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Earth’s atmosphere

Learn about the composition and importance of Earth's atmosphere, how it affects us through air pressure variations, and the five main layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

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Earth’s atmosphere

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Presentation Transcript

  1. Earth’s atmosphere The envelope of gases that surround the planet.

  2. Atmosphere • Composition of the atmosphere: Top three gases: Nitrogen 78% Oxygen 21% Other gases 1% Add to that Carbon Dioxide, Water vapor and particles (dust, smoke)

  3. Importance of the atmosphere • Makes conditions suitable for living – air, temperature • Protects us from UV (ultraviolet) radiation • Protects us from meteors/ objects from space

  4. How does atmosphere affect us? • Air has mass, therefore the weight of the atmosphere exerts a force on surfaces. Air pressure is the result of the column of air pushing down on an area. The column of air extends upward through the entire atmosphere.

  5. How does atmosphere affect us? • Air pressure can vary at different places. At the top of a mountain, air pressure is less than at sea level. Air pressure decreases as altitude increases. Sea-level air has the weight of the whole atmosphere pressing on it. So air pressure is greater at sea level. Air near the top of the atmosphere has less weight pressing on it, and thus has lower air pressure.

  6. Layers of the ocean & atmosphere • In the ocean, the 3 layers changed in temperature and pressure….the deeper you went, the lower the temperature & higher the pressure. How do you think the layers will change in the atmosphere?

  7. Layers of the Atmosphere

  8. Essential Question How does the atmosphere change with altitude?

  9. There are 5 Main Layers of the Atmosphere • They are divided according to changes in temperature!! • Changes in gases and air pressure also occur.

  10. The Troposphere • 0-12 km – Lowest layer (7.5 miles) • Nearly all weather (rain, snow) occurs here! – including clouds • Warmest part of the troposphere is closest to earth’s surface.

  11. The Stratosphere • 12- 50 km (up to 30 miles) • The OZONE LAYER is here. Protects us from UV Rays. • The temperature remains about - 60°C.

  12. The Mesosphere • Means “middle sphere” • Extends from stratosphere • The Coldest Layer: drops to about -100°C! • Comets and meteor burn up here before hitting the Earth.

  13. The Thermosphere • Means “heat sphere” – hottest layer (can reach up to 2000°C) but the air is thin - less dense, so it would feel cold. • Extends out to ~ 700km • Known as the upper atmosphere • Has Aurora Borealis

  14. Thermosphere

  15. Aurora Borealis

  16. The Exosphere • Transition zone between earth’s atmosphere and space: has no outer limit but it blends into space- • Satellites orbit here.

  17. Review • 1. The layers of the atmosphere are classified according to changes in what? • 2. What are the 5 main layers of the atmosphere? • 3. Where does the aurora borealis occur? temperature Troposphere, stratosphere, mesosphere, thermosphere and exosphere Thermosphere

  18. http://www.srh.noaa.gov/jetstream//atmos/layers.htm

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