Composition of the atmosphere accounts for much of the difference between Earth and other planets
The atmosphere is crucial for life on Earth because it supplies oxygen, water, CO2 and a few nutrients (N) to living organisms and protects living organisms from temperature extremes and excessive UV radiation
Layers of the atmosphere
Troposphere
Stratosphere
Mesosphere
Thermosphere
Exosphere
Temperature variations within the atmosphere
Due to the way different energy is absorbed as it moves downward through the atmosphere
The Earth's surface is the primary absorber of solar energy
As altitude (distance from sea level) increases
Atmospheric pressure decreases
Atmospheric gases extend many kilometers above Earth's surface
As Earth's gravity pulls the gases toward its surface
The weight of those gases presses down on the air below
People find it difficult to breathe high mountains because fewer molecules of air exist there
The Sun is the source of most of the energy on Earth
Before solar energy reaches the atmosphere
It must withstand the atmosphere
Because some layers contain gases that easily absorb the Sun's energy while other layers don't
The different layers have different temperatures
Molecules that compose air within the troposphere
Are warmed mostly by heat from the Earth's surface
Molecules of ozone within the stratosphere
Absorb some of the Sun's energy, raising the temperature
Because more ozone molecules are found at higher altitudes in the stratosphere, the temperature increases with increasing altitude
Atmosphere
Atmospheric gases extend many kilometers above Earth's surface
Earth's gravity pulls the gases toward its surface
Molecules nearer Earth's surface are closer together
Dense air exerts more force than less dense air near the highest of the atmosphere
People find it difficult to breathe high mountains because fewer molecules of air exist there
Sun
Source of most of the energy on Earth
Energy from the Sun reaching Earth
1. Must withstand the atmosphere
2. Some layers contain gases that easily absorb the Sun's energy
3. Other layers don't
4. Assorted layers have different temperatures
Troposphere
Lowest layer of Earth's atmosphere
Starts at the surface and goes up to 7-20 km
All weather occurs within this layer
Contains water vapor and dust particles
Temperature decreases at 1°C per 165 m of height
Stratosphere
Second layer of the atmosphere, extends up to 50 km
Extremely dry, contains little vapor
Absorbs UV rays and protects Earth from harmful radiation
Temperatures increase with altitude due to ozone
Stratopause separates Stratosphere and Mesosphere
Mesosphere
Found above the Stratosphere
Coldest part of the atmosphere, temperatures drop below -80°C
Meteors dissipate in this layer
Mesopause separates Mesosphere and Thermosphere
Thermosphere
Layer above Mesopause, from 80 to 400 km
Average temperature is 980°C
Radio waves transmitted from Earth are reflected by this layer
Temperature increases with height
Aurora and satellites occur in this layer
Exosphere
Outermost layer of the atmosphere
Zone where molecules and atoms escape into space
Extends from top of Thermosphere up to 10,000 km
Temperature generally decreases with altitude in the troposphere because gases in this place absorb very little of the incoming solar radiation
Ozone layer is located in the stratosphere which absorbs the sun's ultraviolet radiation
As distance from Earth (altitude) increases, air pressure decreases
People find it difficult to breathe in high mountains because fewer molecules of air exist there
Temperature is the basis for dividing the atmosphere into different layers
CFCs are air pollutants that are destroying the ozone layer
As a student, ways to protect the atmosphere and prevent ozone damage include...</b> (student response)