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Chapter 22.1

Chapter 22.1. The Atmosphere http://www.history.com/video.do?name=The_Universe&bcpid=1398218663&bclid=19178662001&bctid=19203740001 http://www.history.com/video.do?name=The_Universe&bcpid=1398218663&bclid=19178662001&bctid=19192000001. Objectives:.

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Chapter 22.1

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  1. Chapter 22.1 The Atmospherehttp://www.history.com/video.do?name=The_Universe&bcpid=1398218663&bclid=19178662001&bctid=19203740001http://www.history.com/video.do?name=The_Universe&bcpid=1398218663&bclid=19178662001&bctid=19192000001

  2. Objectives: By the end of this section you WILL be able to… • Identify parts of Earth’s atmosphere • Explain where Earth’s atmosphere came from Key Terms: Troposphere, stratosphere, mesosphere, thermosphere, greenhouse effect

  3. Why SHOULD we care? • Severe weather involves changes in temperature and water content of the atmosphere. Understanding these relationships helps us predict the weather so that we can prepare for severe storms. • If it were not for the top layers of the atmosphere radio waves and cell phone waves would not travel as far as they do.

  4. Oxygen is not the only gas in the atmosphere • The two main gases are nitrogen, N2 (78%) and oxygen, O2 (21%) • The rest of the gases exist in small amounts and are known as trace gases • The layers of the atmosphere differ in temperature, density, and amounts of gases present

  5. Almost all weather occurs in the troposphere • The troposphere is the layer that is closest to Earth’s surface • The troposphere is the densest of the atmospheric layers

  6. Temperature changes with altitude • Lower portions of the troposphere are heated by the ground (insolation from the sun) • Since air at high altitudes is not close to the insolated surface it is colder • On average the temperature drops about 6 degrees Celsius every kilometer up • At the top of the troposphere the temperature stops decreasing

  7. Cool air can be trapped beneath warm air, this is known as temperature inversion • This is common in cities which happen to be located in basins (ie LA, Mexico City

  8. The stratosphere gets warmer with increasing altitude • The stratosphere is the layer above the troposphere • The temperature ranges from -67 degrees F to 32 degrees F • The stratosphere is about 31 miles thick • The stratosphere lacks water vapor, has few clouds and no storms

  9. The ozone layer is located in the stratosphere • Ozone or O3, absorbs solar radiation • O3 absorbs much of the ultraviolet radiation from the sun • So why is the ozone layer important?

  10. The mesosphere and thermosphere exhibit extreme temperatures • The mesosphere 31 miles – 50 miles the temperatures again drops • Near the top temperatures reach -112 F • At the next layer, the thermosphere 50- 298 miles, temperatures rise again up to 1796 F

  11. Refer to page 776 • The ionosphere occurs between the lower thermosphere and the upper mesosphere • Here, charged particles (known as ions) are formed from the absorption of solar radiation • These ions allow for radio waves to travel greater distances

  12. Colorful light displays known as auroras also occur in the ionosphere • This is caused when ions absorb energy from the sun and give off light in a small packet known as a photon SEE DEMO…

  13. Earth began to solidify around 4.4 billion years ago • Volcanoes began erupting and releasing gases, this process is known as outgassing • Several gases were emitted by the volcanoes but not O2

  14. Photosynthetic plants contributed the oxygen to our atmosphere roughly 2.5 billion years ago • Only about 350 million years ago did the oxygen levels reach that of present day • Animals produce carbon dioxide which plants need to make food and in turn O2 • This is known as a symbiotic relationship

  15. Humans can make chemicals that deplete the ozone layer • Chemicals known as CFC’s or chlorofluorocarbons were used as refrigerants and propulsions in aerosol cans • Why should we care?

  16. The greenhouse effect keeps Earth warm • Although it has gained a negative connotation in the past years • The greenhouse effect keeps us from freezing • One major greenhouse gas is simply water vapor

  17. Too much carbon dioxide may cause global warming • Global warming can cause the melting of polar icecaps and droughts • http://www.history.com/video.do?name=The_Universe&bcpid=1398218663&bclid=19178662001&bctid=19191814001

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