Chapter 22 Section 1
Review Page 554 (1-8)
1. Describe the
composition of dry air at
sea level.
• Nitrogen = 78%
• Oxygen = 21%
• Argon = 0.9%
• Other gases (like CO2 < 0.1%
Gases in the Atmosphere
2. Identify five main
components of the
atmosphere.
• Nitrogen
• Oxygen
• Water Vapor
• Ozone
• Particulates
Particulates
3. Explain the cause of
atmospheric pressure.
• Atmospheric pressure is caused by
the weight of atmospheric gases as a
result of gravity pulling the gas
molecules toward Earth.
Atmospheric Pressure
4. Explain how the two
types of barometers
measure atmospheric
pressure.
• Mercurial Barometer: Atmospheric
pressure pushes on the well at the
base of the barometer. This holds
the level of the mercury in the tube
at a height indicating the air
pressure.
Mercury Barometer
Mercury Barometer
4. Explain how the two
types of barometers
measure atmospheric
pressure.
• Aneroid Barometer: Atmospheric
pressure pushes in on the side of a
sealed metal container causing the
sides of the container to bulge in or
out, moving the pointer on a scale
showing the air pressure.
Aneroid Barometer
5. Identify the layer of
the atmosphere in which
weather occurs.
• Weather happens in the troposphere.
Weather
in the
Troposphere
6. Compare the four main
layers of the atmosphere.
• Troposphere: lowest layer, weather
happens here, highest pressure
• Stratosphere: second layer, contains the
ozone layer, gets warmer as you go up
• Mesosphere: coldest layer, meteors burn
up here, gets colder as you go up
• Thermosphere: hottest layer, ionosphere is
here so auroras happen here, hottest
layer, lowest air pressure (near zero)
Layers of the Atmosphere
7. Identify the two
atmospheric layers that
contain air as warm as
250 C?
• The troposphere and the
thermosphere
Temperature Ranges of Layers
25o C
25o C
Thermosphere
Troposphere
8. Why is atmospheric pressure
generally lower beneath a
mass of warm air than beneath
a mass of cold air?
• Molecules move farther apart
when they are heated, so there
are fewer particles in a given
area to exert pressure.
Cause of Atmospheric Pressure
The End…..