Aim: How does the Atmosphere on Earth support life Aim: How does the Atmosphere on Earth support life? Do Now: In your notes, describe what you think the atmosphere does for us?

I. Atmosphere (atm) Composition Made up of 4 layers (troposphere, stratosphere, mesosphere and thermosphere) - nitrogen and Oxygen make up 99% of the gases in the atmosphere today Page 1 ESRT

most important gas in the atmosphere oceans are the source What source of water vapor in the atmosphere? A. Water Vapor: most important gas in the atmosphere oceans are the source absorbs heat (from earth & sun) makes the air lighter (less dense) Altitude (km) ESRT p.14 Describe the relationship seen in the graph.

- any solid that can float in the air ( dust, salt, ash, organics) B. Dust Particles: - any solid that can float in the air ( dust, salt, ash, organics) - helps make clouds - In large quantities, these particles could block out the heat and light from the sun. What might be an effect of blocking out light and heat from the sun? Has this happened before? Mt. St. Helens Eruption, 1980

Mt. St. Helens Eruption Washington, 1980 Mt. Eyjafjallajökull Eruption Iceland, 2010

C. Ozone: (O3) - found in the stratosphere. - poisonous to people. - filters harmful ultra-violet rays (UV) from the sun. - depleted (destroyed) by CFC’s (chloroflorocarbons). These are found in aerosol cans and refrigerants.

DO NOT COPY Someone said there is a hole in the Ozone Each winter as temperatures drop, ozone over southern pole is “thinned” rapidly and severely. This depleted region is known as the “ozone hole”. As temperatures begin to warm up, the ozone begins to build up once again. Ozone measurement for September 2013 Ozone measurement for March 30th 2014 DO NOT COPY

Where does the other half come from? II. Human Influence on the Atmosphere: - Emissions from cars and factories account for nearly half the pollutants by weight in the atmosphere. Where does the other half come from?

III. Atmosphere and Temperature - Perfect distance from the sun! - Water vapor and CO2 in the atmosphere traps heat and keeps our planet warm. 150 million kilometers

Closure: In your notes, answer the following questions; How can humans decrease their negative influence on the atmosphere? Are there positive influences that people have on the atmosphere?