1. The Earth’s…

2. The planet earth has a mixture of gases surrounding it called the atmosphere.

3. Composition of the Atmosphere Nitrogen (N 2 ) 78% of the Earth’s atmosphere Is the most abundant gas. Oxygen (O 2 ) Takes up about 21% of the atmosphere Pollutants & other Gases Make up about 1% of the earths atmosphere

4. Earth's atmosphere has a unique composition of gases when compared to that of the other planets in the solar system

5. Nitrogen Cycle –N 2 cycles through the atmosphere with the nitrogen cycle. –It is removed from the atmosphere with bacteria & lightening –Nitrogen is taken up by plants to utilize growth and development (fertilizer)

6. Oxygen Cycle –Oxygen also cycles in the atmosphere. –Living organisms are used as food sources and oxygen is used by most organisms that digest other organisms. –Chemical weathering of rocks can cause oxides to form. –Oxygen is released into the atmosphere by plants through the process of photosynthesis

7. Regions of the Atmosphere The atmosphere consists of definite layers or strata.

8. Troposphere Layer immediately surrounding the earth (on average 12 km about the surface) Most of the “weather” occurs here Jet stream is located here Temperature decreases with altitude.

9. The top of the troposphere is the TROPOPAUSE. “___pause” means the temperature stays constant in this region.

10. Stratosphere Layer just above the tropopause The ozone layer is found here, which protects the earth from ultraviolet rays (UV Rays) Temperature increases with altitude The top layer of the stratosphere is called the STRATOPAUSE. Again, temperature is constant.

11. Mesosphere Meteors from space often enter the mesosphere, however burn up due to air friction before reaching the bottom. Temperature increases with altitude. The upper layer is the mesopause

12. Thermosphere Above the Mesosphere Temperatures are extremely high, could be over 2000 degrees!

13. Ionosphere The lower part of thermosphere Contains ions which reflect radio waves The ions also help create aurora borealis or “northern lights”

14. Exosphere The outer most layers of the atmosphere Its limits are not precisely known After the exosphere is space……

15. ThankYou (unless you were talking during my presentation… and not being respectful of all my hard work!)