1. Earth’s Atmosphere
5/20/14

2. Composition 78% Nitrogen (N2) 21% Oxygen (O2)
Released when living things decay and volcanoes erupt
21% Oxygen (O2)
Produced by plants and some protists during photosynthesis
1% Various Atmospheric Gases
Water vapor
Carbon Dioxide
Solid particles such as dirt, dust, and ash are carried in air

3. Atmospheric Pressure Atmosphere is held in place by Earth’s gravity
Gravity pulls on gas molecules
Air pressure
Stronger near surface
Weaker the further away
Altitude Air Pressure

4. Atmospheric Temperature
Air temperature changes as you increase altitude
Sections of warmer and colder temperatures
Temperature changes based on how solar energy is absorbed
Type of gases affect solar absorption

5. Layers of Atmosphere Divided into four layers based on temperature
Troposphere
Stratosphere
Mesosphere
Thermosphere
“-sphere”  each layer surrounds the Earth like a hollow ball

6. Troposphere Lowest layer of the atmosphere Densest of the four layers
We live here
Densest of the four layers
90% of atmosphere’s total mass
Layer in which weather occurs
Extends to 6-7 miles (~33,000 ft) above Earth’s surface

7. Stratosphere Located above the troposphere
Air is very thin and contains little moisture
Few clouds exist here
Contains the Ozone Layer (O3)
Protects from UV rays
Ranges from 7-31 miles above the Earth’s surface

8. Mesosphere Located above the stratosphere
Coldest layer of the atmosphere
As low as -90oC (-130oF)
Difficult to study layer
Weather balloons and aircraft cannot reach layer
Extends from miles above Earth’s surface
Mesospheric Clouds

9. International Space Station
Thermosphere
Uppermost atmospheric layer
Warmest layer of the atmosphere
As high as 1,700oC (3,100oF)
Influenced by solar radiation
Contains the Ionosphere and Aurora borealis
Electrically charged particles
Extends from (or 621) miles above Earth’s surface
International Space Station