The composition of Earth’s Atmosphere and the role of the atmosphere in Earth’s weather and climate

*Earth’s Atmosphere

Mrs. Radef

Science 7

Spring 2015

(Adapted from CCSD RPDP Content Benchmark E.8.A.4 http://www.rpdp.net/sciencetips_v3/E8A4.htm )

*The

Atmosphere

*Solar Energy

*Earth’s

Magnetic

Fields

Life on Earth is Supported by:

The Atmosphere*Absorbs the energy from the Sun

*Recycles water and other chemicals to provide a moderate climate *Protects us from high-energy radiation and the frigid vacuum of space

The Atmosphere*Earth’s atmosphere is a very thin layer of gases that surround a very large planet.

*An analogy of the relative diameter of the Earth compared to the thickness of the atmosphere would be to exhale onto a billiard ball (from a pool table).

*The billiard ball represents the Earth and the thin layer of condensation represents the relative thickness of its atmosphere.

*The atmosphere makes up less than one millionth of the total mass of the Earth.

*Two gases make up the bulk of the atmosphere:

*nitrogen (N2) at 78%

*oxygen (O2) at 21%,

*The other one percent includes water vapor, carbon dioxide (CO2), argon, and trace amounts of other gases.

The Atmosphere

Constant components(proportions remain the same over time and location)Nitrogen (N2) 78.08%Oxygen (O2) 20.95%

Argon (Ar) 0.93%

Neon, Helium, Krypton 0.00%

*The atoms and molecules that make up the various layers in the atmosphere are constantly moving in random directions.

*When they strike a surface they exert a force on that surface in what we observe as pressure.

Pressure and the Atmosphere

*Atmospheric pressure can be imagined as the weight of the overlying column of air.

*Pressure decreases exponentially with increased altitude.

Pressure and the Atmosphere

*At the top of Mt. Everest (elevation 29,028 ft.), pressure is as low as 300 mb.

*There are approximately one-third as many gas molecules inhaled per breath on top of Mt. Everest as at sea level

*Climbers experience severe shortness of breath the higher they go, as less oxygen is inhaled with every breath.

Pressure and the Atmosphere

Earth’s atmosphere is divided into four layers:

*Troposphere

*Stratosphere

*Mesosphere

*Thermosphere 

Layers of the Atmosphere

*Variable components have a much greater influence on both short-term weather and long-term climate.

*Variations in water vapor impact relative humidity.

*CO2, CH4, N2O, and SO2 absorb heat emitted by the Earth and thus warm the atmosphere, creating the greenhouse effect.

Earth’s Changing Atmosphere

Earth’s Changing Atmosphere

Variable components(amounts vary over time and location)

Carbon dioxide (CO2) 0.04%

Water vapor (H20) 0-4%

Methane (CH4) trace

Sulfur dioxide (SO2) trace

Ozone (O3) trace

Nitrogen oxides (NO, NO2) trace

Earth’s Changing Atmosphere

Where can you go to learn more about the Earth’s Atmosphere?*http://www.noaa.gov/

*http://www.nasa.gov/

*http://earthguide.ucsd.edu/earthguide/diagrams/atmosphere/index.html

*http://www.ucar.edu/learn/1_3_1.htm

Thanks for Watching