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TRANSCRIPT
Bellringer
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Warm Clothes Required
Regardless of the season, be sure to bring warm clothes on a hiking trip to western Colorado. Temperatures can drop suddenly. Even when temperatures are warm in the valley, they can be extremely cold in the mountains.
When climbers scale the mountains shown here, they often carry oxygen tanks with them. The air is both thin and cold at altitudes of 4,300 m (14,000 ft) and higher.
1 Compare snowcover on the mountain to snowcover by the lake.
2 Would you expect air to be colder at the altitude of clouds than it is on Earth’s surface? Discuss.
Earth’s Atmosphere LESSON 1
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ThermosphereExosphere
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Focus on Content
Temperature v. Altitude
Earth’s Atmosphere LESSON 1
Bellringer
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Blooms under Glass
Flowers can bloom inside a greenhouse all year long—even during a cold, snowy winter. A greenhouse traps energy from the Sun very effectively.
Energy from the Sun is made of more than just the light you can see. Some of it is infrared energy. This kind of energy warms your skin when you bask in the Sun. It warms the air in a greenhouse too.
1 Compare Earth’s surface and atmosphere to the inside of a greenhouse. How are they alike? How are they different?
2 What would happen to these plants if they were moved outside the greenhouse?
3 Why are temperatures on Earth’s surface important?
Earth’s Atmosphere LESSON 2
25% of radiation isreflected by cloudsand particles.
Solar radiation 100%
50% of radiationreaches and isabsorbed by Earth’ssurface.
20% of radiation isabsorbed by particlesin the atmosphere.
5% of radiation is reflected back by land and sea surface.
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Focus on Content Earth’s Atmosphere LESSON 2
Incoming Solar Radiation
Bellringer
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Billowing Sails
Hundreds of years ago, tall sailing ships carried goods and passengers across the oceans. Winds filled the billowing sails to power these ships on their journeys.
Ship captains knew that ocean winds blow in patterns. They plotted courses that took advantage of bands of strong winds.
1 What is wind? What can wind do?
2 What types of winds blow where you live? Do they form a pattern of any kind? Discuss.
3 A system is made of many parts that interact. Are winds part of a system? Explain.
Earth’s Atmosphere LESSON 3
Polar easterlies
Polar easterlies
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WesterliesWesterlies
Trade windsTrade winds
WesterliesWesterlies
Trade windsTrade winds
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Focus on Content Earth’s Atmosphere
Global Wind Belts
LESSON 3
Bellringer
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The Problem of Pollution
Warsaw is the capital of Poland. It is an old and beautiful city. Yet air pollution is a problem here, as it is in cities all over Earth.
Today, people everywhere are recognizing the problems that pollution causes, and they are trying new ways to solve them. You can be part of the solution, too.
1 What happens to smoke after it is released into the air?
2 How would Warsaw be different without the power plant and smokestack shown in the photo?
3 Describe some of the ways individuals and businesses can help to reduce air pollution.
Earth’s Atmosphere LESSON 4
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Focus on Content Earth’s Atmosphere LESSON 4
Air Quality Trends
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Earth’s Atmosphere Lesson 1 Bellringer Comstock Images/AlamyWarm Clothes Required
The troposphere is the layer of Earth’s atmosphere that is closest to the surface. As the photo illustrates, air temperature tends to decrease with altitude in the troposphere. However, this trend does not apply throughout the atmosphere.
Air pressure also decreases with altitude. When people visit the mountains, the low air pressure causes their lungs to take in less oxygen with every breath. People can become temporarily winded and short of energy. Over time, the body compensates for this difference.
Answers to Questions1 The mountains are covered in snow, but snow is
absent on much of the land near the lake, and the lake is not frozen. Colder temperatures at higher altitudes explain this difference.
2 Yes. Near Earth’s surface, air temperature drops with increasing altitude. Air is quite cold at the altitude of clouds, which is why water vapor condenses there.
Lesson 1 Focus on Content Temperature v. Altitude
Students might argue that the outer layers of the atmosphere are closer to the Sun than the inner layers, and that this is why temperature varies among the layers. Explain that this reasoning is not correct. The Sun is approximately 150 million kilometers away from Earth, and the thickness of the atmosphere is extremely small in comparison. Temperature differences among the layers are due in part to differences in air pressure and gas concentrations.
Lesson 2 Bellringer John A. Rizzo/Getty ImagesBlooms under Glass
Discuss other situations in which thermal energy is trapped. For example, a car with its windows closed can act just like a greenhouse. The surfaces and air inside a car can become extremely hot on a warm, sunny day.
Answers to Questions1 Like the inside of a greenhouse, Earth has plants
growing below a blanket of air that traps heat from the Sun. Unlike a greenhouse, Earth’s atmosphere lacks a glass wall that keeps warm air inside it.
2 The plants would be subject to the weather of the region. If the air temperature dropped too low, the plants might die.
3 Life on Earth depends on a specific range of temperatures. If this range of temperatures were to change, then life would change as well. Changing temperatures also affect glaciers and ice caps. Melted ice raises ocean levels.
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Lesson 2 Focus on Content Doug Menuez/Getty ImagesIncoming Solar Radiation
The amount of solar radiation reflected from Earth’s surface varies from place to place, and even from season to season. Fresh snow reflects about 95 percent of the solar radiation that strikes it, while black asphalt parking lots reflect less than 5 percent of this energy.
Scientists use the term heat islands to describe urban areas. Because buildings and pavement absorb heat, they become hotter than nearby rural lands.
Lesson 3 Bellringer Royalty-Free/CORBISBillowing Sails
Discuss how an ocean journey on a sailing ship could last for months, and that even the best quarters were cramped and lacked modern plumbing and other conveniences. Discuss how discouraging it must have felt to be stuck in the Doldrums, a region near the equator where winds blow weakly, if at all.
Answers to Questions1 Wind is moving air. Wind can power sailboats,
lift a kite, and spin wind turbines, which are used to generate electricity. Strong winds can topple trees.
2 Answers will vary with location. Most places receive a variety of winds, including calm winds, strong winds, and winds that are part of severe storms. Wind patterns often are named, such as nor’easters and Santa Ana winds, or they can be part of severe storms, such as hurricanes and tornados.
3 Yes. Winds blow across Earth’s surface, and winds in one region affect winds elsewhere. Earth’s atmosphere forms a system that surrounds and affects the entire planet.
Lesson 3 Focus on Content Global Wind Belts
Students might notice that the diagram does not explain the wide variety of winds observed on land. The diagram shows global trends in the winds, and these trends apply mostly to winds over the ocean. Landforms are much more varied than the surface of the ocean, and the variation affects the winds that blow over the land.
Lesson 4 Bellringer Andrew Ward/Life File/Getty ImagesThe Problem of Pollution
Modern machines and factories became common in the Industrial Revolution, a period in the late eighteenth and early nineteenth centuries. Coal provided the energy that made the Industrial Revolution possible. Discuss how people’s lives changed during the Industrial Revolution, both
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Teacher Guide
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for the better and for the worse. For example, coal mines employed many people, but the work was dirty and dangerous, and breathing in coal dust caused lung disease. In London and other cities, soot from burning coal formed a thick haze in the air.
Answers to Questions1 The wind carries smoke and spreads it over a
wide area. Eventually the smoke particles settle to the surface, or they fall to the surface with precipitation.
2 Warsaw would be cleaner and brighter without the power plant, and breathing cleaner air might help people be healthier. Yet the power plant provides electricity that the city needs.
3 Possible answers include walking and riding bicycles instead of using automobiles; conserving electricity, much of which comes from coal-burning power plants; and enacting policies that reduce air pollution. Businesses follow state or federal guidelines which require them to dispose of toxic materials properly and reduce toxic emissions.
Lesson 4 Focus on Content Air Quality Trends
Ask student volunteers to explain the meaning of the four lines on this graph. For each line, the graph plots percent change from 1970 to 2006. Vehicle miles traveled, energy consumption, and population all changed by a positive percentage, meaning their values increased. Air pollution changed by a negative percentage, meaning it declined.
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Teacher Guide continued