U3L2 - The Atmosphere

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Science Fusion PowerNotes - Grade 8
Unit 3 Lesson 2 - The Atmosphere

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U3L2 - The Atmosphere

  1. 1. Unit 3 Lesson 2 The Atmosphere Copyright © Houghton Mifflin Harcourt Publishing Company
  2. 2. Unit 3 Lesson 2 The Atmosphere Indiana Standards Copyright © Houghton Mifflin Harcourt Publishing Company • 8.2.1 Recognize and demonstrate how the sun’s energy drives convection in the atmosphere and in bodies of water, which results in ocean currents and weather patterns. • 8.2.4 Describe the physical and chemical composition of the atmosphere at different elevations.
  3. 3. Up and Away! Copyright © Houghton Mifflin Harcourt Publishing Company What is Earth’s atmosphere? • The atmosphere is the mixture of gases that surrounds Earth. • The functions of the atmosphere include protection from the sun, maintaining temperature, and supplying gases necessary for breathing. Unit 3 Lesson 2 The Atmosphere
  4. 4. What is Earth’s atmosphere? • The atmosphere is made of 78 percent nitrogen gas, 21 percent oxygen gas, and 1 percent other gases. • The atmosphere also contains small particles of dust, volcanic ash, sea salt, smoke, skin, bacteria, and pollen. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  5. 5. What is Earth’s atmosphere? • In the atmosphere, water is found in the clouds as liquid droplets and solid water in the form of snow and ice crystals. • Most water in the air is in the form of water vapor. Water vapor is an invisible gas. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  6. 6. How do pressure and temperature change in the atmosphere? • Gravity pulls gas molecules in the atmosphere toward Earth, causing pressure. • Air pressure is the measure of the force with which air molecules push on a surface. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  7. 7. How do pressure and temperature change in the atmosphere? • As altitude, or distance from Earth’s surface, increases, air pressure decreases. • As altitude increases, temperatures change. • Some parts of the atmosphere are warmer because of gases that absorb solar energy. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  8. 8. Look Way Up Copyright © Houghton Mifflin Harcourt Publishing Company What are the layers of the atmosphere? • The atmosphere is divided into four layers based on temperature and other properties. • The thermosphere is the uppermost layer with temperatures that increase as altitude increases. • The thermosphere feels cold because particles are so far apart. Unit 3 Lesson 2 The Atmosphere
  9. 9. What are the layers of the atmosphere? • The mesosphere is between the thermosphere and stratosphere. • Temperatures decrease as altitude increases. • Meteoroids begin to burn up in the mesosphere. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  10. 10. What are the layers of the atmosphere? • The stratosphere is between the mesosphere and troposphere. • Temperatures generally increase as altitude increases. • Ozone in the stratosphere absorbs ultraviolet radiation from the sun, which warms the air. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  11. 11. What are the layers of the atmosphere? • The troposphere is the lowest layer of the atmosphere. • Temperature generally decreases as altitude increases. Temperatures near the surface vary greatly. • The troposphere contains 80 percent of the atmosphere’s total mass. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  12. 12. What are the layers of the atmosphere? How do temperatures differ with altitude in the atmosphere? Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  13. 13. Here Comes the Sun … Copyright © Houghton Mifflin Harcourt Publishing Company How does the atmosphere protect life on Earth? • Earth’s atmosphere reflects or absorbs most of the radiation from the sun. • The ozone layer is in the stratosphere and contains a high concentration of ozone. It absorbs most of the solar radiation. Unit 3 Lesson 2 The Atmosphere
  14. 14. How does the atmosphere protect life on Earth? • Ozone-layer thickness changes by season and location. • Scientists have discovered a steady decrease in the overall volume of ozone over time. • Ozone can also be destroyed by certain chemicals in the air. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  15. 15. How does the atmosphere protect life on Earth? • The greenhouse effect is the process by which gases in the atmosphere absorb and radiate energy as heat back to Earth. • Shortwave radiation from the sun reaches Earth’s surface and reradiates back into the atmosphere, where it is trapped by greenhouse gases. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere
  16. 16. How does the atmosphere protect life on Earth? • How is the heat inside of a closed car in the summer similar to the greenhouse effect? Copyright © Houghton Mifflin Harcourt Publishing Company Unit 3 Lesson 2 The Atmosphere

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