1. The Atmosphere

2. What is the atmosphere?
The atmosphere is a mixture of gases that surround the earth.
It holds the oxygen you breathe and protects you from the sun’s radiation.
It also helps keep us warm.

3. How does it work?

4. Composition 78% nitrogen (N) 21% oxygen (O) 1% small particles of
dust, ash, sea salt,
dirt, and smoke

5. Water
Water can be found in the atmosphere as:
Liquid
Solid
Gas

6. Air Pressure
Air pressure is the measure of the force that air molecules push against a surface.
Air pressure is strongest at the surface because there is more air above you.
As altitude increases,
air pressure decreases.
This is because air is
less dense the higher up you go.

7. Atmosphere and Temperature
Air temperature changes with altitude.
Temperature differences mainly result from the way solar energy is absorbed.
Some gases absorb energy better than others.

8. Altitude, Temperature, and Pressure

9. Layers of the Atmosphere
Thermosphere
Mesosphere
Stratosphere
Troposphere

10. Names and Their Meaning
Sphere = Ball
Tropo = turning or change
Gasses turn and mix
Strato = layer
Gasses are layered
Meso = middle
Middle layer
Thermo = heat
Temperature is highest

12. Troposphere: Where We Live
Densest layer – makes up 90% of the atmosphere’s mass
Contains almost all carbon dioxide, water vapor, weather, and life
Temps vary greatly

13. Stratosphere: Home of the Ozone
Temperature rises as altitude rises in this layer because ozone absorbs heat from radiation.
Ozone protects the troposphere from harmful ultraviolet radiation.

14. Mesosphere: Middle Layer
Middle and coldest layer
Temp decreases as altitude increases

15. Thermosphere: The Edge
Temp increases with altitude
Heat is a transfer of thermal energy, but the atoms are so far apart in the thermosphere that no heat is transferred.
Although the temperature may be high, it is not hot.

16. Ionosphere
The Ionosphere is in the upper mesosphere, lower thermosphere.
Particles get heated by radiation and become electrically charged.
Charged particles are called ions.
These particles sometimes radiate energy in the form of light called auroras.

22. Exosphere Just past the thermosphere is the exosphere.
Very few molecules. The outer most layer.

24. Review Why does temperature vary from one layer to another?
Why does air pressure decrease as altitude increases?
Why does the thermosphere have high temperatures but does not feel hot?
What two gasses make up most of the atmosphere?
What are the layers of the atmosphere, in order from bottom to top?