Atmosphere

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Atmosphere
The atmosphere is a thin layer that forms a
protective covering around the planet.
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How Does the Atmosphere Protect?
Moderation of surface Temperatures The
atmosphere limits the amount of heat absorbed
from the Sun and released back into space. If the
Earth had no atmosphere, daytime temperatures
would be 250 F and nighttime would plunge to -
200 F.
The Atmosphere Blocks Dangerous Radiation
Radiation, harmful to life, is blocked by the
atmosphere. This includes gamma rays, x rays, and
ultraviolet rays.
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What is the Atmosphere?

• Mixture of gases, solids, and liquids
• Extends from the Earths surface to outer space.

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Why does the Earth have an Atmosphere?
Volcanoes Formed the Earths First Atmosphere
Just after the Earth formed, the Earth had no
atmosphere. Volcanic eruptions produced the
Earths first atmosphere.
Earths Early Atmosphere Four billion years ago
the Earths atmosphere contained water vapor,
carbon dioxide, methane, and nitrogen, but NO
free oxygen.
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Blue-Green Algae Mounds
Oxygen in the Atmosphere About 3.5 billion
years ago, blue-green algae, one of the earliest
life forms on Earth, produced the first
atmospheric oxygen as a waste product of
photosynthesis.
Photosynthesis
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• Nitrogen is produced in volcanic eruptions
  accumulates.
• Methane decomposes in the presence of oxygen.
• Hydrogen Helium escaped into space.
• CO2 has been incorporated into carbonate rocks.
• Oxygen continues to be produced as a plant waste
  product.

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What is the composition of Earths Atmosphere?

• Nitrogen is the most abundant gas in the
  atmosphere
• Oxygen is the next most abundant.
• CO2 is only 0.04.
• Percentages do not vary around the Earth!

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What is the only substance that exists as a
solid, liquid, and gas in the Earths atmosphere?
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Why isnt water vapor included in the composition?
because the amount varies considerablynearly
none to almost 4!
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The Makeup of the Modern Atmosphere
Solids in the Atmosphere The atmosphere also
contains small solid particles such as dust, ice,
and salt.
Ground Dust Ground dust is picked up by the wind.
Volcanic Dust Volcanic dust can remain in the
atmosphere for years.
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Smoke Soot from Fires This is an image of the
Lower North Forth Fire in Conifer, CO, March 2012
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The Makeup of the Modern Atmosphere
Ice Crystals This halo around the Moon is caused
by ice crystals.
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Salt The atmosphere contains salt from the
ocean spray.
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Pollutants

• Nitrogen Oxides Brown cloud/smog
• Ozone O3 (Normal oxygen is 02)
• Natural and beneficial in upper atmosphere
• Part of brown cloud/smog in lower atmosphere
• Sulfur Dioxide Acid rain