1. Atmospheric Pressure and LayersOr
What can a human pyramid teach you about atmospheric pressure?

3. COMPOSITION OF THE ATMOSPHERE
78% Nitrogen
21 % oxygen
1% everything else

4. Pressure
Air pressure (atmospheric) is caused by the weight of the air pushing down on you.
So, pressure is greatest lower in the atmosphere since more air is above you
Picture a human pyramid, the persons on the bottom have the most pressure on them, and those above have less.

5. Temperature varies with altitude
The temperature varies according to how much UV is absorbed in the layer
Temperature is greatest in the Thermosphere then decreases to its lowest temperature in the mesosphere

6. Thermosphere Hottest layer (1,700 degrees C)
The outer edge of the thermosphere is called the exosphere (sometimes referred to as separate layer)
Ionosphere is in lower part Reflects AM radio waves
The ions will show at certain times closer to the poles and are called the northern lights (aurora borealis) or southern lights (aurora australius)

7. Mesosphere 3rd layer. “meso” means middle
Coldest layer temp. decreases as you go up.
Part of the ionosphere is in the upper part

8. Stratosphere 2nd layer up, strato means layered
thin contains little moisture
Temperature increases as you go up because the ozone layer is at the top.
The ozone layer protects the Earth from UV
ozone

9. The Troposphere Tropo means changing
Temperature decreases as altitude increases
The lowest and densest layer of the atmosphere
Most weather occurs here. Most water vapor, carbon dioxide, air pollution, and life are here.