Our Atmosphere

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Our Atmosphere
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Composition of the Atmosphere

• Most abundant elements in the atmosphere are
  nitrogen, oxygen and argon
• The two most abundant compounds are carbon
  dioxide and water vapor

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• 78 of Earths atmosphere is composed of nitrogen
• 21 of Earths atmosphere is composed of oxygen

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• In addition to containing gases, the atmosphere
  contains various tiny solid particles, called
  particulates.
• Examples volcanic dust, ash, microscopic
  organisms, pollen, etc

Sea spray evaporates leaving salt behind
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Atmospheric Pressure

• Gravity holds the gases of the atmosphere
  (including O3, which we breathe) near Earths
  surface.
• The air molecules are compressed together and
  exert force on Earths surface.

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Atmospheric Pressure (cont)

• 99 of Earths atmosphere is closer to the
  surface. While the remaining 1 extends upward
  for hundreds of kilometers but gets thinner at
  higher altitudes.
• Atmospheric pressure and oxygen levels decrease
  as altitude decreases. Meaning the higher you go,
  the less pressure and gases there will be.

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Exosphere
Layers of the Atmosphere
Ionosphere
Thermosphere
Mesosphere
Stratosphere
Troposphere
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Earths atmosphere is divided into four main
layers.

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere

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Troposphere

• Weather occurs here
• Holds almost all of the mass of the atmosphere
• Lowest layer of atmosphere
• As altitude increases, the temperature decreases
• At its top, the temperature stops decreasing and
  stays at about -60C feathery clouds of ice form
  here

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Stratosphere

• Second layer
• Contains the ozone layer
• From top of the troposphere, it extends 50 km
  above Earths surface
• The upper stratosphere is warmer than the lower
  stratosphere. Why?

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Because

• The middle portion of the stratosphere has a
  layer of air where there is much more ozone than
  in the rest of the atmosphere. When the ozone
  absorbs energy from the sun, the energy is
  converted into heat, warming the air.

How does the ozone layer benefit the Earth?
It protects life from the suns ultraviolet
radiation.
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Colonel Joe W. Kittinger
August 16, 1960
Fell at 714 mph!! Thats more than the speed of
sound!!
Sound travels at 660mph
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What level of the atmosphere was he in?

• Kittinger jumped from an altitude of more than
  31km!

?
Stratosphere !!!
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Mesosphere

• Middle layer
• Outer mesosphere temperatures approach -90C.
• Protects Earths surface from being hit by most
  meteoroids
• What you see as a shooting star, or meteor, is
  the trail of hot, glowing gases the meteoroid
  leaves behind here.

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Thermosphere

• outermost layer
• air is very thin
• very hot, up to 1,800C (sunlight strikes the
  thermosphere first and Nitrogen and Oxygen
  molecules convert this energy into heat.)
• divided into two layers
• Ionosphere
• Exosphere

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Thermosphere Sub-layers

• Ionosphere Energy from the sun causes gas
  molecules in the ionosphere to become
  electrically charged particles called ions.
  Important in radio transmissions.

Aurora Borealis seen from Alaska. Particles from
the sun enter the ionosphere near the poles.
These particles strike atoms in the ionosphere,
causing them to glow.
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Thermosphere Sub-layers

• Exosphere outer portion of the thermosphere
  satellites are used for phone calls and
  television.

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Ok, so what are the four main layers of the
atmosphere?(Begin with the layer closest to the
Earth)

• Troposphere
• Stratosphere
• Mesosphere
• Thermosphere

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The two sub-layers of the Thermosphere are

• Ionosphere
• Exosphere

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So, whos who?

• outermost layer has two sub-layers
• middle layer, protects from meteoroids
• important in radio transmissions ions
• first layer, weather occurs here
• Satellites orbit here, important in phone calls
  and television
• ozone is present planes fly here

• Mesosphere
• Troposphere
• Ionosphere
• Thermosphere
• Stratosphere
• Exosphere

• d , 2. a , 3. c
• 4. b , 5. f , 6. e