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ATMOSPHERE UNIT
Chapter 15
The Atmosphere
Chapter 15.1
Characteristics
of the Atmosphere
• Atmosphere: the mixture of gases
that surrounds the Earth.
– contains oxygen needed for
respiration
– protects living things from the sun’s
harmful rays
– keeps Earth warm
– transport energy to different regions
of the planet
Atmospheric Pressure
• Air Pressure: the measure of the
force with which the air molecules
push on a surface
– Changes throughout the atmosphere
• Altitude: the height of an object
above the Earth’s surface
• Inverse relationship between Altitude
& Air pressure
Altitude
Air pressure
Atmospheric Pressure
• Why?
– Less air above you to weigh down on
you, remember air is made of
particles.
– Air becomes less dense as you travel
upward.
• Less molecules in the same amount
of space means less pressure.
Atmospheric Pressure
14.7 lbs per square inch! That is 10-20 tons!
• Why do your ears pop in airplanes?
Question submitted by: Pan Field Your ears pop in air planes because the air high above the
surface of Earth is less dense than air near the surface, because air near the surface has all
the air above it pushing down.
Some air planes can fly so high they require oxygen masks or a pressurized cabin, so the pilot
and passengers don’t pass out for lack of air. Even higher and air planes can’t fly because
their wings require air to provide lift.
As you ascend in an airplane and the air pressure decreases, the air trapped in your inner ear
will cause your eardrums to push outward. This expansion causes not only the discomfort
you feel before your ears "pop," but also a decrease in hearing ability, because the pressure
on your ears drums makes the sound harder to transmit.
Your body can equalize the pressure between your inner ear and the atmosphere by allowing
some air from your inner ear to escape through the Eustachian tubes, two small channels
that connect the inner ears to the throat, one on each side.
When they open, you feel the pressure release and you hear the change because it’s happening
in your ear. This equalization of pressure is the "pop."
On the way down from an air plane flight, the air pressure increases, while your inner ear is still
at the lower pressure it has adjusted to. Now, the extra pressure pushes the eardrums
inward.
Eventually, the pressure will equalize again, but many people don’t wait, they just hold their nose
closed, close their mouth and blow. Because the air from their lungs has nowhere to go, it is
forced into the inner ear through the Eustachian tubes, "popping" their ears.
This effect can happen to people driving through the mountainous areas or riding elevators in
tall buildings, but it is more noticeable on airplanes because the altitude changes quickly
and they fly higher than buildings or mountains.
T. McWilliams and Dr. J. Bass contributed to this report
• No “top” to atmosphere
– About 500 km (300 miles) up is
considered “outer space”
• 99% of atmosphere is in the
bottom 30 km (20 miles).
•
Composition of the
Atmosphere Today
Gases
– Nitrogen: 78%
– Oxygen: 21%
– Argon, carbon dioxide & other: 1%
– (water vapor amounts vary)
• Solids
– Ex. dust, dirt, smoke, volcanic ash
• Liquids
– Most common: water (in the clouds)
Gases in the
Atmosphere Today
Nitrogen
78%
Oxygen
21%
Other
1%
Oxygen
Nitrogen
Other
Earth’s Early Atmosphere
•
•
•
•
•
•
Water Vapor: 79%
Carbon Dioxide: 11 – 12%
Sulfur Dioxide: 6%
Nitrogen: 1%
Other gases: 1 %
Changed due to photosynthesis
Gases in the Early
Atmosphere
Water Vapor
80%
Carbon Dioxide
Sulfur Dioxide
Water Vapor
Nitrogen
other
Sulfur Dioxide
6%
Carbon Dioxide
11.5%
other
1%
Nitrogen
1%
Atmosphere from space
Natural Cycles That
Affect the Atmosphere
• Carbon Cycle
1. Plants take in CO2 to use for
photosynthesis
2. Plants give off O2 during
cellular respiration
(using energy from the sun to make food)
3. Animals take in O2 and give
off CO2
• Nitrogen Cycle
1.Organisms (nitrogen fixing bacteria)
in the soil take N2 from the air
2.Organisms gain nitrogen by eating
plants
3.Decaying organisms release nitrogen
to soil
4.Bacteria in soil releases N2 back into
the air
• Water Cycle
1. H2O evaporates from oceans,
lakes, ponds, etc.
2. Plants and animals give off H2O
3. As the temperature in the
atmosphere cools the water
condenses and forms clouds
4. Liquid H2O falls from the
atmosphere as rain or snow
(precipitation)
Sudden Changes That
Affect the Atmosphere
• Volcanic Eruptions
– Gases and ash can affect the weather
and climate worldwide by blocking
sunlight and lowering temperatures.
• Forest fires
• Dust storms
The Atmosphere
Chapter 15.2
Heating of the Atmosphere
• The Sun is our principle energy
source.
– 2 things can happen to energy from
the sun:
• 30% is reflected by clouds,
atmosphere & surface
• 20% is absorbed by clouds,
atmosphere
• 50% is absorbed at the surface by
oceans, land & living things
Radiation and the Atmosphere
Heating of the Atmosphere
• Radiation: the transfer of energy
as electromagnetic waves.
Not all of the radiation reaches the
earth’s surface.
Radiation absorbed by the land,
water & atmosphere is changed
into thermal energy.
Heating the Earth & Atmosphere
1. Radiation – EM waves from the sun
moves energy through space to the
Earth.
2. Conduction: the transfer of thermal
energy from one material to another by
direct contact.
–
–
Thermal energy always moves from warm
to cold.
When air molecules come into direct
contact with a warm surface, they heat up.
Heating the Earth & Atmosphere
3. Convection: the transfer of thermal
energy by the circulation or movement
of a liquid or gas.
–
–
Most thermal energy in the atmosphere
moves this way
Remember: warm air is LESS dense than
cool air, so. . .
Warm air rises and
cold air sinks
Convection Currents
Air is cooled as it goes higher into
the atmosphere. As air cools
it becomes more dense.
As the Cool air sinks, it
pushes the warm air up
Warm air rises
Air becomes less dense
as it is warmed at the
surface of the earth.
Radiation, Convection &
Conduction
Aurora
Borealis
“Northern
Lights”
Aurora Australis
“Southern Lights”
The Atmosphere
Chapter 15.3
EM Radiation Review
•
Ultraviolet radiation
– Radiation of higher frequencies
(more energy) than visible light,
which can cause sunburn, skin
cancer and other types of damage.
•
Infrared radiation
– Radiation of lower frequencies (less
energy) than visible light. Detected
as heat.
• Using a tanning bed more than 10 times a year
made people 7 times more likely to develop
malignant melanoma
• The risk of melanoma was increased by 300%
for those using tanning beds occasionally and
by 800% for those using tanning beds more
than 10 times a year.
• about 38,000 people will be diagnosed with
melanoma this year in the U.S. and 7,300
people will die from this condition.
• The United States Department of Health &
Human Services names UV radiation from the
sun, and from artificial sources such as
tanning beds and sun lamps, as a proven
carcinogen - a cancer causing substance[!
Ozone Layer
• Ozone: a molecule that is made up of
three oxygen atoms (O3).
• Ozone Layer is located in the
Stratosphere.
– Absorbs ultraviolet radiation while
allowing other radiation to pass through
(transmit)
– Protects life on Earth from ultraviolet
radiation
Ozone Layer
Ozone Layer
Ozone Layer Depletion
• Ozone attacked by Chlorofluorocarbons
(CFCs)
CFCs are compounds made up of chlorine,
fluorine and carbon bound together.
extremely stable molecules, CFCs do not
react easily with other chemicals in the
lower atmosphere- stay around long time.
 CFCs produced for cooling systems, spray
cans and foam for packaging
Ozone Layer Depletion
Ozone Depletion
The Green house Effect
• Greenhouse Effect: Earth’s natural
heating process by which gases in
the atmosphere trap thermal energy
and keep it from escaping into
space.
– Acts like a “blanket” so the earth stays
warmer
– Greenhouse Gases: Carbon dioxide,
Methane, Ozone (on the ground) &
water vapor
The Green House Effect
Radiation Balance
• Radiation balance: the balance between
incoming energy (from the sun) and
outgoing energy (returned to space).
• Must be equal for Earth to remain
livable.
• Global warming: a rise in average
global temperature.
– Large debate over connection to greenhouse effect and long term implications.
Atmosphere
15.4
• Human activities affect the
atmosphere
Air pollution
• Smoke and other harmful materials
added to the air
– May be added by humans or natural
processes
– Classified as either gases or
particulates
Air pollution
• Fossil fuel burning is major source
of pollution in cities and suburbs
– Releases gases and particulates
– Unburned fuels
– Smog = sunlight + car exhaust
•
•
•
•
•
According to the American Lung
Association 2015 Rankings
The 10 Most Polluted American Cities by
Short-Term Particle Pollution:
1) Fresno-Madera, CA
2) Bakersfield, CA
3) Visalia-Porterville-Hanford, CA
4) Modesto-Merced, CA
5) Las Angeles-Long Beach, CA
6) San Jose-San Francisco-Oakland, CA
7) Salt Lake City-Provo=Orem, UT
8) Logan, UT
9) Fairbanks, AK
10) Pittsburgh-New Castle-Weirton, PAOH-WV
The 10 Most Polluted American Cities by
Year-Round Particle Pollution:
1) Fresno-Madera, CA
2) Bakersfield, CA
3) Visalia/Porterville/Hanford, CA
4) Modesto/Merced, CA
5) Las Angeles/Long Beach, CA
6) El Centro, CA
7) San Jose/San Francisco/Oakland, CA
8) Cinisinnati/Wilmington/Maysville,
OH/KY/IN
9) Pittsburgh/New Castle/ Weirton,
PA/OH/WV
10) Cleveland,/Akron/Canton, Ohio
• The 10 Most Polluted
American Cities by Ozone:
• 1) Los Angeles/Long Beach,
CA
2) Visalia /Porterville
/Hanford, CA
• 3) Bakersfield, CA
4) Fresno/Madera, CA
5) Sacramento/Roseville, CA
• 6) Houston/ The Woodlands,
TX
7) Dallas-Fort Worth, TX
8) Modesto/Merced, CA
• 9) Las Vegas/Henderson,
NV/AZ
10) Phoenix/Mesa/Scottsdale,
AZ
Effects of Pollution
• Air pollution causes health effects
– Irritate eyes, nose, throat, lungs
– May smell bad
– Over time may develop lung disease
– Extra problem for asthma patients
– Particulates stick to surfaces, damage
plants or structures, reflect sunlight
Greenhouse gases
• Greenhouse gases produced naturally
– regulate Earth’s temperature, make livable
• Human activities release greenhouse
gases faster than natural processes can
remove from the environment
– CO2 from burning fossil fuels
– Methane from cattle and rice fields
– Nitrous oxide from fertilizers
Global Warming
• Scientists concerned additional
greenhouse gases may lead to warming
– not clear how additional gases and
temperature increase are linked
• Concentration of greenhouse gases in
atmosphere, particularly CO2 , has been
shown to increase since 1950 to 2013
– From 315 ppm to over 400 ppm
Temperature Change
Electrical Energy Produced By Fossil Fuel Combustion
(Billion
Kilowatthours)
Fossil Fuel
G8 Nation
Total
Combustion
Canada
136.31
622.98
France
44.65
532.57
Germany
340.38
567.33
Italy
286.35
201.7
Japan
759.93
1031.22
Russia
668.26
996.82
United Kingdom
244.5
342.48
United States
2,788.87
4,100.14
%
21.9%
8.4%
60.0%
70.4%
73.7%
67.0%
71.4%
68.0%
U.S. Carbon Dioxide Emissions
1990-2014
Reducing Greenhouse Gases
• Global warming is a global problem
• Largest contributor to gases - U.S.
• New technologies to reduce:
-equipment that uses less energy
(energy star, hybrid, organic)
-produce energy without fossil fuels