1. Aim: How does the planet Earth Support life?

2. I. Features of Earth that support life? A) Suitable atmosphere. B) Abundant usable water. C) Suitable range of temperatures.

3. II. Temperature A) Distance from the sun. B) Presence and composition of the atmosphere. 150 million kilometers

4. III. Atmosphere (atm) Nitrogen and Oxygen make up 99% of the. Gases in the atmosphere today: Page 1 ESRT

5. 1. Water Vapor: - source of all clouds and precipitation. - absorbs heat (from earth & sun) - makes the air lighter (less dense)

6. 2. Dust Particles: - helps to make clouds - any solid that can float in the air ( dust, salt, ash, organics) - In large quantities, these particles could block out the heat and light from the sun.

7. 3. Ozone: (O 3 ) - form of oxygen that bonds three oxygen atoms into one molecule of ozone. - filters harmful ultra-violet rays (u.v) from the sun. This gives you a sunburn. - depleted (destroyed) by CFC’s (chloroflorocarbons). These are found in aerosol cans and refrigerants.

8. IV. Human Influence on the Atmosphere: - Emissions from cars and factories account for nearly half the primary pollutants by weight.

9. Closure: With your partner, please complete the handout on “Changes in atmospheric composition” (#1-7) (Bottom bin)