1. Warm Up What is the atmosphere?

2. Why is the ATMOSPHERE important?

3. What is it?  What is the atmosphere and how have we discovered more about it?  Video Clip

4. Weather  Weather is the condition of the earth’s atmosphere at a particular time and place  So what is the atmosphere?

5. Earth’s Atmosphere  A thin layer of gases that surrounds the planet  Makes conditions on earth suitable for living things

6. Composition  Nitrogen – 78%  Oxygen – 21%  Carbon dioxide  Water vapor  Other gases  Particles of liquids and solids

7. Nitrogen  Most abundant gas in the atmosphere  78% of the air we breathe N2N2N2N2  Essential to living things – needed to grow and repair body cells  Bacteria convert nitrogen from the air and then plants use it to create proteins that people and animals need.

8. Oxygen  Second most abundant gas in the air  Only 21% of the volume  Usually in the form of O 2  Plants and animals use it  Important in other processes  Ozone (O 3 ) – forms when lightning interacts with Oxygen

9. Carbon Dioxide  CO 2  Only in small amounts -.036%  Essential to life – plants need it to make food

10. Other Gases  Called trace gases because only small amounts are present

11. Water Vapor  Amount in the air varies from place to place  Plays an important role in the earth’s weather  Clouds, precipitation

12. Particles  Pure air is only gases, but this exists only in a lab  In the real world, there are many different particles –Dust –Smoke –Salt –Other chemicals