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23.1 Characteristics of the
Atmosphere
Composition of the Atmosphere
• What is the most abundant gas in
the atmosphere???
• NITROGEN
• Another gas that is not shown in
the graph is water vapor.
• Water vapor fluctuates due to
evaporation, transpiration, and
condensation.
Journal:
What do you know about ozone?
Ozone in the Atmosphere
O3, Ozone
• Absorbs harmful
ultraviolet radiation
• Ultraviolet Radiation
is harmful because it
causes damage to our
cells (UV A and UV B)
Destruction of the Ozone Layer
• Compounds called Chlorofluorocarbons, CFCs,
and nitrogen oxide break down ozone.
Journal:
• What are the possible effects of continued
breakdown of the ozone layer? (support your
response by explaining why you think this
might happen)
Oxygen in the Atmosphere
Nitrogen in the Atmosphere
Atmospheric Pressure
• Pressure air = Force air / surface area
• Gravity pulls the gasses of the atmosphere
toward the Earth’s surface
Measuring Atmospheric Pressure
• Barometer: measures atmospheric pressure
– Mercurial Barometer:
atmospheric pressure
presses down on liquid
mercury raising the
mercury in a tube.
Measuring Atmospheric Pressure
• Barometer: measures atmospheric pressure
– Aneroid Barometer:
atmospheric pressure
causes a vacuum sealed
chamber to collapse under
atmospheric pressure.
Changes are indicated by a pointer
Layers of the atmosphere
Does temperature change in the
layers of the atmosphere?
How does temperature change with each layer?
Layers of the Atmosphere
• Layers of the atmosphere
are identified based on
temperature differences
Layers of the Atmosphere
• Troposphere: Closest to
earth’s surface
– Where all weather
changes occur
– Temp. decreases with
increasing altitude
Layers of the Atmosphere
• Stratosphere: Extends
from the Troposphere to
50 km
– Temperature increases
with increasing altitude
– The ozone layer is found
here
– Stratopause: upper
boundary with the highest
temperature
Layers of the Atmosphere
• Mesosphere: From 50 km
to 80 km above earth’s
surface
– Temperature decreases
with increasing altitude
– Coldest layer of the
atmosphere
Layers of the Atmosphere
• Thermosphere: From 80
km
– Temperature increases with
increasing altitude
– Nitrogen and oxygen absorb
solar energy
– Ionosphere: 80km – 550km,
reflect radio waves
– Exosphere: above 550 km,
blends into space
Air Pollution
• Air Pollutants: substances in the air that are
harmful to plants, animals, water systems,
ozone layer
– Examples: Sulfur dioxide, carbon monoxide, lead,
hydrocarbons
• What is the source of air pollutants?
– Burning of fossil fuels
The Effects of Air Pollution
• Acid Precipitation
The Effects of Air Pollution
• Temperature Inversions
Layers of the atmosphere activity.