2. Atmosphere The envelope of gases that surrounds the Earth Composed of:
Nitrogen (78%)
Oxygen (21%)
Carbon Dioxide (0.04%)
Water Vapor (0.5%)
Other Gases

3. Layers of the Atmosphere
The Earth’s atmosphere is divided into five basic layers:
Troposphere
Stratosphere
Mesosphere
Thermosphere
Exosphere

4. Air Pressure/Air Particles
Most of the air particles in the atmosphere can be found in the troposphere
Troposphere has high air pressure
Thermosphere has few air particles and very low air pressure

5. Temperature Changes
If Earth’s atmosphere is invisible, how can we divide it into different layers?
We divide the atmosphere into different layers based upon changes in temperature

6. Troposphere Layer closest to the Earth
Contains most of the air particles because gravity pulls them down
Only layer that has weather
Layer in which we live

7. Stratosphere 10-50 Km above the Earth
Contains the “Ozone Layer”- protects us from the sun’s UV rays
Airplanes prefer to fly here
Temperature rises slowly as you go higher

8. Mesopshere 50-85 Km Temperatures drop greatly in this layer
Coldest temperatures in the atmosphere
Contains a layer of charged particles called the “ionosphere”- This allows radio/tv signals to work

9. Thermosphere Over 85-300 Km above the Earth
Thinnest layer- particles very spread out
Temperatures rise as you go higher- hottest layer
Where the Northern Lights occur

10. Aurora Borealis (Northern Lights)

11. Exosphere Over 300 Km above Earth Beginning of outer space
Where satellites fly