1. A mixture of gases that surrounds a planet
The Atmosphere
A mixture of gases that surrounds a planet

2. Why do we need our atmosphere??

3. Protects us from damaging solar rays

4. Protects us from some meteor strikes

5. Provides the oxygen we need to breathe

6. Acts like a blanket at night and keeps the heat in so our planet doesn’t freeze

7. Image from ISS

9. The atmosphere is a mixture of gases that surrounds the Earth.
Composition
Nitrogen 78% Oxygen 21% Other 1%
All other gases and particles (water vapor, CO2 (carbon dioxide) dust particles, salt, Argon, etc.)

12. Air Pressure depends on how much air is above you
Air Pressure depends on how much air is above you. It is measured as the force that air molecules push on a surface.
Air has weight
The lower in the atmosphere you are, the higher the air pressure
The higher in the atmosphere, the lower the air pressure

13. High Altitude =
Lower Pressure
Low Altitude =
Higher Pressure

14. Air Temperature-changes with height.
Higher Altitude = Lower Temperature
Lower Altitude = Higher Temperature
As you go up a mountain temperature decreases at a constant rate (About 6.5o C F) per kilometer)

16. Thermosphere (ionosphere) Exosphere
The Atmosphere Layers
(from the ground up!)
Troposphere
Stratosphere
Mesosphere
Thermosphere (ionosphere)
Exosphere

19. End of the characteristics of the atmosphere

20. The Troposphere Height From the surface to about 16 km (5 to 8 miles)
Temperature
Temperatures decrease with altitude in the Troposphere
Facts:
Where we live
All weather occurs in this layer
Clouds are here-planes fly
99% of the Earth’s water vapor
Densest Layer so Air Pressure is highest at this layer
Contains 90% of the atmosphere’s total mass!

22. The Stratosphere Height: This layer extends from 16 to 50 km
Temperature:
Temperature increases with altitude (height)
Facts:
Thin layer of air that does not mix
Jet airplanes fly in this layer
Abundant amounts of Ozone is found in this layer (O3)
Ozone absorbs harmful ultraviolet (UV) radiation from the sun
Warms the air in this layer
This ozone protects living organisms in the Troposphere

23. Troposphere – yellow layer
Stratosphere – white layer

24. The Mesosphere Height: This layer extends from 50 to 90 km
Temperature:
Coldest layer
Temperature decreases with altitude
-93oC at the top
Facts:
The middle layer of the atmosphere
Shooting stars burn up in this layer

25. Troposphere – Orange layer
Stratosphere – white layer
Mesosphere – light blue layer

26. The Thermosphere Height: Extends from 90 to 300 km Temperature
Temperature increases with altitude
This is the hottest layer! Temperatures at the top can reach 1000oC (but you’ll freeze if you go out without a jacket!!)
Air molecules carry the heat, but they are very far apart so odds one of them hitting you and giving off heat to you is very unlikely!
Facts:
Upper most Layer
Space Shuttle and satellites orbits in this layer

28. (part of Thermosphere)
The Ionosphere
(part of Thermosphere)
Northern and Southern Lights (auroras)
Electrically Charged gas particles called ions
Harmful Solar Radiation is absorbed here too.
Reflects AM radio waves

29. The Exosphere Height: Extends from 300 to 600 km
Temperature: Density of the air is too thin for molecules to act like a gas and colliding with each other so too hard to measure temperature
Facts:
Where our atmosphere thins out and merges with space
Lowest air pressure is found at this layer.
Many satellites orbit in this layer