1. Earth’s Atmosphere Chapter 1: Section 1

2. Importance of the Atmosphere Earth’s atmosphere is a thin layer of air that forms a protective covering around the planet. If Earth had no atmosphere, then days would be extremely hot and nights would be extremely cold.

3. Importance of the Atmosphere Earth’s atmosphere maintains a balance between the amount of heat absorbed from the Sun and the amount of heat that escapes back into space. Heat absorbed from Sun Heat escaped from Earth Atmosphere

4. Importance of the Atmosphere Earth’s atmosphere also protects us from the Sun’s harmful rays.

5. Makeup of the Atmosphere Earth’s atmosphere is a mixture of gases, solids, and liquids that surrounds the planet. It extends from Earth’s surface into outer space. Gases – Nitrogen (78%), Oxygen (21%), Other Gases (1%) Solids – Dust (wind picks up from ground), Salt (ocean spray), Pollen (plants) Liquid Droplets (water and volcanic materials)

6. Layers of the Atmosphere There are five layers of the atmosphere. The lower layers include the troposphere and stratosphere. The upper atmospheric layers include the mesosphere, thermosphere, and exosphere.

7. The Lower Layers - Troposphere We live within the troposphere. It is the lowest layer of the atmosphere. It contains 99% of the water vapor and 75% of the atmospheric gases. Rain, snow, and clouds occur in the troposphere.

8. The Lower Layers - Stratosphere The stratosphere extends from about 10km above the Earth’s surface to 50 km. Contains the ozone layer, which protects us from the Sun’s harmful rays.

9. The Upper Layers - Mesosphere Extends from the top of the stratosphere to 85km above Earth. Shooting stars are meteors in the mesosphere. The frigid temperatures in the upper mesosphere create noctilucent clouds – clouds of ice crystals.

10. The Upper Layers - Thermosphere Named for its high temperatures. It’s the thickest atmospheric layer and is found between 85km and 500km above Earth’s surface. Auroras occur in the thermosphere.

11. The Upper Layers - Ionosphere Within the mesosphere and thermosphere is a layer of electronically charged particles called the ionosphere. It allows radio waves to travel across the country to another city.

12. The Upper Layers - Exosphere The outer most layer of the atmosphere. Space shuttles and satellites orbit the Earth in the exosphere.

14. Gravity

15. Temperature in Atmospheric Layers

17. The Ozone Layer

18. Ozone Destruction