: A molecule of ammonia consists of one atom of nitrogen (N) and three atoms of hydrogen (H). What is its chemical formula? Solution: The chemical formula is NH3 . You Try It! Problem: A molecule of nitrogen dioxide consists of one atom of nitrogen (N) and two atoms of oxygen (O). What is its chemical formula? The same elements may combine in different ratios. If they do, they form different compounds. Figure 7.2 shows some examples. Both water (H2 O) and hydrogen peroxide (H2 O2 ) consist of hydrogen and oxygen. However, they have different ratios of the two elements. As a result, water and hydrogen peroxide are different compounds with different properties. If youve ever used hydrogen peroxide to disinfect a cut, then you know that it is very different from water! Both carbon dioxide (CO2 ) and carbon monoxide (CO) consist of carbon and oxygen, but in different ratios. How do their properties differ? There are different types of compounds. They differ in the nature of the bonds that hold their atoms together. The type of bonds in a compound determines many of its properties. Three types of bonds are ionic, covalent, and metallic bonds. You will read about these three types in later lessons. You can also learn more about them by watching this video: (7:18). MEDIA Click image to the left or use the URL below. URL: Chocolate: Its been revered for millennia by cultures throughout the world. But while its easy to appreciate all of its delicious forms, creating this confection is a complex culinary feat. Local chocolate makers explain the elaborate engineering and chemistry behind this tasty treat. And learn why its actually good for your health! For more information on the science of chocolate, see http://science.kqed.org/quest/video/the-sweet-science-of-chocolate/ . MEDIA Click image to the left or use the URL below. URL:
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pure substance that cannot be separated into any other substances
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Elements form compounds when they combine chemically. Their atoms join together to form molecules, crystals, or other structures. The atoms are held together by chemical bonds. A chemical bond is a force of attraction between atoms or ions. It occurs when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom. You can learn more about chemical bonds in this video: MEDIA Click image to the left or use the URL below. URL: Look at the example of water in Figure 7.1. A water molecule consists of two atoms of hydrogen and one atom of oxygen. Each hydrogen atom has just one electron. The oxygen atom has six valence electrons. In a water molecule, two hydrogen atoms share their two electrons with the six valence electrons of one oxygen atom. By sharing electrons, each atom has electrons available to fill its sole or outer energy level. This gives it a more stable arrangement of electrons that takes less energy to maintain. Water (H2 O) is an example of a chemical compound. Water molecules always consist of two atoms of hydrogen and one atom of oxygen. Like water, all other chemical compounds consist of a fixed ratio of elements. It doesnt matter how much or how little of a compound there is. It always has the same composition. Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table 7.1 shows some other examples of compounds and their chemical formulas. Name of Compound Electron Dot Diagram Numbers of Atoms Chemical Formula Name of Compound Hydrogen chloride Electron Dot Diagram Numbers of Atoms H=1 Cl = 1 Chemical Formula HCl Methane C=1 H=4 CH4 Hydrogen peroxide H=2 O=2 H2 O2 Carbon dioxide C=1 O=2 CO2 Problem Solving Problem: A molecule of ammonia consists of one atom of nitrogen (N) and three atoms of hydrogen (H). What is its chemical formula? Solution: The chemical formula is NH3 . You Try It! Problem: A molecule of nitrogen dioxide consists of one atom of nitrogen (N) and two atoms of oxygen (O). What is its chemical formula? The same elements may combine in different ratios. If they do, they form different compounds. Figure 7.2 shows some examples. Both water (H2 O) and hydrogen peroxide (H2 O2 ) consist of hydrogen and oxygen. However, they have different ratios of the two elements. As a result, water and hydrogen peroxide are different compounds with different properties. If youve ever used hydrogen peroxide to disinfect a cut, then you know that it is very different from water! Both carbon dioxide (CO2 ) and carbon monoxide (CO) consist of carbon and oxygen, but in different ratios. How do their properties differ? There are different types of compounds. They differ in the nature of the bonds that hold their atoms together. The type of bonds in a compound determines many of its properties. Three types of bonds are ionic, covalent, and metallic bonds. You will read about these three types in later lessons. You can also learn more about them by watching this video: (7:18). MEDIA Click image to the left or use the URL below. URL: Chocolate: Its been revered for millennia by cultures throughout the world. But while its easy to appreciate all of its delicious forms, creating this confection is a complex culinary feat. Local chocolate makers explain the elaborate engineering and chemistry behind this tasty treat. And learn why its actually good for your health! For more information on the science of chocolate, see http://science.kqed.org/quest/video/the-sweet-science-of-chocolate/ . MEDIA Click image to the left or use the URL below. URL:
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Elements form compounds when they combine chemically. Their atoms join together to form molecules, crystals, or other structures. The atoms are held together by chemical bonds. A chemical bond is a force of attraction between atoms or ions. It occurs when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom. You can learn more about chemical bonds in this video: MEDIA Click image to the left or use the URL below. URL: Look at the example of water in Figure 7.1. A water molecule consists of two atoms of hydrogen and one atom of oxygen. Each hydrogen atom has just one electron. The oxygen atom has six valence electrons. In a water molecule, two hydrogen atoms share their two electrons with the six valence electrons of one oxygen atom. By sharing electrons, each atom has electrons available to fill its sole or outer energy level. This gives it a more stable arrangement of electrons that takes less energy to maintain. Water (H2 O) is an example of a chemical compound. Water molecules always consist of two atoms of hydrogen and one atom of oxygen. Like water, all other chemical compounds consist of a fixed ratio of elements. It doesnt matter how much or how little of a compound there is. It always has the same composition. Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table 7.1 shows some other examples of compounds and their chemical formulas. Name of Compound Electron Dot Diagram Numbers of Atoms Chemical Formula Name of Compound Hydrogen chloride Electron Dot Diagram Numbers of Atoms H=1 Cl = 1 Chemical Formula HCl Methane C=1 H=4 CH4 Hydrogen peroxide H=2 O=2 H2 O2 Carbon dioxide C=1 O=2 CO2 Problem Solving Problem: A molecule of ammonia consists of one atom of nitrogen (N) and three atoms of hydrogen (H). What is its chemical formula? Solution: The chemical formula is NH3 . You Try It! Problem: A molecule of nitrogen dioxide consists of one atom of nitrogen (N) and two atoms of oxygen (O). What is its chemical formula? The same elements may combine in different ratios. If they do, they form different compounds. Figure 7.2 shows some examples. Both water (H2 O) and hydrogen peroxide (H2 O2 ) consist of hydrogen and oxygen. However, they have different ratios of the two elements. As a result, water and hydrogen peroxide are different compounds with different properties. If youve ever used hydrogen peroxide to disinfect a cut, then you know that it is very different from water! Both carbon dioxide (CO2 ) and carbon monoxide (CO) consist of carbon and oxygen, but in different ratios. How do their properties differ? There are different types of compounds. They differ in the nature of the bonds that hold their atoms together. The type of bonds in a compound determines many of its properties. Three types of bonds are ionic, covalent, and metallic bonds. You will read about these three types in later lessons. You can also learn more about them by watching this video: (7:18). MEDIA Click image to the left or use the URL below. URL: Chocolate: Its been revered for millennia by cultures throughout the world. But while its easy to appreciate all of its delicious forms, creating this confection is a complex culinary feat. Local chocolate makers explain the elaborate engineering and chemistry behind this tasty treat. And learn why its actually good for your health! For more information on the science of chocolate, see http://science.kqed.org/quest/video/the-sweet-science-of-chocolate/ . MEDIA Click image to the left or use the URL below. URL:
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Elements form compounds when they combine chemically. Their atoms join together to form molecules, crystals, or other structures. The atoms are held together by chemical bonds. A chemical bond is a force of attraction between atoms or ions. It occurs when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom. You can learn more about chemical bonds in this video: MEDIA Click image to the left or use the URL below. URL: Look at the example of water in Figure 7.1. A water molecule consists of two atoms of hydrogen and one atom of oxygen. Each hydrogen atom has just one electron. The oxygen atom has six valence electrons. In a water molecule, two hydrogen atoms share their two electrons with the six valence electrons of one oxygen atom. By sharing electrons, each atom has electrons available to fill its sole or outer energy level. This gives it a more stable arrangement of electrons that takes less energy to maintain. Water (H2 O) is an example of a chemical compound. Water molecules always consist of two atoms of hydrogen and one atom of oxygen. Like water, all other chemical compounds consist of a fixed ratio of elements. It doesnt matter how much or how little of a compound there is. It always has the same composition. Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table 7.1 shows some other examples of compounds and their chemical formulas. Name of Compound Electron Dot Diagram Numbers of Atoms Chemical Formula Name of Compound Hydrogen chloride Electron Dot Diagram Numbers of Atoms H=1 Cl = 1 Chemical Formula HCl Methane C=1 H=4 CH4 Hydrogen peroxide H=2 O=2 H2 O2 Carbon dioxide C=1 O=2 CO2 Problem Solving Problem: A molecule of ammonia consists of one atom of nitrogen (N) and three atoms of hydrogen (H). What is its chemical formula? Solution: The chemical formula is NH3 . You Try It! Problem: A molecule of nitrogen dioxide consists of one atom of nitrogen (N) and two atoms of oxygen (O). What is its chemical formula? The same elements may combine in different ratios. If they do, they form different compounds. Figure 7.2 shows some examples. Both water (H2 O) and hydrogen peroxide (H2 O2 ) consist of hydrogen and oxygen. However, they have different ratios of the two elements. As a result, water and hydrogen peroxide are different compounds with different properties. If youve ever used hydrogen peroxide to disinfect a cut, then you know that it is very different from water! Both carbon dioxide (CO2 ) and carbon monoxide (CO) consist of carbon and oxygen, but in different ratios. How do their properties differ? There are different types of compounds. They differ in the nature of the bonds that hold their atoms together. The type of bonds in a compound determines many of its properties. Three types of bonds are ionic, covalent, and metallic bonds. You will read about these three types in later lessons. You can also learn more about them by watching this video: (7:18). MEDIA Click image to the left or use the URL below. URL: Chocolate: Its been revered for millennia by cultures throughout the world. But while its easy to appreciate all of its delicious forms, creating this confection is a complex culinary feat. Local chocolate makers explain the elaborate engineering and chemistry behind this tasty treat. And learn why its actually good for your health! For more information on the science of chocolate, see http://science.kqed.org/quest/video/the-sweet-science-of-chocolate/ . MEDIA Click image to the left or use the URL below. URL:
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Elements form compounds when they combine chemically. Their atoms join together to form molecules, crystals, or other structures. The atoms are held together by chemical bonds. A chemical bond is a force of attraction between atoms or ions. It occurs when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom. You can learn more about chemical bonds in this video: MEDIA Click image to the left or use the URL below. URL: Look at the example of water in Figure 7.1. A water molecule consists of two atoms of hydrogen and one atom of oxygen. Each hydrogen atom has just one electron. The oxygen atom has six valence electrons. In a water molecule, two hydrogen atoms share their two electrons with the six valence electrons of one oxygen atom. By sharing electrons, each atom has electrons available to fill its sole or outer energy level. This gives it a more stable arrangement of electrons that takes less energy to maintain. Water (H2 O) is an example of a chemical compound. Water molecules always consist of two atoms of hydrogen and one atom of oxygen. Like water, all other chemical compounds consist of a fixed ratio of elements. It doesnt matter how much or how little of a compound there is. It always has the same composition. Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table 7.1 shows some other examples of compounds and their chemical formulas. Name of Compound Electron Dot Diagram Numbers of Atoms Chemical Formula Name of Compound Hydrogen chloride Electron Dot Diagram Numbers of Atoms H=1 Cl = 1 Chemical Formula HCl Methane C=1 H=4 CH4 Hydrogen peroxide H=2 O=2 H2 O2 Carbon dioxide C=1 O=2 CO2 Problem Solving Problem: A molecule of ammonia consists of one atom of nitrogen (N) and three atoms of hydrogen (H). What is its chemical formula? Solution: The chemical formula is NH3 . You Try It! Problem: A molecule of nitrogen dioxide consists of one atom of nitrogen (N) and two atoms of oxygen (O). What is its chemical formula? The same elements may combine in different ratios. If they do, they form different compounds. Figure 7.2 shows some examples. Both water (H2 O) and hydrogen peroxide (H2 O2 ) consist of hydrogen and oxygen. However, they have different ratios of the two elements. As a result, water and hydrogen peroxide are different compounds with different properties. If youve ever used hydrogen peroxide to disinfect a cut, then you know that it is very different from water! Both carbon dioxide (CO2 ) and carbon monoxide (CO) consist of carbon and oxygen, but in different ratios. How do their properties differ? There are different types of compounds. They differ in the nature of the bonds that hold their atoms together. The type of bonds in a compound determines many of its properties. Three types of bonds are ionic, covalent, and metallic bonds. You will read about these three types in later lessons. You can also learn more about them by watching this video: (7:18). MEDIA Click image to the left or use the URL below. URL: Chocolate: Its been revered for millennia by cultures throughout the world. But while its easy to appreciate all of its delicious forms, creating this confection is a complex culinary feat. Local chocolate makers explain the elaborate engineering and chemistry behind this tasty treat. And learn why its actually good for your health! For more information on the science of chocolate, see http://science.kqed.org/quest/video/the-sweet-science-of-chocolate/ . MEDIA Click image to the left or use the URL below. URL:
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Elements form compounds when they combine chemically. Their atoms join together to form molecules, crystals, or other structures. The atoms are held together by chemical bonds. A chemical bond is a force of attraction between atoms or ions. It occurs when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom. You can learn more about chemical bonds in this video: MEDIA Click image to the left or use the URL below. URL: Look at the example of water in Figure 7.1. A water molecule consists of two atoms of hydrogen and one atom of oxygen. Each hydrogen atom has just one electron. The oxygen atom has six valence electrons. In a water molecule, two hydrogen atoms share their two electrons with the six valence electrons of one oxygen atom. By sharing electrons, each atom has electrons available to fill its sole or outer energy level. This gives it a more stable arrangement of electrons that takes less energy to maintain. Water (H2 O) is an example of a chemical compound. Water molecules always consist of two atoms of hydrogen and one atom of oxygen. Like water, all other chemical compounds consist of a fixed ratio of elements. It doesnt matter how much or how little of a compound there is. It always has the same composition. Elements are represented by chemical symbols. Examples are H for hydrogen and O for oxygen. Compounds are represented by chemical formulas. Youve already seen the chemical formula for water. Its H2 O. The subscript 2 after the H shows that there are two atoms of hydrogen in a molecule of water. The O for oxygen has no subscript. When there is just one atom of an element in a molecule, no subscript is used. Table 7.1 shows some other examples of compounds and their chemical formulas. Name of Compound Electron Dot Diagram Numbers of Atoms Chemical Formula Name of Compound Hydrogen chloride Electron Dot Diagram Numbers of Atoms H=1 Cl = 1 Chemical Formula HCl Methane C=1 H=4 CH4 Hydrogen peroxide H=2 O=2 H2 O2 Carbon dioxide C=1 O=2 CO2 Problem Solving Problem: A molecule of ammonia consists of one atom of nitrogen (N) and three atoms of hydrogen (H). What is its chemical formula? Solution: The chemical formula is NH3 . You Try It! Problem: A molecule of nitrogen dioxide consists of one atom of nitrogen (N) and two atoms of oxygen (O). What is its chemical formula? The same elements may combine in different ratios. If they do, they form different compounds. Figure 7.2 shows some examples. Both water (H2 O) and hydrogen peroxide (H2 O2 ) consist of hydrogen and oxygen. However, they have different ratios of the two elements. As a result, water and hydrogen peroxide are different compounds with different properties. If youve ever used hydrogen peroxide to disinfect a cut, then you know that it is very different from water! Both carbon dioxide (CO2 ) and carbon monoxide (CO) consist of carbon and oxygen, but in different ratios. How do their properties differ? There are different types of compounds. They differ in the nature of the bonds that hold their atoms together. The type of bonds in a compound determines many of its properties. Three types of bonds are ionic, covalent, and metallic bonds. You will read about these three types in later lessons. You can also learn more about them by watching this video: (7:18). MEDIA Click image to the left or use the URL below. URL: Chocolate: Its been revered for millennia by cultures throughout the world. But while its easy to appreciate all of its delicious forms, creating this confection is a complex culinary feat. Local chocolate makers explain the elaborate engineering and chemistry behind this tasty treat. And learn why its actually good for your health! For more information on the science of chocolate, see http://science.kqed.org/quest/video/the-sweet-science-of-chocolate/ . MEDIA Click image to the left or use the URL below. URL:
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Weathering is the process that changes solid rock into sediments. Sediments were described in the chapter "Ma- terials of Earths Crust." With weathering, rock is disintegrated. It breaks into pieces. Once these sediments are separated from the rocks, erosion is the process that moves the sediments. While plate tectonics forces work to build huge mountains and other landscapes, the forces of weathering gradually wear those rocks and landscapes away. Together with erosion, tall mountains turn into hills and even plains. The Appalachian Mountains along the east coast of North America were once as tall as the Himalayas. No human being can watch for millions of years as mountains are built, nor can anyone watch as those same mountains gradually are worn away. But imagine a new sidewalk or road. The new road is smooth and even. Over hundreds of years, it will completely disappear, but what happens over one year? What changes would you see? (Figure 1.1). What forces of weathering wear down that road, or rocks or mountains over time? A once smooth road surface has cracks and fractures, plus a large pothole. Click image to the left or use the URL below. URL:
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Weathering is the process that changes solid rock into sediments. Sediments were described in the chapter "Ma- terials of Earths Crust." With weathering, rock is disintegrated. It breaks into pieces. Once these sediments are separated from the rocks, erosion is the process that moves the sediments. While plate tectonics forces work to build huge mountains and other landscapes, the forces of weathering gradually wear those rocks and landscapes away. Together with erosion, tall mountains turn into hills and even plains. The Appalachian Mountains along the east coast of North America were once as tall as the Himalayas. No human being can watch for millions of years as mountains are built, nor can anyone watch as those same mountains gradually are worn away. But imagine a new sidewalk or road. The new road is smooth and even. Over hundreds of years, it will completely disappear, but what happens over one year? What changes would you see? (Figure 1.1). What forces of weathering wear down that road, or rocks or mountains over time? A once smooth road surface has cracks and fractures, plus a large pothole. Click image to the left or use the URL below. URL:
|
the process that moves sediments.
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Weathering is the process that changes solid rock into sediments. Sediments were described in the chapter "Ma- terials of Earths Crust." With weathering, rock is disintegrated. It breaks into pieces. Once these sediments are separated from the rocks, erosion is the process that moves the sediments. While plate tectonics forces work to build huge mountains and other landscapes, the forces of weathering gradually wear those rocks and landscapes away. Together with erosion, tall mountains turn into hills and even plains. The Appalachian Mountains along the east coast of North America were once as tall as the Himalayas. No human being can watch for millions of years as mountains are built, nor can anyone watch as those same mountains gradually are worn away. But imagine a new sidewalk or road. The new road is smooth and even. Over hundreds of years, it will completely disappear, but what happens over one year? What changes would you see? (Figure 1.1). What forces of weathering wear down that road, or rocks or mountains over time? A once smooth road surface has cracks and fractures, plus a large pothole. Click image to the left or use the URL below. URL:
|
if a river in flood picks up a house and moves it downstream, this is
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Bacteria, being single-celled prokaryotic organisms, do not have a male or female version. Bacteria reproduce asexually. In asexual reproduction, the "parent" produces a genetically identical copy of itself. Bacteria reproduce through a process called binary fission. During binary fission, the chromosome copies itself, forming two genetically identical copies. Then, the cell enlarges and divides into two new daughter cells. The two daughter cells are identical to the parent cell. Binary fission can happen very rapidly. Some species of bacteria can double their population in less than ten minutes! This process makes it possible for a tremendous bacterial colony to start from a single cell. Are there male and female bacteria? Of course the answer is no. So, sexual reproduction does not occur in bacteria. But not all new bacteria are clones. This is because bacteria can acquire new DNA. This process occurs in three different ways: 1. Conjugation: In conjugation, DNA passes through an extension on the surface of one bacterium and travels to another bacterium ( Figure 1.1). Bacteria essential exchange DNA via conjugation. 2. Transformation: In transformation, bacteria pick up pieces of DNA from their environment. 3. Transduction: In transduction, viruses that infect bacteria carry DNA from one bacterium to another.
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what is the process in which dna is transferred from one bacterium to another?
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Bacteria, being single-celled prokaryotic organisms, do not have a male or female version. Bacteria reproduce asexually. In asexual reproduction, the "parent" produces a genetically identical copy of itself. Bacteria reproduce through a process called binary fission. During binary fission, the chromosome copies itself, forming two genetically identical copies. Then, the cell enlarges and divides into two new daughter cells. The two daughter cells are identical to the parent cell. Binary fission can happen very rapidly. Some species of bacteria can double their population in less than ten minutes! This process makes it possible for a tremendous bacterial colony to start from a single cell. Are there male and female bacteria? Of course the answer is no. So, sexual reproduction does not occur in bacteria. But not all new bacteria are clones. This is because bacteria can acquire new DNA. This process occurs in three different ways: 1. Conjugation: In conjugation, DNA passes through an extension on the surface of one bacterium and travels to another bacterium ( Figure 1.1). Bacteria essential exchange DNA via conjugation. 2. Transformation: In transformation, bacteria pick up pieces of DNA from their environment. 3. Transduction: In transduction, viruses that infect bacteria carry DNA from one bacterium to another.
|
what is the process in which a virus carries dna from one bacteria to another?
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Bacteria, being single-celled prokaryotic organisms, do not have a male or female version. Bacteria reproduce asexually. In asexual reproduction, the "parent" produces a genetically identical copy of itself. Bacteria reproduce through a process called binary fission. During binary fission, the chromosome copies itself, forming two genetically identical copies. Then, the cell enlarges and divides into two new daughter cells. The two daughter cells are identical to the parent cell. Binary fission can happen very rapidly. Some species of bacteria can double their population in less than ten minutes! This process makes it possible for a tremendous bacterial colony to start from a single cell. Are there male and female bacteria? Of course the answer is no. So, sexual reproduction does not occur in bacteria. But not all new bacteria are clones. This is because bacteria can acquire new DNA. This process occurs in three different ways: 1. Conjugation: In conjugation, DNA passes through an extension on the surface of one bacterium and travels to another bacterium ( Figure 1.1). Bacteria essential exchange DNA via conjugation. 2. Transformation: In transformation, bacteria pick up pieces of DNA from their environment. 3. Transduction: In transduction, viruses that infect bacteria carry DNA from one bacterium to another.
|
sexual reproduction in bacteria occurs through what mechanism?
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When you take a walk along a beach, what do you find there? Sand, the ocean, lots of sunlight. You may also find shells. The shells you find are most likely left by organisms in the phylum Mollusca. On the beach, you can find the shells of many different mollusks ( Figure 1.1), including clams, mussels, scallops, oysters, and snails. Mollusks are invertebrates that usually have a hard shell, a mantle, and a radula. Their glossy pearls, mother of pearl, and abalone shells are like pieces of jewelry. Some mollusks, such as squid and octopus, do not have shells. The Mollusks body is often divided into different parts ( Figure 1.2): On the beach, you can find a wide variety of mollusk shells. 1. A head with eyes or tentacles. 2. In most species, a muscular foot, which helps the mollusk move. Some mollusks use the foot for burrowing into the sand, and others use it for jet-propulsion. 3. A mantle, or fold of the outer skin lining the shell. The mantle often releases calcium carbonate, which creates an external shell, just like the ones you find on the beach. The shell is made of chitin, a tough, semitransparent substance. 4. A mass housing the organs. 5. A complete digestive tract that begins at the mouth and runs to the anus. 6. Most ocean mollusks have a gill or gills to absorb oxygen from the water. 7. Many species have a feeding structure, the radula, found only in mollusks. The radula can be thought of as a "tongue-like" structure. The radula is made mostly of chitin. Types of radulae range from structures used to scrape algae off of rocks to the beaks of squid and octopuses. This is the basic body plan of a mollusk. Note the mantle, gills, and radula. Keep in mind the basic body plan can differ slightly among the mollusks. Mollusks are probably most closely related to organisms in the phylum Annelida, also known as segmented worms. This phylum includes the earthworm and leech. Scientists believe these two groups are related because, when they are in the early stage of development, they look very similar. Mollusks also share features of their organ systems with segmented worms. Unlike segmented worms, however, mollusks do not have body segmentation. The basic mollusk body shape is usually quite different as well.
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When you take a walk along a beach, what do you find there? Sand, the ocean, lots of sunlight. You may also find shells. The shells you find are most likely left by organisms in the phylum Mollusca. On the beach, you can find the shells of many different mollusks ( Figure 1.1), including clams, mussels, scallops, oysters, and snails. Mollusks are invertebrates that usually have a hard shell, a mantle, and a radula. Their glossy pearls, mother of pearl, and abalone shells are like pieces of jewelry. Some mollusks, such as squid and octopus, do not have shells. The Mollusks body is often divided into different parts ( Figure 1.2): On the beach, you can find a wide variety of mollusk shells. 1. A head with eyes or tentacles. 2. In most species, a muscular foot, which helps the mollusk move. Some mollusks use the foot for burrowing into the sand, and others use it for jet-propulsion. 3. A mantle, or fold of the outer skin lining the shell. The mantle often releases calcium carbonate, which creates an external shell, just like the ones you find on the beach. The shell is made of chitin, a tough, semitransparent substance. 4. A mass housing the organs. 5. A complete digestive tract that begins at the mouth and runs to the anus. 6. Most ocean mollusks have a gill or gills to absorb oxygen from the water. 7. Many species have a feeding structure, the radula, found only in mollusks. The radula can be thought of as a "tongue-like" structure. The radula is made mostly of chitin. Types of radulae range from structures used to scrape algae off of rocks to the beaks of squid and octopuses. This is the basic body plan of a mollusk. Note the mantle, gills, and radula. Keep in mind the basic body plan can differ slightly among the mollusks. Mollusks are probably most closely related to organisms in the phylum Annelida, also known as segmented worms. This phylum includes the earthworm and leech. Scientists believe these two groups are related because, when they are in the early stage of development, they look very similar. Mollusks also share features of their organ systems with segmented worms. Unlike segmented worms, however, mollusks do not have body segmentation. The basic mollusk body shape is usually quite different as well.
|
the foot of a squid is probably used for
|
[
"jet-propulsion."
] |
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When you take a walk along a beach, what do you find there? Sand, the ocean, lots of sunlight. You may also find shells. The shells you find are most likely left by organisms in the phylum Mollusca. On the beach, you can find the shells of many different mollusks ( Figure 1.1), including clams, mussels, scallops, oysters, and snails. Mollusks are invertebrates that usually have a hard shell, a mantle, and a radula. Their glossy pearls, mother of pearl, and abalone shells are like pieces of jewelry. Some mollusks, such as squid and octopus, do not have shells. The Mollusks body is often divided into different parts ( Figure 1.2): On the beach, you can find a wide variety of mollusk shells. 1. A head with eyes or tentacles. 2. In most species, a muscular foot, which helps the mollusk move. Some mollusks use the foot for burrowing into the sand, and others use it for jet-propulsion. 3. A mantle, or fold of the outer skin lining the shell. The mantle often releases calcium carbonate, which creates an external shell, just like the ones you find on the beach. The shell is made of chitin, a tough, semitransparent substance. 4. A mass housing the organs. 5. A complete digestive tract that begins at the mouth and runs to the anus. 6. Most ocean mollusks have a gill or gills to absorb oxygen from the water. 7. Many species have a feeding structure, the radula, found only in mollusks. The radula can be thought of as a "tongue-like" structure. The radula is made mostly of chitin. Types of radulae range from structures used to scrape algae off of rocks to the beaks of squid and octopuses. This is the basic body plan of a mollusk. Note the mantle, gills, and radula. Keep in mind the basic body plan can differ slightly among the mollusks. Mollusks are probably most closely related to organisms in the phylum Annelida, also known as segmented worms. This phylum includes the earthworm and leech. Scientists believe these two groups are related because, when they are in the early stage of development, they look very similar. Mollusks also share features of their organ systems with segmented worms. Unlike segmented worms, however, mollusks do not have body segmentation. The basic mollusk body shape is usually quite different as well.
|
what type of worms are most closely related to mollusks?
|
[
"segmented worms"
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With transform plate boundaries, the two slabs of lithosphere are sliding past each other in opposite directions. The boundary between the two plates is a transform fault. Transform faults on continents separate two massive plates of lithosphere. As they slide past each other, they may have massive earthquakes. The San Andreas Fault in California is perhaps the worlds most famous transform fault. Land on the west side is moving northward relative to land on the east side. This means that Los Angeles is moving northward relative to Palm Springs. The San Andreas Fault is famous because it is the site of many earthquakes, large and small. (Figure At the San Andreas Fault in California, the Pacific Plate is sliding northeast relative to the North American plate, which is moving southwest. At the northern end of the picture, the transform boundary turns into a subduction zone. Transform plate boundaries are also found in the oceans. They divide mid-ocean ridges into segments. In the diagram of western North America, the mid-ocean ridge up at the top, labeled the Juan de Fuca Ridge, is broken apart by a transform fault in the oceans. A careful look will show that different plates are found on each side of the ridge: the Juan de Fuca plate on the east side and the Pacific Plate on the west side.
|
what type of boundary is found at the san andreas fault?
|
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"transform"
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With transform plate boundaries, the two slabs of lithosphere are sliding past each other in opposite directions. The boundary between the two plates is a transform fault. Transform faults on continents separate two massive plates of lithosphere. As they slide past each other, they may have massive earthquakes. The San Andreas Fault in California is perhaps the worlds most famous transform fault. Land on the west side is moving northward relative to land on the east side. This means that Los Angeles is moving northward relative to Palm Springs. The San Andreas Fault is famous because it is the site of many earthquakes, large and small. (Figure At the San Andreas Fault in California, the Pacific Plate is sliding northeast relative to the North American plate, which is moving southwest. At the northern end of the picture, the transform boundary turns into a subduction zone. Transform plate boundaries are also found in the oceans. They divide mid-ocean ridges into segments. In the diagram of western North America, the mid-ocean ridge up at the top, labeled the Juan de Fuca Ridge, is broken apart by a transform fault in the oceans. A careful look will show that different plates are found on each side of the ridge: the Juan de Fuca plate on the east side and the Pacific Plate on the west side.
|
when two slabs of lithosphere slide past each other, the result is
|
[
"earthquakes"
] |
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With transform plate boundaries, the two slabs of lithosphere are sliding past each other in opposite directions. The boundary between the two plates is a transform fault. Transform faults on continents separate two massive plates of lithosphere. As they slide past each other, they may have massive earthquakes. The San Andreas Fault in California is perhaps the worlds most famous transform fault. Land on the west side is moving northward relative to land on the east side. This means that Los Angeles is moving northward relative to Palm Springs. The San Andreas Fault is famous because it is the site of many earthquakes, large and small. (Figure At the San Andreas Fault in California, the Pacific Plate is sliding northeast relative to the North American plate, which is moving southwest. At the northern end of the picture, the transform boundary turns into a subduction zone. Transform plate boundaries are also found in the oceans. They divide mid-ocean ridges into segments. In the diagram of western North America, the mid-ocean ridge up at the top, labeled the Juan de Fuca Ridge, is broken apart by a transform fault in the oceans. A careful look will show that different plates are found on each side of the ridge: the Juan de Fuca plate on the east side and the Pacific Plate on the west side.
|
over millions of years, which direction would you find los angeles in relation to where it is now?
|
[
"north"
] |
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Rocks deforming plastically under compressive stresses crumple into folds. They do not return to their original shape. If the rocks experience more stress, they may undergo more folding or even fracture. You can see three types of folds. A monocline is a simple bend in the rock layers so that they are no longer horizontal (see Figure 1.1 for an example). At Utahs Cockscomb, the rocks plunge downward in a monocline. What you see in the image appears to be a monocline. Are you certain it is a monocline? What else might it be? What would you have to do to figure it out? Anticline: An anticline is a fold that arches upward. The rocks dip away from the center of the fold (Figure 1.2). The oldest rocks are at the center of an anticline and the youngest are draped over them. When rocks arch upward to form a circular structure, that structure is called a dome. If the top of the dome is sliced off, where are the oldest rocks located? A syncline is a fold that bends downward. The youngest rocks are at the center and the oldest are at the outside (Figure 1.3). When rocks bend downward in a circular structure, that structure is called a basin (Figure 1.4). If the rocks are exposed at the surface, where are the oldest rocks located? Click image to the left or use the URL below. URL: Anticlines are formations that have folded rocks upward. (a) Schematic of a syncline. (b) This syncline is in Rainbow Basin, California. Some folding can be fairly complicated. What do you see in the photo above?
|
rocks that deform plastically under compressive stresses crumple into this.
|
[
"folds"
] |
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Rocks deforming plastically under compressive stresses crumple into folds. They do not return to their original shape. If the rocks experience more stress, they may undergo more folding or even fracture. You can see three types of folds. A monocline is a simple bend in the rock layers so that they are no longer horizontal (see Figure 1.1 for an example). At Utahs Cockscomb, the rocks plunge downward in a monocline. What you see in the image appears to be a monocline. Are you certain it is a monocline? What else might it be? What would you have to do to figure it out? Anticline: An anticline is a fold that arches upward. The rocks dip away from the center of the fold (Figure 1.2). The oldest rocks are at the center of an anticline and the youngest are draped over them. When rocks arch upward to form a circular structure, that structure is called a dome. If the top of the dome is sliced off, where are the oldest rocks located? A syncline is a fold that bends downward. The youngest rocks are at the center and the oldest are at the outside (Figure 1.3). When rocks bend downward in a circular structure, that structure is called a basin (Figure 1.4). If the rocks are exposed at the surface, where are the oldest rocks located? Click image to the left or use the URL below. URL: Anticlines are formations that have folded rocks upward. (a) Schematic of a syncline. (b) This syncline is in Rainbow Basin, California. Some folding can be fairly complicated. What do you see in the photo above?
|
an anticline has rocks that bend.
|
[
"upward"
] |
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Rocks deforming plastically under compressive stresses crumple into folds. They do not return to their original shape. If the rocks experience more stress, they may undergo more folding or even fracture. You can see three types of folds. A monocline is a simple bend in the rock layers so that they are no longer horizontal (see Figure 1.1 for an example). At Utahs Cockscomb, the rocks plunge downward in a monocline. What you see in the image appears to be a monocline. Are you certain it is a monocline? What else might it be? What would you have to do to figure it out? Anticline: An anticline is a fold that arches upward. The rocks dip away from the center of the fold (Figure 1.2). The oldest rocks are at the center of an anticline and the youngest are draped over them. When rocks arch upward to form a circular structure, that structure is called a dome. If the top of the dome is sliced off, where are the oldest rocks located? A syncline is a fold that bends downward. The youngest rocks are at the center and the oldest are at the outside (Figure 1.3). When rocks bend downward in a circular structure, that structure is called a basin (Figure 1.4). If the rocks are exposed at the surface, where are the oldest rocks located? Click image to the left or use the URL below. URL: Anticlines are formations that have folded rocks upward. (a) Schematic of a syncline. (b) This syncline is in Rainbow Basin, California. Some folding can be fairly complicated. What do you see in the photo above?
|
the michigan basin is made by rock bending
|
[
"downward"
] |
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A mechanical wave is a disturbance in matter that transfers energy from place to place. A mechanical wave starts when matter is disturbed. An example of a mechanical wave is pictured in Figure 19.1. A drop of water falls into a pond. This disturbs the water in the pond. What happens next? The disturbance travels outward from the drop in all directions. This is the wave. A source of energy is needed to start a mechanical wave. In this case, the energy comes from the falling drop of water. The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the medium dont actually travel along with the wave. Only the energy travels. The particles of the medium just vibrate, or move back-and- forth or up-and-down in one spot, always returning to their original positions. As the particles vibrate, they pass the energy of the disturbance to the particles next to them, which pass the energy to the particles next to them, and so on. There are three types of mechanical waves. They differ in how they travel through a medium. The three types are transverse, longitudinal, and surface waves. All three types are described in detail below. A transverse wave is a wave in which the medium vibrates at right angles to the direction that the wave travels. An example of a transverse wave is a wave in a rope, like the one pictured in Figure 19.2. In this wave, energy is provided by a persons hand moving one end of the rope up and down. The direction of the wave is down the length of the rope away from the persons hand. The rope itself moves up and down as the wave passes through it. You can see a brief video of a transverse wave in a rope at this URL: . To see a transverse wave in slow motion, go to this URL: (0:22). MEDIA Click image to the left or use the URL below. URL: A transverse wave can be characterized by the high and low points reached by particles of the medium as the wave passes through. This is illustrated in Figure 19.3. The high points are called crests, and the low points are called troughs. Another example of transverse waves occurs with earthquakes. The disturbance that causes an earthquake sends transverse waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called secondary, or S, waves. An S wave is illustrated in Figure 19.4. A longitudinal wave is a wave in which the medium vibrates in the same direction that the wave travels. An example of a longitudinal wave is a wave in a spring, like the one in Figure 19.5. In this wave, the energy is provided by a persons hand pushing and pulling the spring. The coils of the spring first crowd closer together and then spread farther apart as the disturbance passes through them. The direction of the wave is down the length of the spring, or the same direction in which the coils move. You can see a video of a longitudinal wave in a spring at this URL: http A longitudinal wave can be characterized by the compressions and rarefactions of the medium. This is illustrated in Figure 19.6. Compressions are the places where the coils are crowded together, and rarefactions are the places where the coils are spread apart. Earthquakes cause longitudinal waves as well as transverse waves. The disturbance that causes an earthquake sends longitudinal waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called primary, or P, waves. They are illustrated in Figure 19.7. A surface wave is a wave that travels along the surface of a medium. It combines a transverse wave and a longitudinal wave. Ocean waves are surface waves. They travel on the surface of the water between the ocean
|
The parts of a longitudinal wave where particles of matter are spread farthest apart are called
|
[
"rarefactions."
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A mechanical wave is a disturbance in matter that transfers energy from place to place. A mechanical wave starts when matter is disturbed. An example of a mechanical wave is pictured in Figure 19.1. A drop of water falls into a pond. This disturbs the water in the pond. What happens next? The disturbance travels outward from the drop in all directions. This is the wave. A source of energy is needed to start a mechanical wave. In this case, the energy comes from the falling drop of water. The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the medium dont actually travel along with the wave. Only the energy travels. The particles of the medium just vibrate, or move back-and- forth or up-and-down in one spot, always returning to their original positions. As the particles vibrate, they pass the energy of the disturbance to the particles next to them, which pass the energy to the particles next to them, and so on. There are three types of mechanical waves. They differ in how they travel through a medium. The three types are transverse, longitudinal, and surface waves. All three types are described in detail below. A transverse wave is a wave in which the medium vibrates at right angles to the direction that the wave travels. An example of a transverse wave is a wave in a rope, like the one pictured in Figure 19.2. In this wave, energy is provided by a persons hand moving one end of the rope up and down. The direction of the wave is down the length of the rope away from the persons hand. The rope itself moves up and down as the wave passes through it. You can see a brief video of a transverse wave in a rope at this URL: . To see a transverse wave in slow motion, go to this URL: (0:22). MEDIA Click image to the left or use the URL below. URL: A transverse wave can be characterized by the high and low points reached by particles of the medium as the wave passes through. This is illustrated in Figure 19.3. The high points are called crests, and the low points are called troughs. Another example of transverse waves occurs with earthquakes. The disturbance that causes an earthquake sends transverse waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called secondary, or S, waves. An S wave is illustrated in Figure 19.4. A longitudinal wave is a wave in which the medium vibrates in the same direction that the wave travels. An example of a longitudinal wave is a wave in a spring, like the one in Figure 19.5. In this wave, the energy is provided by a persons hand pushing and pulling the spring. The coils of the spring first crowd closer together and then spread farther apart as the disturbance passes through them. The direction of the wave is down the length of the spring, or the same direction in which the coils move. You can see a video of a longitudinal wave in a spring at this URL: http A longitudinal wave can be characterized by the compressions and rarefactions of the medium. This is illustrated in Figure 19.6. Compressions are the places where the coils are crowded together, and rarefactions are the places where the coils are spread apart. Earthquakes cause longitudinal waves as well as transverse waves. The disturbance that causes an earthquake sends longitudinal waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called primary, or P, waves. They are illustrated in Figure 19.7. A surface wave is a wave that travels along the surface of a medium. It combines a transverse wave and a longitudinal wave. Ocean waves are surface waves. They travel on the surface of the water between the ocean
|
The lowest parts of a transverse wave is are known as
|
[
"troughs."
] |
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A mechanical wave is a disturbance in matter that transfers energy from place to place. A mechanical wave starts when matter is disturbed. An example of a mechanical wave is pictured in Figure 19.1. A drop of water falls into a pond. This disturbs the water in the pond. What happens next? The disturbance travels outward from the drop in all directions. This is the wave. A source of energy is needed to start a mechanical wave. In this case, the energy comes from the falling drop of water. The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the medium dont actually travel along with the wave. Only the energy travels. The particles of the medium just vibrate, or move back-and- forth or up-and-down in one spot, always returning to their original positions. As the particles vibrate, they pass the energy of the disturbance to the particles next to them, which pass the energy to the particles next to them, and so on. There are three types of mechanical waves. They differ in how they travel through a medium. The three types are transverse, longitudinal, and surface waves. All three types are described in detail below. A transverse wave is a wave in which the medium vibrates at right angles to the direction that the wave travels. An example of a transverse wave is a wave in a rope, like the one pictured in Figure 19.2. In this wave, energy is provided by a persons hand moving one end of the rope up and down. The direction of the wave is down the length of the rope away from the persons hand. The rope itself moves up and down as the wave passes through it. You can see a brief video of a transverse wave in a rope at this URL: . To see a transverse wave in slow motion, go to this URL: (0:22). MEDIA Click image to the left or use the URL below. URL: A transverse wave can be characterized by the high and low points reached by particles of the medium as the wave passes through. This is illustrated in Figure 19.3. The high points are called crests, and the low points are called troughs. Another example of transverse waves occurs with earthquakes. The disturbance that causes an earthquake sends transverse waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called secondary, or S, waves. An S wave is illustrated in Figure 19.4. A longitudinal wave is a wave in which the medium vibrates in the same direction that the wave travels. An example of a longitudinal wave is a wave in a spring, like the one in Figure 19.5. In this wave, the energy is provided by a persons hand pushing and pulling the spring. The coils of the spring first crowd closer together and then spread farther apart as the disturbance passes through them. The direction of the wave is down the length of the spring, or the same direction in which the coils move. You can see a video of a longitudinal wave in a spring at this URL: http A longitudinal wave can be characterized by the compressions and rarefactions of the medium. This is illustrated in Figure 19.6. Compressions are the places where the coils are crowded together, and rarefactions are the places where the coils are spread apart. Earthquakes cause longitudinal waves as well as transverse waves. The disturbance that causes an earthquake sends longitudinal waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called primary, or P, waves. They are illustrated in Figure 19.7. A surface wave is a wave that travels along the surface of a medium. It combines a transverse wave and a longitudinal wave. Ocean waves are surface waves. They travel on the surface of the water between the ocean
|
disturbance in matter that transfers energy from place to place
|
[
"mechanical wave"
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A mechanical wave is a disturbance in matter that transfers energy from place to place. A mechanical wave starts when matter is disturbed. An example of a mechanical wave is pictured in Figure 19.1. A drop of water falls into a pond. This disturbs the water in the pond. What happens next? The disturbance travels outward from the drop in all directions. This is the wave. A source of energy is needed to start a mechanical wave. In this case, the energy comes from the falling drop of water. The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the medium dont actually travel along with the wave. Only the energy travels. The particles of the medium just vibrate, or move back-and- forth or up-and-down in one spot, always returning to their original positions. As the particles vibrate, they pass the energy of the disturbance to the particles next to them, which pass the energy to the particles next to them, and so on. There are three types of mechanical waves. They differ in how they travel through a medium. The three types are transverse, longitudinal, and surface waves. All three types are described in detail below. A transverse wave is a wave in which the medium vibrates at right angles to the direction that the wave travels. An example of a transverse wave is a wave in a rope, like the one pictured in Figure 19.2. In this wave, energy is provided by a persons hand moving one end of the rope up and down. The direction of the wave is down the length of the rope away from the persons hand. The rope itself moves up and down as the wave passes through it. You can see a brief video of a transverse wave in a rope at this URL: . To see a transverse wave in slow motion, go to this URL: (0:22). MEDIA Click image to the left or use the URL below. URL: A transverse wave can be characterized by the high and low points reached by particles of the medium as the wave passes through. This is illustrated in Figure 19.3. The high points are called crests, and the low points are called troughs. Another example of transverse waves occurs with earthquakes. The disturbance that causes an earthquake sends transverse waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called secondary, or S, waves. An S wave is illustrated in Figure 19.4. A longitudinal wave is a wave in which the medium vibrates in the same direction that the wave travels. An example of a longitudinal wave is a wave in a spring, like the one in Figure 19.5. In this wave, the energy is provided by a persons hand pushing and pulling the spring. The coils of the spring first crowd closer together and then spread farther apart as the disturbance passes through them. The direction of the wave is down the length of the spring, or the same direction in which the coils move. You can see a video of a longitudinal wave in a spring at this URL: http A longitudinal wave can be characterized by the compressions and rarefactions of the medium. This is illustrated in Figure 19.6. Compressions are the places where the coils are crowded together, and rarefactions are the places where the coils are spread apart. Earthquakes cause longitudinal waves as well as transverse waves. The disturbance that causes an earthquake sends longitudinal waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called primary, or P, waves. They are illustrated in Figure 19.7. A surface wave is a wave that travels along the surface of a medium. It combines a transverse wave and a longitudinal wave. Ocean waves are surface waves. They travel on the surface of the water between the ocean
|
wave in which particles of the medium vibrate at right angles to the direction that the wave travels
|
[
"transverse wave"
] |
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A mechanical wave is a disturbance in matter that transfers energy from place to place. A mechanical wave starts when matter is disturbed. An example of a mechanical wave is pictured in Figure 19.1. A drop of water falls into a pond. This disturbs the water in the pond. What happens next? The disturbance travels outward from the drop in all directions. This is the wave. A source of energy is needed to start a mechanical wave. In this case, the energy comes from the falling drop of water. The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the medium dont actually travel along with the wave. Only the energy travels. The particles of the medium just vibrate, or move back-and- forth or up-and-down in one spot, always returning to their original positions. As the particles vibrate, they pass the energy of the disturbance to the particles next to them, which pass the energy to the particles next to them, and so on. There are three types of mechanical waves. They differ in how they travel through a medium. The three types are transverse, longitudinal, and surface waves. All three types are described in detail below. A transverse wave is a wave in which the medium vibrates at right angles to the direction that the wave travels. An example of a transverse wave is a wave in a rope, like the one pictured in Figure 19.2. In this wave, energy is provided by a persons hand moving one end of the rope up and down. The direction of the wave is down the length of the rope away from the persons hand. The rope itself moves up and down as the wave passes through it. You can see a brief video of a transverse wave in a rope at this URL: . To see a transverse wave in slow motion, go to this URL: (0:22). MEDIA Click image to the left or use the URL below. URL: A transverse wave can be characterized by the high and low points reached by particles of the medium as the wave passes through. This is illustrated in Figure 19.3. The high points are called crests, and the low points are called troughs. Another example of transverse waves occurs with earthquakes. The disturbance that causes an earthquake sends transverse waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called secondary, or S, waves. An S wave is illustrated in Figure 19.4. A longitudinal wave is a wave in which the medium vibrates in the same direction that the wave travels. An example of a longitudinal wave is a wave in a spring, like the one in Figure 19.5. In this wave, the energy is provided by a persons hand pushing and pulling the spring. The coils of the spring first crowd closer together and then spread farther apart as the disturbance passes through them. The direction of the wave is down the length of the spring, or the same direction in which the coils move. You can see a video of a longitudinal wave in a spring at this URL: http A longitudinal wave can be characterized by the compressions and rarefactions of the medium. This is illustrated in Figure 19.6. Compressions are the places where the coils are crowded together, and rarefactions are the places where the coils are spread apart. Earthquakes cause longitudinal waves as well as transverse waves. The disturbance that causes an earthquake sends longitudinal waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called primary, or P, waves. They are illustrated in Figure 19.7. A surface wave is a wave that travels along the surface of a medium. It combines a transverse wave and a longitudinal wave. Ocean waves are surface waves. They travel on the surface of the water between the ocean
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A mechanical wave is a disturbance in matter that transfers energy from place to place. A mechanical wave starts when matter is disturbed. An example of a mechanical wave is pictured in Figure 19.1. A drop of water falls into a pond. This disturbs the water in the pond. What happens next? The disturbance travels outward from the drop in all directions. This is the wave. A source of energy is needed to start a mechanical wave. In this case, the energy comes from the falling drop of water. The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the medium dont actually travel along with the wave. Only the energy travels. The particles of the medium just vibrate, or move back-and- forth or up-and-down in one spot, always returning to their original positions. As the particles vibrate, they pass the energy of the disturbance to the particles next to them, which pass the energy to the particles next to them, and so on. There are three types of mechanical waves. They differ in how they travel through a medium. The three types are transverse, longitudinal, and surface waves. All three types are described in detail below. A transverse wave is a wave in which the medium vibrates at right angles to the direction that the wave travels. An example of a transverse wave is a wave in a rope, like the one pictured in Figure 19.2. In this wave, energy is provided by a persons hand moving one end of the rope up and down. The direction of the wave is down the length of the rope away from the persons hand. The rope itself moves up and down as the wave passes through it. You can see a brief video of a transverse wave in a rope at this URL: . To see a transverse wave in slow motion, go to this URL: (0:22). MEDIA Click image to the left or use the URL below. URL: A transverse wave can be characterized by the high and low points reached by particles of the medium as the wave passes through. This is illustrated in Figure 19.3. The high points are called crests, and the low points are called troughs. Another example of transverse waves occurs with earthquakes. The disturbance that causes an earthquake sends transverse waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called secondary, or S, waves. An S wave is illustrated in Figure 19.4. A longitudinal wave is a wave in which the medium vibrates in the same direction that the wave travels. An example of a longitudinal wave is a wave in a spring, like the one in Figure 19.5. In this wave, the energy is provided by a persons hand pushing and pulling the spring. The coils of the spring first crowd closer together and then spread farther apart as the disturbance passes through them. The direction of the wave is down the length of the spring, or the same direction in which the coils move. You can see a video of a longitudinal wave in a spring at this URL: http A longitudinal wave can be characterized by the compressions and rarefactions of the medium. This is illustrated in Figure 19.6. Compressions are the places where the coils are crowded together, and rarefactions are the places where the coils are spread apart. Earthquakes cause longitudinal waves as well as transverse waves. The disturbance that causes an earthquake sends longitudinal waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called primary, or P, waves. They are illustrated in Figure 19.7. A surface wave is a wave that travels along the surface of a medium. It combines a transverse wave and a longitudinal wave. Ocean waves are surface waves. They travel on the surface of the water between the ocean
|
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A mechanical wave is a disturbance in matter that transfers energy from place to place. A mechanical wave starts when matter is disturbed. An example of a mechanical wave is pictured in Figure 19.1. A drop of water falls into a pond. This disturbs the water in the pond. What happens next? The disturbance travels outward from the drop in all directions. This is the wave. A source of energy is needed to start a mechanical wave. In this case, the energy comes from the falling drop of water. The energy of a mechanical wave can travel only through matter. This matter is called the medium (plural, media). The medium in Figure 19.1 is a liquid the water in the pond. But the medium of a mechanical wave can be any state of matter, including a solid or a gas. Its important to note that particles of matter in the medium dont actually travel along with the wave. Only the energy travels. The particles of the medium just vibrate, or move back-and- forth or up-and-down in one spot, always returning to their original positions. As the particles vibrate, they pass the energy of the disturbance to the particles next to them, which pass the energy to the particles next to them, and so on. There are three types of mechanical waves. They differ in how they travel through a medium. The three types are transverse, longitudinal, and surface waves. All three types are described in detail below. A transverse wave is a wave in which the medium vibrates at right angles to the direction that the wave travels. An example of a transverse wave is a wave in a rope, like the one pictured in Figure 19.2. In this wave, energy is provided by a persons hand moving one end of the rope up and down. The direction of the wave is down the length of the rope away from the persons hand. The rope itself moves up and down as the wave passes through it. You can see a brief video of a transverse wave in a rope at this URL: . To see a transverse wave in slow motion, go to this URL: (0:22). MEDIA Click image to the left or use the URL below. URL: A transverse wave can be characterized by the high and low points reached by particles of the medium as the wave passes through. This is illustrated in Figure 19.3. The high points are called crests, and the low points are called troughs. Another example of transverse waves occurs with earthquakes. The disturbance that causes an earthquake sends transverse waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called secondary, or S, waves. An S wave is illustrated in Figure 19.4. A longitudinal wave is a wave in which the medium vibrates in the same direction that the wave travels. An example of a longitudinal wave is a wave in a spring, like the one in Figure 19.5. In this wave, the energy is provided by a persons hand pushing and pulling the spring. The coils of the spring first crowd closer together and then spread farther apart as the disturbance passes through them. The direction of the wave is down the length of the spring, or the same direction in which the coils move. You can see a video of a longitudinal wave in a spring at this URL: http A longitudinal wave can be characterized by the compressions and rarefactions of the medium. This is illustrated in Figure 19.6. Compressions are the places where the coils are crowded together, and rarefactions are the places where the coils are spread apart. Earthquakes cause longitudinal waves as well as transverse waves. The disturbance that causes an earthquake sends longitudinal waves through underground rocks in all directions from the disturbance. Earthquake waves that travel this way are called primary, or P, waves. They are illustrated in Figure 19.7. A surface wave is a wave that travels along the surface of a medium. It combines a transverse wave and a longitudinal wave. Ocean waves are surface waves. They travel on the surface of the water between the ocean
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Mercury is the smallest planet. It has no moon. The planet is also closest to the Sun and appears in Figure 25.7. As Figure 25.8 shows, the surface of Mercury is covered with craters, like Earths Moon. The presence of impact craters that are so old means that Mercury hasnt changed much geologically for billions of years. With only a trace of an atmosphere, it has no weather to wear down the ancient craters. Because Mercury is so close to the Sun, it is difficult to observe from Earth, even with a telescope. The Mariner 10 spacecraft did a flyby of Mercury in 19741975, which was the best data from the planet for decades. In 2004, the MESSENGER mission left Earth. On its way to Mercury it did one flyby of Earth, two of Venus and three of Mercury. In March 2011, MESSENGER became the first spacecraft to enter an orbit around Mercury. During its year-long mission, the craft will map the planets surface and conduct other studies. One of these images can be seen in Figure 25.9. Mercury is named for the Roman messenger god. Mercury was a messenger because he could run extremely fast. The Greeks gave the planet this name because Mercury moves very quickly in its orbit around the Sun. Mercury orbits the Sun in just 88 Earth days. Mercury has a very short year, but it also has very long days. Mercury rotates slowly on its axis, turning exactly three times for every two times it orbits the Sun. Therefore, each day on Mercury is 58 Earth days long. Mercury is very close to the Sun, so it can get very hot. Mercury also has virtually no atmosphere. As the planet rotates very slowly, the temperature varies tremendously. In direct sunlight, the surface can be as hot as 427C (801F). On the dark side, the surface can be as cold as 183C (297F)! The coldest temperatures may be on the insides of craters. Most of Mercury is extremely dry. Scientists think that there may be a small amount of water, in the form of ice, at the planets poles. The poles never receive direct sunlight. Figure 25.10 shows a diagram of Mercurys interior. Mercury is one of the densest planets. Scientists think that the interior contains a large core made mostly of melted iron. Mercurys core takes up about 42% of the planets volume. Mercurys highly cratered surface is evidence that Mercury is not geologically active. Named after the Roman goddess of love, Venus is the only planet named after a female. Venus is sometimes called Earths sister planet. But just how similar is Venus to Earth? Venus is our nearest neighbor. Venus is most like Earth in size. Viewed through a telescope, Venus looks smooth and featureless. The planet is covered by a thick layer of clouds. You can see the clouds in pictures of Venus, such as Figure 25.11. We make maps of the surface using radar, because the thick clouds wont allow us to take photographs of the surface of Venus. Figure 25.12 shows the topographical features of Venus. The image was produced by the Magellan probe on a flyby. Radar waves sent by the spacecraft reveal mountains, valleys, vast lava plains, and canyons. Like Mercury, Venus does not have a moon. Clouds on Earth are made of water vapor. Venuss clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide and large amounts of corrosive sulfuric acid! The atmosphere of Venus is so thick that the pressure on the surface of Venus is very high. In fact, it is 90 times greater than the pressure at Earths surface! The thick atmosphere causes a strong greenhouse effect. As a result, Venus is the hottest planet. Even though it is farther from the Sun, Venus is much hotter even than Mercury. Temperatures at the surface reach 465C (860F). Thats hot enough to melt lead! Venus has more volcanoes than any other planet. There are between 100,000 and one million volcanoes on Venus! Most of the volcanoes are now inactive. There are also a large number of craters. This means
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hottest of all the planets in the solar system
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Mercury is the smallest planet. It has no moon. The planet is also closest to the Sun and appears in Figure 25.7. As Figure 25.8 shows, the surface of Mercury is covered with craters, like Earths Moon. The presence of impact craters that are so old means that Mercury hasnt changed much geologically for billions of years. With only a trace of an atmosphere, it has no weather to wear down the ancient craters. Because Mercury is so close to the Sun, it is difficult to observe from Earth, even with a telescope. The Mariner 10 spacecraft did a flyby of Mercury in 19741975, which was the best data from the planet for decades. In 2004, the MESSENGER mission left Earth. On its way to Mercury it did one flyby of Earth, two of Venus and three of Mercury. In March 2011, MESSENGER became the first spacecraft to enter an orbit around Mercury. During its year-long mission, the craft will map the planets surface and conduct other studies. One of these images can be seen in Figure 25.9. Mercury is named for the Roman messenger god. Mercury was a messenger because he could run extremely fast. The Greeks gave the planet this name because Mercury moves very quickly in its orbit around the Sun. Mercury orbits the Sun in just 88 Earth days. Mercury has a very short year, but it also has very long days. Mercury rotates slowly on its axis, turning exactly three times for every two times it orbits the Sun. Therefore, each day on Mercury is 58 Earth days long. Mercury is very close to the Sun, so it can get very hot. Mercury also has virtually no atmosphere. As the planet rotates very slowly, the temperature varies tremendously. In direct sunlight, the surface can be as hot as 427C (801F). On the dark side, the surface can be as cold as 183C (297F)! The coldest temperatures may be on the insides of craters. Most of Mercury is extremely dry. Scientists think that there may be a small amount of water, in the form of ice, at the planets poles. The poles never receive direct sunlight. Figure 25.10 shows a diagram of Mercurys interior. Mercury is one of the densest planets. Scientists think that the interior contains a large core made mostly of melted iron. Mercurys core takes up about 42% of the planets volume. Mercurys highly cratered surface is evidence that Mercury is not geologically active. Named after the Roman goddess of love, Venus is the only planet named after a female. Venus is sometimes called Earths sister planet. But just how similar is Venus to Earth? Venus is our nearest neighbor. Venus is most like Earth in size. Viewed through a telescope, Venus looks smooth and featureless. The planet is covered by a thick layer of clouds. You can see the clouds in pictures of Venus, such as Figure 25.11. We make maps of the surface using radar, because the thick clouds wont allow us to take photographs of the surface of Venus. Figure 25.12 shows the topographical features of Venus. The image was produced by the Magellan probe on a flyby. Radar waves sent by the spacecraft reveal mountains, valleys, vast lava plains, and canyons. Like Mercury, Venus does not have a moon. Clouds on Earth are made of water vapor. Venuss clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide and large amounts of corrosive sulfuric acid! The atmosphere of Venus is so thick that the pressure on the surface of Venus is very high. In fact, it is 90 times greater than the pressure at Earths surface! The thick atmosphere causes a strong greenhouse effect. As a result, Venus is the hottest planet. Even though it is farther from the Sun, Venus is much hotter even than Mercury. Temperatures at the surface reach 465C (860F). Thats hot enough to melt lead! Venus has more volcanoes than any other planet. There are between 100,000 and one million volcanoes on Venus! Most of the volcanoes are now inactive. There are also a large number of craters. This means
|
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Mercury is the smallest planet. It has no moon. The planet is also closest to the Sun and appears in Figure 25.7. As Figure 25.8 shows, the surface of Mercury is covered with craters, like Earths Moon. The presence of impact craters that are so old means that Mercury hasnt changed much geologically for billions of years. With only a trace of an atmosphere, it has no weather to wear down the ancient craters. Because Mercury is so close to the Sun, it is difficult to observe from Earth, even with a telescope. The Mariner 10 spacecraft did a flyby of Mercury in 19741975, which was the best data from the planet for decades. In 2004, the MESSENGER mission left Earth. On its way to Mercury it did one flyby of Earth, two of Venus and three of Mercury. In March 2011, MESSENGER became the first spacecraft to enter an orbit around Mercury. During its year-long mission, the craft will map the planets surface and conduct other studies. One of these images can be seen in Figure 25.9. Mercury is named for the Roman messenger god. Mercury was a messenger because he could run extremely fast. The Greeks gave the planet this name because Mercury moves very quickly in its orbit around the Sun. Mercury orbits the Sun in just 88 Earth days. Mercury has a very short year, but it also has very long days. Mercury rotates slowly on its axis, turning exactly three times for every two times it orbits the Sun. Therefore, each day on Mercury is 58 Earth days long. Mercury is very close to the Sun, so it can get very hot. Mercury also has virtually no atmosphere. As the planet rotates very slowly, the temperature varies tremendously. In direct sunlight, the surface can be as hot as 427C (801F). On the dark side, the surface can be as cold as 183C (297F)! The coldest temperatures may be on the insides of craters. Most of Mercury is extremely dry. Scientists think that there may be a small amount of water, in the form of ice, at the planets poles. The poles never receive direct sunlight. Figure 25.10 shows a diagram of Mercurys interior. Mercury is one of the densest planets. Scientists think that the interior contains a large core made mostly of melted iron. Mercurys core takes up about 42% of the planets volume. Mercurys highly cratered surface is evidence that Mercury is not geologically active. Named after the Roman goddess of love, Venus is the only planet named after a female. Venus is sometimes called Earths sister planet. But just how similar is Venus to Earth? Venus is our nearest neighbor. Venus is most like Earth in size. Viewed through a telescope, Venus looks smooth and featureless. The planet is covered by a thick layer of clouds. You can see the clouds in pictures of Venus, such as Figure 25.11. We make maps of the surface using radar, because the thick clouds wont allow us to take photographs of the surface of Venus. Figure 25.12 shows the topographical features of Venus. The image was produced by the Magellan probe on a flyby. Radar waves sent by the spacecraft reveal mountains, valleys, vast lava plains, and canyons. Like Mercury, Venus does not have a moon. Clouds on Earth are made of water vapor. Venuss clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide and large amounts of corrosive sulfuric acid! The atmosphere of Venus is so thick that the pressure on the surface of Venus is very high. In fact, it is 90 times greater than the pressure at Earths surface! The thick atmosphere causes a strong greenhouse effect. As a result, Venus is the hottest planet. Even though it is farther from the Sun, Venus is much hotter even than Mercury. Temperatures at the surface reach 465C (860F). Thats hot enough to melt lead! Venus has more volcanoes than any other planet. There are between 100,000 and one million volcanoes on Venus! Most of the volcanoes are now inactive. There are also a large number of craters. This means
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smallest of all the planets in the solar system
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Mercury is the smallest planet. It has no moon. The planet is also closest to the Sun and appears in Figure 25.7. As Figure 25.8 shows, the surface of Mercury is covered with craters, like Earths Moon. The presence of impact craters that are so old means that Mercury hasnt changed much geologically for billions of years. With only a trace of an atmosphere, it has no weather to wear down the ancient craters. Because Mercury is so close to the Sun, it is difficult to observe from Earth, even with a telescope. The Mariner 10 spacecraft did a flyby of Mercury in 19741975, which was the best data from the planet for decades. In 2004, the MESSENGER mission left Earth. On its way to Mercury it did one flyby of Earth, two of Venus and three of Mercury. In March 2011, MESSENGER became the first spacecraft to enter an orbit around Mercury. During its year-long mission, the craft will map the planets surface and conduct other studies. One of these images can be seen in Figure 25.9. Mercury is named for the Roman messenger god. Mercury was a messenger because he could run extremely fast. The Greeks gave the planet this name because Mercury moves very quickly in its orbit around the Sun. Mercury orbits the Sun in just 88 Earth days. Mercury has a very short year, but it also has very long days. Mercury rotates slowly on its axis, turning exactly three times for every two times it orbits the Sun. Therefore, each day on Mercury is 58 Earth days long. Mercury is very close to the Sun, so it can get very hot. Mercury also has virtually no atmosphere. As the planet rotates very slowly, the temperature varies tremendously. In direct sunlight, the surface can be as hot as 427C (801F). On the dark side, the surface can be as cold as 183C (297F)! The coldest temperatures may be on the insides of craters. Most of Mercury is extremely dry. Scientists think that there may be a small amount of water, in the form of ice, at the planets poles. The poles never receive direct sunlight. Figure 25.10 shows a diagram of Mercurys interior. Mercury is one of the densest planets. Scientists think that the interior contains a large core made mostly of melted iron. Mercurys core takes up about 42% of the planets volume. Mercurys highly cratered surface is evidence that Mercury is not geologically active. Named after the Roman goddess of love, Venus is the only planet named after a female. Venus is sometimes called Earths sister planet. But just how similar is Venus to Earth? Venus is our nearest neighbor. Venus is most like Earth in size. Viewed through a telescope, Venus looks smooth and featureless. The planet is covered by a thick layer of clouds. You can see the clouds in pictures of Venus, such as Figure 25.11. We make maps of the surface using radar, because the thick clouds wont allow us to take photographs of the surface of Venus. Figure 25.12 shows the topographical features of Venus. The image was produced by the Magellan probe on a flyby. Radar waves sent by the spacecraft reveal mountains, valleys, vast lava plains, and canyons. Like Mercury, Venus does not have a moon. Clouds on Earth are made of water vapor. Venuss clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide and large amounts of corrosive sulfuric acid! The atmosphere of Venus is so thick that the pressure on the surface of Venus is very high. In fact, it is 90 times greater than the pressure at Earths surface! The thick atmosphere causes a strong greenhouse effect. As a result, Venus is the hottest planet. Even though it is farther from the Sun, Venus is much hotter even than Mercury. Temperatures at the surface reach 465C (860F). Thats hot enough to melt lead! Venus has more volcanoes than any other planet. There are between 100,000 and one million volcanoes on Venus! Most of the volcanoes are now inactive. There are also a large number of craters. This means
|
spacecraft that is orbiting and studying Mercury
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Mercury is the smallest planet. It has no moon. The planet is also closest to the Sun and appears in Figure 25.7. As Figure 25.8 shows, the surface of Mercury is covered with craters, like Earths Moon. The presence of impact craters that are so old means that Mercury hasnt changed much geologically for billions of years. With only a trace of an atmosphere, it has no weather to wear down the ancient craters. Because Mercury is so close to the Sun, it is difficult to observe from Earth, even with a telescope. The Mariner 10 spacecraft did a flyby of Mercury in 19741975, which was the best data from the planet for decades. In 2004, the MESSENGER mission left Earth. On its way to Mercury it did one flyby of Earth, two of Venus and three of Mercury. In March 2011, MESSENGER became the first spacecraft to enter an orbit around Mercury. During its year-long mission, the craft will map the planets surface and conduct other studies. One of these images can be seen in Figure 25.9. Mercury is named for the Roman messenger god. Mercury was a messenger because he could run extremely fast. The Greeks gave the planet this name because Mercury moves very quickly in its orbit around the Sun. Mercury orbits the Sun in just 88 Earth days. Mercury has a very short year, but it also has very long days. Mercury rotates slowly on its axis, turning exactly three times for every two times it orbits the Sun. Therefore, each day on Mercury is 58 Earth days long. Mercury is very close to the Sun, so it can get very hot. Mercury also has virtually no atmosphere. As the planet rotates very slowly, the temperature varies tremendously. In direct sunlight, the surface can be as hot as 427C (801F). On the dark side, the surface can be as cold as 183C (297F)! The coldest temperatures may be on the insides of craters. Most of Mercury is extremely dry. Scientists think that there may be a small amount of water, in the form of ice, at the planets poles. The poles never receive direct sunlight. Figure 25.10 shows a diagram of Mercurys interior. Mercury is one of the densest planets. Scientists think that the interior contains a large core made mostly of melted iron. Mercurys core takes up about 42% of the planets volume. Mercurys highly cratered surface is evidence that Mercury is not geologically active. Named after the Roman goddess of love, Venus is the only planet named after a female. Venus is sometimes called Earths sister planet. But just how similar is Venus to Earth? Venus is our nearest neighbor. Venus is most like Earth in size. Viewed through a telescope, Venus looks smooth and featureless. The planet is covered by a thick layer of clouds. You can see the clouds in pictures of Venus, such as Figure 25.11. We make maps of the surface using radar, because the thick clouds wont allow us to take photographs of the surface of Venus. Figure 25.12 shows the topographical features of Venus. The image was produced by the Magellan probe on a flyby. Radar waves sent by the spacecraft reveal mountains, valleys, vast lava plains, and canyons. Like Mercury, Venus does not have a moon. Clouds on Earth are made of water vapor. Venuss clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide and large amounts of corrosive sulfuric acid! The atmosphere of Venus is so thick that the pressure on the surface of Venus is very high. In fact, it is 90 times greater than the pressure at Earths surface! The thick atmosphere causes a strong greenhouse effect. As a result, Venus is the hottest planet. Even though it is farther from the Sun, Venus is much hotter even than Mercury. Temperatures at the surface reach 465C (860F). Thats hot enough to melt lead! Venus has more volcanoes than any other planet. There are between 100,000 and one million volcanoes on Venus! Most of the volcanoes are now inactive. There are also a large number of craters. This means
|
The inner planet with an average surface temperature of 14 C is
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Mercury is the smallest planet. It has no moon. The planet is also closest to the Sun and appears in Figure 25.7. As Figure 25.8 shows, the surface of Mercury is covered with craters, like Earths Moon. The presence of impact craters that are so old means that Mercury hasnt changed much geologically for billions of years. With only a trace of an atmosphere, it has no weather to wear down the ancient craters. Because Mercury is so close to the Sun, it is difficult to observe from Earth, even with a telescope. The Mariner 10 spacecraft did a flyby of Mercury in 19741975, which was the best data from the planet for decades. In 2004, the MESSENGER mission left Earth. On its way to Mercury it did one flyby of Earth, two of Venus and three of Mercury. In March 2011, MESSENGER became the first spacecraft to enter an orbit around Mercury. During its year-long mission, the craft will map the planets surface and conduct other studies. One of these images can be seen in Figure 25.9. Mercury is named for the Roman messenger god. Mercury was a messenger because he could run extremely fast. The Greeks gave the planet this name because Mercury moves very quickly in its orbit around the Sun. Mercury orbits the Sun in just 88 Earth days. Mercury has a very short year, but it also has very long days. Mercury rotates slowly on its axis, turning exactly three times for every two times it orbits the Sun. Therefore, each day on Mercury is 58 Earth days long. Mercury is very close to the Sun, so it can get very hot. Mercury also has virtually no atmosphere. As the planet rotates very slowly, the temperature varies tremendously. In direct sunlight, the surface can be as hot as 427C (801F). On the dark side, the surface can be as cold as 183C (297F)! The coldest temperatures may be on the insides of craters. Most of Mercury is extremely dry. Scientists think that there may be a small amount of water, in the form of ice, at the planets poles. The poles never receive direct sunlight. Figure 25.10 shows a diagram of Mercurys interior. Mercury is one of the densest planets. Scientists think that the interior contains a large core made mostly of melted iron. Mercurys core takes up about 42% of the planets volume. Mercurys highly cratered surface is evidence that Mercury is not geologically active. Named after the Roman goddess of love, Venus is the only planet named after a female. Venus is sometimes called Earths sister planet. But just how similar is Venus to Earth? Venus is our nearest neighbor. Venus is most like Earth in size. Viewed through a telescope, Venus looks smooth and featureless. The planet is covered by a thick layer of clouds. You can see the clouds in pictures of Venus, such as Figure 25.11. We make maps of the surface using radar, because the thick clouds wont allow us to take photographs of the surface of Venus. Figure 25.12 shows the topographical features of Venus. The image was produced by the Magellan probe on a flyby. Radar waves sent by the spacecraft reveal mountains, valleys, vast lava plains, and canyons. Like Mercury, Venus does not have a moon. Clouds on Earth are made of water vapor. Venuss clouds are a lot less pleasant. They are made of carbon dioxide, sulfur dioxide and large amounts of corrosive sulfuric acid! The atmosphere of Venus is so thick that the pressure on the surface of Venus is very high. In fact, it is 90 times greater than the pressure at Earths surface! The thick atmosphere causes a strong greenhouse effect. As a result, Venus is the hottest planet. Even though it is farther from the Sun, Venus is much hotter even than Mercury. Temperatures at the surface reach 465C (860F). Thats hot enough to melt lead! Venus has more volcanoes than any other planet. There are between 100,000 and one million volcanoes on Venus! Most of the volcanoes are now inactive. There are also a large number of craters. This means
|
Which process explains why Venus is very hot?
|
[
"greenhouse effect"
] |
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Different rock types weather at different rates. Certain types of rock are very resistant to weathering. Igneous rocks, especially intrusive igneous rocks such as granite, weather slowly because it is hard for water to penetrate them. Other types of rock, such as limestone, are easily weathered because they dissolve in weak acids. Rocks that resist weathering remain at the surface and form ridges or hills. Shiprock in New Mexico is the throat of a volcano thats left after the rest of the volcano eroded away. The rock thats left behind is magma that cooled relatively slowly and is harder than the rock that had surrounded it. Different minerals also weather at different rates. Some minerals in a rock might completely dissolve in water, but the more resistant minerals remain. In this case, the rocks surface becomes pitted and rough. When a less resistant mineral dissolves, more resistant mineral grains are released from the rock. A beautiful example of this effect is the "Stone Forest" in China, see the video below: The Shiprock formation in northwest New Mexico is the central plug of resistant lava from which the surrounding rock weath- ered and eroded away. Click image to the left or use the URL below. URL: A regions climate strongly influences weathering. Climate is determined by the temperature of a region plus the amount of precipitation it receives. Climate is weather averaged over a long period of time. Chemical weathering increases as: Temperature increases: Chemical reactions proceed more rapidly at higher temperatures. For each 10o C increase in average temperature, the rate of chemical reactions doubles. Precipitation increases: More water allows more chemical reactions. Since water participates in both mechan- ical and chemical weathering, more water strongly increases weathering. So how do different climates influence weathering? A cold, dry climate will produce the lowest rate of weathering. A warm, wet climate will produce the highest rate of weathering. The warmer a climate is, the more types of vegetation it will have and the greater the rate of biological weathering (Figure 1.2). This happens because plants and bacteria grow and multiply faster in warmer temperatures. Some resources are concentrated by weathering processes. In tropical climates, intense chemical weathering carries away all soluble minerals, leaving behind just the least soluble components. The aluminum oxide, bauxite, forms this way and is our main source of aluminum ore.
|
climate is determined by
|
[
"temperature"
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Carbon is one of the most common elements found in living organisms. Chains of carbon molecules form the backbones of many organic molecules, such as carbohydrates, proteins, and lipids. Carbon is constantly cycling between living organisms and the atmosphere ( Figure 1.1). The cycling of carbon occurs through the carbon cycle. Living organisms cannot make their own carbon, so how is carbon incorporated into living organisms? In the atmosphere, carbon is in the form of carbon dioxide gas (CO2 ). Recall that plants and other producers capture the carbon dioxide and convert it to glucose (C6 H12 O6 ) through the process of photosynthesis. Then as animals eat plants or other animals, they gain the carbon from those organisms. The chemical equation of photosynthesis is 6CO2 + 6H2 O C6 H12 O6 + 6O2 . How does this carbon in living things end up back in the atmosphere? Remember that we breathe out carbon dioxide. This carbon dioxide is generated through the process of cellular respiration, which has the reverse chemical reaction as photosynthesis. That means when our cells burn food (glucose) for energy, carbon dioxide is released. We, like all animals, exhale this carbon dioxide and return it back to the atmosphere. Also, carbon is released to the atmosphere as an organism dies and decomposes. Cellular respiration and photosynthesis can be described as a cycle, as one uses carbon dioxide (and water) and makes oxygen (and glucose), and the other uses oxygen (and glucose) and makes carbon dioxide (and water). The carbon cycle. The cycling of car- bon dioxide in photosynthesis and cellular respiration are main components of the carbon cycle. Carbon is also returned to the atmosphere by the burning of organic matter (combustion) and fossil fuels and decomposition of organic matter. Millions of years ago, there were so many dead plants and animals that they could not completely decompose before they were buried. They were covered over by soil or sand, tar or ice. These dead plants and animals are organic matter made out of cells full of carbon-containing organic compounds (carbohydrates, lipids, proteins and nucleic acids). What happened to all this carbon? When organic matter is under pressure for millions of years, it forms fossil fuels. Fossil fuels are coal, oil, and natural gas. When humans dig up and use fossil fuels, we have an impact on the carbon cycle ( Figure 1.2). This carbon is not recycled until it is used by humans. The burning of fossil fuels releases more carbon dioxide into the atmosphere than is used by photosynthesis. So, there is more carbon dioxide entering the atmosphere than is coming out of it. Carbon dioxide is known as a greenhouse gas, since it lets in light energy but does not let heat escape, much like the panes of a greenhouse. The increase of greenhouse gasses in the atmosphere is contributing to a global rise in Earths temperature, known as global warming or global climate change.
|
burning of organic matter releases carbon dioxide into the atmosphere. this process is known as
|
[
"combustion."
] |
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Carbon is one of the most common elements found in living organisms. Chains of carbon molecules form the backbones of many organic molecules, such as carbohydrates, proteins, and lipids. Carbon is constantly cycling between living organisms and the atmosphere ( Figure 1.1). The cycling of carbon occurs through the carbon cycle. Living organisms cannot make their own carbon, so how is carbon incorporated into living organisms? In the atmosphere, carbon is in the form of carbon dioxide gas (CO2 ). Recall that plants and other producers capture the carbon dioxide and convert it to glucose (C6 H12 O6 ) through the process of photosynthesis. Then as animals eat plants or other animals, they gain the carbon from those organisms. The chemical equation of photosynthesis is 6CO2 + 6H2 O C6 H12 O6 + 6O2 . How does this carbon in living things end up back in the atmosphere? Remember that we breathe out carbon dioxide. This carbon dioxide is generated through the process of cellular respiration, which has the reverse chemical reaction as photosynthesis. That means when our cells burn food (glucose) for energy, carbon dioxide is released. We, like all animals, exhale this carbon dioxide and return it back to the atmosphere. Also, carbon is released to the atmosphere as an organism dies and decomposes. Cellular respiration and photosynthesis can be described as a cycle, as one uses carbon dioxide (and water) and makes oxygen (and glucose), and the other uses oxygen (and glucose) and makes carbon dioxide (and water). The carbon cycle. The cycling of car- bon dioxide in photosynthesis and cellular respiration are main components of the carbon cycle. Carbon is also returned to the atmosphere by the burning of organic matter (combustion) and fossil fuels and decomposition of organic matter. Millions of years ago, there were so many dead plants and animals that they could not completely decompose before they were buried. They were covered over by soil or sand, tar or ice. These dead plants and animals are organic matter made out of cells full of carbon-containing organic compounds (carbohydrates, lipids, proteins and nucleic acids). What happened to all this carbon? When organic matter is under pressure for millions of years, it forms fossil fuels. Fossil fuels are coal, oil, and natural gas. When humans dig up and use fossil fuels, we have an impact on the carbon cycle ( Figure 1.2). This carbon is not recycled until it is used by humans. The burning of fossil fuels releases more carbon dioxide into the atmosphere than is used by photosynthesis. So, there is more carbon dioxide entering the atmosphere than is coming out of it. Carbon dioxide is known as a greenhouse gas, since it lets in light energy but does not let heat escape, much like the panes of a greenhouse. The increase of greenhouse gasses in the atmosphere is contributing to a global rise in Earths temperature, known as global warming or global climate change.
|
when organisms die, what process returns their carbon back into the atmosphere?
|
[
"decomposition"
] |
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Love Canal gained worldwide attention in the late 1970s when the press started covering its story. The story is outlined below and illustrated in Figure 19.9. The Love Canal disaster actually began back in the mid 1900s. The disaster continues even today. Starting in the early 1940s, a big chemical company put thousands of barrels of chemical waste into an old canal. Over the next 10 years, the company dumped almost 22,000 tons of chemicals into the ground! In the early 1950s, the company covered over the barrels in the canal with soil. Then they sold the land to the city for just a dollar. The city needed the land in order to build an elementary school. The company warned the city that toxic waste was buried there. But they thought the waste was safe. The school and hundreds of homes were also built over the old canal. As it turned out, the cheap price was no bargain. Chemicals started leaking from the barrels. Chemicals seeped into basements. Chemicals bubbled up to the surface of the ground. In some places, plants wouldnt even grow on the soil. People noticed bad smells. Many got sick, especially the children. Residents wanted to know if the old chemicals were the cause. But they had a hard time getting officials to listen. So they demonstrated and demanded answers. Finally, the soil was tested and was found to be contaminated with harmful chemicals. For example, it contained a lot of lead and mercury. Both can cause permanent damage to the human nervous system. The school was closed. More than 200 homes were evacuated. Much of the Love Canal neighborhood was bulldozed away. The area had a massive clean-up effort. The cleanup cost millions of dollars. More than three decades later, much of Love Canal is still too contaminated to be safe for people. Love Canal opened peoples eyes to toxic waste burial. They realized there must be other Love Canals all over the country. Thousands of contaminated sites were found. The Superfund Act was passed in 1980. The law required that money be set aside for cleanup of toxic waste sites, like the Elizabeth Copper Mine in Vermont (see the far-right image in Figure 19.9). The law also required safer disposal of hazardous waste in the future. Love Canal highlighted the problem of pollution by hazardous waste. Hazardous waste is any waste that is dangerous to the health of people or the environment. It may be dangerous because it is toxic, corrosive, flammable, or explosive. Toxic waste is poisonous. Toxic waste may cause cancer or birth defects in people. It may also harm other living things. Corrosive waste is highly reactive with other substances. Corrosive waste may cause burns or destroy other materials that it touches. Flammable waste can burn easily. It may also give off harmful fumes when it burns. Explosive waste is likely to explode. The risk of explosion may be greater if the waste is mixed with other substances. Table 19.1 shows some examples of hazardous waste. Look closely. Are any of these examples lurking around your home? Example Description Cars contain toxic fluids such as brake fluid. The fluids may also be corrosive and flammable. This photo shows one way the fluids can end up in the ground. Cars use gas and oil. These materials are toxic and flammable. They pollute the land when they leak or spill. Batteries contain toxic and corrosive materials. People often toss them in the trash, but they should be disposed of properly. Electronics, such as old computers, contain toxic chem- icals. They may be sent to landfills where the toxic materials end up in the ground. Medical waste can contain many hazards: Human body fluids may cause disease; old thermometers may contain toxic mercury; and pharmaceuticals may be toxic to people and other living things. Example Description Paints can be both toxic and flammable. Paints may spill on the ground or be thrown improperly in the trash. Chemicals are applied to farm fields and lawns. They include fertilizers, herbicides, and pesticides. Many of these chemicals are toxic to people and other animals. The greatest source of hazardous waste is industry. Agriculture is another major
|
Nations that produce the most hazardous waste have the most
|
[
"industry"
] |
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Love Canal gained worldwide attention in the late 1970s when the press started covering its story. The story is outlined below and illustrated in Figure 19.9. The Love Canal disaster actually began back in the mid 1900s. The disaster continues even today. Starting in the early 1940s, a big chemical company put thousands of barrels of chemical waste into an old canal. Over the next 10 years, the company dumped almost 22,000 tons of chemicals into the ground! In the early 1950s, the company covered over the barrels in the canal with soil. Then they sold the land to the city for just a dollar. The city needed the land in order to build an elementary school. The company warned the city that toxic waste was buried there. But they thought the waste was safe. The school and hundreds of homes were also built over the old canal. As it turned out, the cheap price was no bargain. Chemicals started leaking from the barrels. Chemicals seeped into basements. Chemicals bubbled up to the surface of the ground. In some places, plants wouldnt even grow on the soil. People noticed bad smells. Many got sick, especially the children. Residents wanted to know if the old chemicals were the cause. But they had a hard time getting officials to listen. So they demonstrated and demanded answers. Finally, the soil was tested and was found to be contaminated with harmful chemicals. For example, it contained a lot of lead and mercury. Both can cause permanent damage to the human nervous system. The school was closed. More than 200 homes were evacuated. Much of the Love Canal neighborhood was bulldozed away. The area had a massive clean-up effort. The cleanup cost millions of dollars. More than three decades later, much of Love Canal is still too contaminated to be safe for people. Love Canal opened peoples eyes to toxic waste burial. They realized there must be other Love Canals all over the country. Thousands of contaminated sites were found. The Superfund Act was passed in 1980. The law required that money be set aside for cleanup of toxic waste sites, like the Elizabeth Copper Mine in Vermont (see the far-right image in Figure 19.9). The law also required safer disposal of hazardous waste in the future. Love Canal highlighted the problem of pollution by hazardous waste. Hazardous waste is any waste that is dangerous to the health of people or the environment. It may be dangerous because it is toxic, corrosive, flammable, or explosive. Toxic waste is poisonous. Toxic waste may cause cancer or birth defects in people. It may also harm other living things. Corrosive waste is highly reactive with other substances. Corrosive waste may cause burns or destroy other materials that it touches. Flammable waste can burn easily. It may also give off harmful fumes when it burns. Explosive waste is likely to explode. The risk of explosion may be greater if the waste is mixed with other substances. Table 19.1 shows some examples of hazardous waste. Look closely. Are any of these examples lurking around your home? Example Description Cars contain toxic fluids such as brake fluid. The fluids may also be corrosive and flammable. This photo shows one way the fluids can end up in the ground. Cars use gas and oil. These materials are toxic and flammable. They pollute the land when they leak or spill. Batteries contain toxic and corrosive materials. People often toss them in the trash, but they should be disposed of properly. Electronics, such as old computers, contain toxic chem- icals. They may be sent to landfills where the toxic materials end up in the ground. Medical waste can contain many hazards: Human body fluids may cause disease; old thermometers may contain toxic mercury; and pharmaceuticals may be toxic to people and other living things. Example Description Paints can be both toxic and flammable. Paints may spill on the ground or be thrown improperly in the trash. Chemicals are applied to farm fields and lawns. They include fertilizers, herbicides, and pesticides. Many of these chemicals are toxic to people and other animals. The greatest source of hazardous waste is industry. Agriculture is another major
|
The Love Canal disaster began with the disposal of chemical wastes in a canal in the
|
[
"1940s."
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Love Canal gained worldwide attention in the late 1970s when the press started covering its story. The story is outlined below and illustrated in Figure 19.9. The Love Canal disaster actually began back in the mid 1900s. The disaster continues even today. Starting in the early 1940s, a big chemical company put thousands of barrels of chemical waste into an old canal. Over the next 10 years, the company dumped almost 22,000 tons of chemicals into the ground! In the early 1950s, the company covered over the barrels in the canal with soil. Then they sold the land to the city for just a dollar. The city needed the land in order to build an elementary school. The company warned the city that toxic waste was buried there. But they thought the waste was safe. The school and hundreds of homes were also built over the old canal. As it turned out, the cheap price was no bargain. Chemicals started leaking from the barrels. Chemicals seeped into basements. Chemicals bubbled up to the surface of the ground. In some places, plants wouldnt even grow on the soil. People noticed bad smells. Many got sick, especially the children. Residents wanted to know if the old chemicals were the cause. But they had a hard time getting officials to listen. So they demonstrated and demanded answers. Finally, the soil was tested and was found to be contaminated with harmful chemicals. For example, it contained a lot of lead and mercury. Both can cause permanent damage to the human nervous system. The school was closed. More than 200 homes were evacuated. Much of the Love Canal neighborhood was bulldozed away. The area had a massive clean-up effort. The cleanup cost millions of dollars. More than three decades later, much of Love Canal is still too contaminated to be safe for people. Love Canal opened peoples eyes to toxic waste burial. They realized there must be other Love Canals all over the country. Thousands of contaminated sites were found. The Superfund Act was passed in 1980. The law required that money be set aside for cleanup of toxic waste sites, like the Elizabeth Copper Mine in Vermont (see the far-right image in Figure 19.9). The law also required safer disposal of hazardous waste in the future. Love Canal highlighted the problem of pollution by hazardous waste. Hazardous waste is any waste that is dangerous to the health of people or the environment. It may be dangerous because it is toxic, corrosive, flammable, or explosive. Toxic waste is poisonous. Toxic waste may cause cancer or birth defects in people. It may also harm other living things. Corrosive waste is highly reactive with other substances. Corrosive waste may cause burns or destroy other materials that it touches. Flammable waste can burn easily. It may also give off harmful fumes when it burns. Explosive waste is likely to explode. The risk of explosion may be greater if the waste is mixed with other substances. Table 19.1 shows some examples of hazardous waste. Look closely. Are any of these examples lurking around your home? Example Description Cars contain toxic fluids such as brake fluid. The fluids may also be corrosive and flammable. This photo shows one way the fluids can end up in the ground. Cars use gas and oil. These materials are toxic and flammable. They pollute the land when they leak or spill. Batteries contain toxic and corrosive materials. People often toss them in the trash, but they should be disposed of properly. Electronics, such as old computers, contain toxic chem- icals. They may be sent to landfills where the toxic materials end up in the ground. Medical waste can contain many hazards: Human body fluids may cause disease; old thermometers may contain toxic mercury; and pharmaceuticals may be toxic to people and other living things. Example Description Paints can be both toxic and flammable. Paints may spill on the ground or be thrown improperly in the trash. Chemicals are applied to farm fields and lawns. They include fertilizers, herbicides, and pesticides. Many of these chemicals are toxic to people and other animals. The greatest source of hazardous waste is industry. Agriculture is another major
|
highly reactive with other substances
|
[
"corrosive"
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Love Canal gained worldwide attention in the late 1970s when the press started covering its story. The story is outlined below and illustrated in Figure 19.9. The Love Canal disaster actually began back in the mid 1900s. The disaster continues even today. Starting in the early 1940s, a big chemical company put thousands of barrels of chemical waste into an old canal. Over the next 10 years, the company dumped almost 22,000 tons of chemicals into the ground! In the early 1950s, the company covered over the barrels in the canal with soil. Then they sold the land to the city for just a dollar. The city needed the land in order to build an elementary school. The company warned the city that toxic waste was buried there. But they thought the waste was safe. The school and hundreds of homes were also built over the old canal. As it turned out, the cheap price was no bargain. Chemicals started leaking from the barrels. Chemicals seeped into basements. Chemicals bubbled up to the surface of the ground. In some places, plants wouldnt even grow on the soil. People noticed bad smells. Many got sick, especially the children. Residents wanted to know if the old chemicals were the cause. But they had a hard time getting officials to listen. So they demonstrated and demanded answers. Finally, the soil was tested and was found to be contaminated with harmful chemicals. For example, it contained a lot of lead and mercury. Both can cause permanent damage to the human nervous system. The school was closed. More than 200 homes were evacuated. Much of the Love Canal neighborhood was bulldozed away. The area had a massive clean-up effort. The cleanup cost millions of dollars. More than three decades later, much of Love Canal is still too contaminated to be safe for people. Love Canal opened peoples eyes to toxic waste burial. They realized there must be other Love Canals all over the country. Thousands of contaminated sites were found. The Superfund Act was passed in 1980. The law required that money be set aside for cleanup of toxic waste sites, like the Elizabeth Copper Mine in Vermont (see the far-right image in Figure 19.9). The law also required safer disposal of hazardous waste in the future. Love Canal highlighted the problem of pollution by hazardous waste. Hazardous waste is any waste that is dangerous to the health of people or the environment. It may be dangerous because it is toxic, corrosive, flammable, or explosive. Toxic waste is poisonous. Toxic waste may cause cancer or birth defects in people. It may also harm other living things. Corrosive waste is highly reactive with other substances. Corrosive waste may cause burns or destroy other materials that it touches. Flammable waste can burn easily. It may also give off harmful fumes when it burns. Explosive waste is likely to explode. The risk of explosion may be greater if the waste is mixed with other substances. Table 19.1 shows some examples of hazardous waste. Look closely. Are any of these examples lurking around your home? Example Description Cars contain toxic fluids such as brake fluid. The fluids may also be corrosive and flammable. This photo shows one way the fluids can end up in the ground. Cars use gas and oil. These materials are toxic and flammable. They pollute the land when they leak or spill. Batteries contain toxic and corrosive materials. People often toss them in the trash, but they should be disposed of properly. Electronics, such as old computers, contain toxic chem- icals. They may be sent to landfills where the toxic materials end up in the ground. Medical waste can contain many hazards: Human body fluids may cause disease; old thermometers may contain toxic mercury; and pharmaceuticals may be toxic to people and other living things. Example Description Paints can be both toxic and flammable. Paints may spill on the ground or be thrown improperly in the trash. Chemicals are applied to farm fields and lawns. They include fertilizers, herbicides, and pesticides. Many of these chemicals are toxic to people and other animals. The greatest source of hazardous waste is industry. Agriculture is another major
|
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Love Canal gained worldwide attention in the late 1970s when the press started covering its story. The story is outlined below and illustrated in Figure 19.9. The Love Canal disaster actually began back in the mid 1900s. The disaster continues even today. Starting in the early 1940s, a big chemical company put thousands of barrels of chemical waste into an old canal. Over the next 10 years, the company dumped almost 22,000 tons of chemicals into the ground! In the early 1950s, the company covered over the barrels in the canal with soil. Then they sold the land to the city for just a dollar. The city needed the land in order to build an elementary school. The company warned the city that toxic waste was buried there. But they thought the waste was safe. The school and hundreds of homes were also built over the old canal. As it turned out, the cheap price was no bargain. Chemicals started leaking from the barrels. Chemicals seeped into basements. Chemicals bubbled up to the surface of the ground. In some places, plants wouldnt even grow on the soil. People noticed bad smells. Many got sick, especially the children. Residents wanted to know if the old chemicals were the cause. But they had a hard time getting officials to listen. So they demonstrated and demanded answers. Finally, the soil was tested and was found to be contaminated with harmful chemicals. For example, it contained a lot of lead and mercury. Both can cause permanent damage to the human nervous system. The school was closed. More than 200 homes were evacuated. Much of the Love Canal neighborhood was bulldozed away. The area had a massive clean-up effort. The cleanup cost millions of dollars. More than three decades later, much of Love Canal is still too contaminated to be safe for people. Love Canal opened peoples eyes to toxic waste burial. They realized there must be other Love Canals all over the country. Thousands of contaminated sites were found. The Superfund Act was passed in 1980. The law required that money be set aside for cleanup of toxic waste sites, like the Elizabeth Copper Mine in Vermont (see the far-right image in Figure 19.9). The law also required safer disposal of hazardous waste in the future. Love Canal highlighted the problem of pollution by hazardous waste. Hazardous waste is any waste that is dangerous to the health of people or the environment. It may be dangerous because it is toxic, corrosive, flammable, or explosive. Toxic waste is poisonous. Toxic waste may cause cancer or birth defects in people. It may also harm other living things. Corrosive waste is highly reactive with other substances. Corrosive waste may cause burns or destroy other materials that it touches. Flammable waste can burn easily. It may also give off harmful fumes when it burns. Explosive waste is likely to explode. The risk of explosion may be greater if the waste is mixed with other substances. Table 19.1 shows some examples of hazardous waste. Look closely. Are any of these examples lurking around your home? Example Description Cars contain toxic fluids such as brake fluid. The fluids may also be corrosive and flammable. This photo shows one way the fluids can end up in the ground. Cars use gas and oil. These materials are toxic and flammable. They pollute the land when they leak or spill. Batteries contain toxic and corrosive materials. People often toss them in the trash, but they should be disposed of properly. Electronics, such as old computers, contain toxic chem- icals. They may be sent to landfills where the toxic materials end up in the ground. Medical waste can contain many hazards: Human body fluids may cause disease; old thermometers may contain toxic mercury; and pharmaceuticals may be toxic to people and other living things. Example Description Paints can be both toxic and flammable. Paints may spill on the ground or be thrown improperly in the trash. Chemicals are applied to farm fields and lawns. They include fertilizers, herbicides, and pesticides. Many of these chemicals are toxic to people and other animals. The greatest source of hazardous waste is industry. Agriculture is another major
|
any waste that is dangerous to people or the environment
|
[
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}
] |
Love Canal gained worldwide attention in the late 1970s when the press started covering its story. The story is outlined below and illustrated in Figure 19.9. The Love Canal disaster actually began back in the mid 1900s. The disaster continues even today. Starting in the early 1940s, a big chemical company put thousands of barrels of chemical waste into an old canal. Over the next 10 years, the company dumped almost 22,000 tons of chemicals into the ground! In the early 1950s, the company covered over the barrels in the canal with soil. Then they sold the land to the city for just a dollar. The city needed the land in order to build an elementary school. The company warned the city that toxic waste was buried there. But they thought the waste was safe. The school and hundreds of homes were also built over the old canal. As it turned out, the cheap price was no bargain. Chemicals started leaking from the barrels. Chemicals seeped into basements. Chemicals bubbled up to the surface of the ground. In some places, plants wouldnt even grow on the soil. People noticed bad smells. Many got sick, especially the children. Residents wanted to know if the old chemicals were the cause. But they had a hard time getting officials to listen. So they demonstrated and demanded answers. Finally, the soil was tested and was found to be contaminated with harmful chemicals. For example, it contained a lot of lead and mercury. Both can cause permanent damage to the human nervous system. The school was closed. More than 200 homes were evacuated. Much of the Love Canal neighborhood was bulldozed away. The area had a massive clean-up effort. The cleanup cost millions of dollars. More than three decades later, much of Love Canal is still too contaminated to be safe for people. Love Canal opened peoples eyes to toxic waste burial. They realized there must be other Love Canals all over the country. Thousands of contaminated sites were found. The Superfund Act was passed in 1980. The law required that money be set aside for cleanup of toxic waste sites, like the Elizabeth Copper Mine in Vermont (see the far-right image in Figure 19.9). The law also required safer disposal of hazardous waste in the future. Love Canal highlighted the problem of pollution by hazardous waste. Hazardous waste is any waste that is dangerous to the health of people or the environment. It may be dangerous because it is toxic, corrosive, flammable, or explosive. Toxic waste is poisonous. Toxic waste may cause cancer or birth defects in people. It may also harm other living things. Corrosive waste is highly reactive with other substances. Corrosive waste may cause burns or destroy other materials that it touches. Flammable waste can burn easily. It may also give off harmful fumes when it burns. Explosive waste is likely to explode. The risk of explosion may be greater if the waste is mixed with other substances. Table 19.1 shows some examples of hazardous waste. Look closely. Are any of these examples lurking around your home? Example Description Cars contain toxic fluids such as brake fluid. The fluids may also be corrosive and flammable. This photo shows one way the fluids can end up in the ground. Cars use gas and oil. These materials are toxic and flammable. They pollute the land when they leak or spill. Batteries contain toxic and corrosive materials. People often toss them in the trash, but they should be disposed of properly. Electronics, such as old computers, contain toxic chem- icals. They may be sent to landfills where the toxic materials end up in the ground. Medical waste can contain many hazards: Human body fluids may cause disease; old thermometers may contain toxic mercury; and pharmaceuticals may be toxic to people and other living things. Example Description Paints can be both toxic and flammable. Paints may spill on the ground or be thrown improperly in the trash. Chemicals are applied to farm fields and lawns. They include fertilizers, herbicides, and pesticides. Many of these chemicals are toxic to people and other animals. The greatest source of hazardous waste is industry. Agriculture is another major
|
act of contaminating the environment
|
[
"pollution"
] |
4f8ced0aa4774790bcf7abff3215c7cb
|
[
{
"end": [
2265
],
"start": [
2257
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}
] |
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