Earth

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• Earths First Atmosphere

1. NH3
2. CH4
3. H2O
How did the first atmosphere change into the
second atmosphere?

• Earths Second Atmosphere

1. N2
2. H2
3. CO2
4. H2O
How did the second atmosphere change into the
atmosphere we have today?
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Introduction to Weather

• I. Earths Atmosphere

A. Earth is divided into three areas.
1. Lithosphere -
Solid portion of the earth.
2. Hydrosphere -
Water portion of the earth.
3. Atmosphere -
Gas portion of the earth.

• II. Composition of the Earths Atmosphere

A. What is the earths atmosphere made of?
1. 78 Nitrogen
2. 21 Oxygen
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3. 1 - 4 Trace Elements
A.) Examples of trace elements are
H2O (Solid, Liquid or Gas), CO2, He, O3, Methane,
Dust and Salt.

• III Structure of the Earths Atmosphere

A. Earths Atmosphere has Five Layers
1. Troposphere
A.) Layer closest to the ground.
B.) Nicknamed the Weather Sphere.
C.) Most dense layer of the atmosphere. (
75 of the atmosphere)
D.) As you get higher in this layer temperature
decreases.
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2. Stratosphere
A.) 2nd layer of earths atmosphere.
B.) The ozone layer is part of this layer.
C.) Temperature increases, as you get higher due
to the ozone absorbing UV Radiation.
D.) The highest large passenger air crafts will
fly.
3. Mesosphere
A.) 3rd layer of the atmosphere.
B.) Most meteors burn up by the time they leave
this layer.
C.) As you get higher in this layer temperature
decreases.
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4. Thermosphere
A.) 4th layer of the atmosphere.
B.) T.V. Radio satellites revolve around earth
in this layer.
The ionosphere is a special part of the
atmosphere. It is not a separate layer, but part
of the thermosphere. Different regions of the
ionosphere make long distance radio communication
possible by reflecting the radio waves back to
Earth. It is also home to auroras. Temperatures
in the ionosphere just keep getting hotter as you
go up!
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• 5. Exosphere

A.) Outer most layer of the earths atmosphere.
B.) The space shuttle orbits earth in this layer
on most space missions.
C.) No clear boundary between this layer and
space.
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• IV. Earths Ozone Layer

A. What is Ozone?
1. Ozone is a form of oxygen.
2. One atom of oxygen is O, one molecule of
breathing oxygen is O2, and one molecule of ozone
is O3.
B. How does the ozone layer help earth?
1. Ozone absorbs most of the ultra violet
radiation that enters the earth.
2. Too much exposure to UV radiation can damage
most living things.
3. In mammals it WILL! cause CANCER!
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4. About 800,000 to 1,000,000 Americans develop
skin cancer every year.
5. About 10,000 Americans die every year from
skin cancer.
C. Is the Ozone Layer Thinning?
1. The ozone layer is thinning and in some areas
does not even exist.
2. The biggest hole is over Antarctica.
3. Chlorofluorocarbons or CFCs are being blamed
for thinning most of the ozone layer.
4. CFCs are made up of 3 Chlorine atoms, 1
Fluorine atom, and 1 Carbon atom.
5. CFCs are found in refrigerating systems,
aerosol cans, and Styrofoam packaging.
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D. How do CFCs affect the ozone layer?
1. One chlorine atom, from a CFC molecule, reacts
with one of the oxygen atoms, from an ozone
molecule.
2. That splits up the ozone molecule into a
chlorine oxygen compound and a breathing oxygen
molecule.
3. A free oxygen atom can break the bonds of the
chlorine oxygen compound. This forms a single
chlorine atom and a breathing oxygen molecule.
4. The chlorine atom then will attack another
ozone molecule, which will start the process all
over again.
5. If we would stop the production of CFCs right
now, it would take Earths atmosphere over 50
years to rid itself from CFCs.
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