1. The Atmosphere

2. What gases compose the Atmosphere?
Nitrogen (78%)
Oxygen (21%)
Carbon Dioxide, Helium, Argon, Water Vapors & other substances. (1%)

3. ~ Oxygen and carbon dioxide are the two most important gases in the atmosphere because they are used for photosynthesis and cellular respiration.

4. The three functions of the atmosphere are:
1. Protects living organisms from harmful UV radiation.
2. Warms the planet.
3. Supplies energy allowing photosynthesis.

5. The 5 layers of the atmosphere :
1.Troposphere
2.Stratosphere
3.Mesosphere
4.Thermosphere
5.Exosphere

6. The Troposphere is where most of the gases and our weather is found
The Troposphere is where most of the gases and our weather is found. The Stratosphere has our ozone shield. We live in the Troposphere. The Exosphere is the outer most layer of the atmosphere.
The higher the altitude, the less dense the atmosphere.

7. Climate
It is the average weather in an area over a long period of time.
Climate is affected by temperature, humidity, winds, and precipitation.

8. Weather Weather is due to the interactions of 4 elements.
1. Hydrogen - the sun
2. Atmosphere - transfer of heat or light
3. Shape and composition of Earth’s
surface- water vs. land
4. Waves - radiation

9. Ozone Form of oxygen with molecules made of 3 oxygen atoms.
The ozone shield protects us from harmful radiation because it absorbs most of the ultraviolet light from the sun.

10. Ozone Eaters - CFC’s Chlorofluorocarbons
3 sources of CFC’s are refrigerators, air conditioners and styrofoam.
CFC’s are harmful because they destroy the ozone.
It is estimated that one chlorine atom can destroy as many as 100,000 ozone molecules.

11. Effects of ozone depletion and increased UV radiation
1. Cause mutations or death of cells near the surface of the body. (skin cancer)
2. Kill one-celled organisms that live near the surface of the ocean disrupting ocean food chains and reducing harvests.
3. Reduction of producers would further increase the amount of carbon dioxide in the atmosphere.
4. Weaken the immune system, making the body more susceptible to diseases.
5. Increases the chances for cataracts and therefore blurred vision or blindness.

12. The Greenhouse Effect
The atmosphere is like a greenhouse. Sunlight heats the Earth, and as the heat rises, some escapes into space, but the rest is trapped by gases in the troposphere and warms the air.

13. Greenhouse Gases Gases that trap and radiate heat.
Examples: water vapor, CO2, CFC’s,
methane, nitrous oxides.

14. Greenhouse Gases
Water Vapor is the most abundant greenhouse gas!!!

15. The most important greenhouse gases are water vapor and carbon dioxide.
Carbon Dioxide levels are increasing due to deforestation and the burning of fossil fuels.
Due to an overall increase in greenhouse gases, the average temperature of the Earth is increasing which is known as global warming.

16. Global Warming
May cause oceans to absorb more heat energy making hurricanes and typhoons more common and more devastating.
Ocean currents may also change which will affect the Earth’s weather.
May also cause icebergs, glaciers, and the polar caps to melt causing a rise in sea level. This could also cover some coastal areas.