CHAPTER 17 READING GUIDE
ATMOSPHERE
17.1 The Atmosphere in Balance
Causes
Volcanic Eruptions
Effect on Atmosphere
Lowered temperature
Volcanic eruptions
Released gases to form Earth’s Atmosphere
Increasing altitude
Lowers water-vapor concentration
Atmospheric recycling
Atmosphere’s composition remains stable
Fossil fuel burning
Increasing CO2 in the atmosphere
The composition of the atmosphere is 78% Nitrogen, 21% Oxygen, 1% Argon, and less
than .5% carbon dioxide. It also contains tiny particles of rock, dirt, pollen, salt crystals,
and soot.
The atmosphere stays stable because substances such as oxygen, carbon dioxide, and
water move out of the system at the same rate at which they entered the system.
Photosynthesis, decomposition of organic materials, evaporation, precipitation, and
animal exhalation are ways that materials move in and out of the system.
17.2 Heat and the Atmosphere
Thermosphere
Height above Earth’s
Surface
90+ kilometers
Mesophere
50-90 kilometers
Stratosphere
16 - 50 kilometers
Troposphere
Up to 16 Kilometers
Key Factors affecting
temperature
Thin atmosphere absorbs a
lot of radiation, leading to
very high temperatures.
Decreased ozone leads to
cold temperatures; altitude
leads to decreases
Ozone absorbs ultraviolet
rays, leads to increases.
Sun’s radiation absorbed by
Earth’s surface creates heat;
altitude leads to decreases
Radiation, conduction, and convection move heat energy through the atmosphere as
follows: radiation: ultraviolet rays cause the transfer of heat from the sun to your skin.
conduction: a fire’s warmth spreading to your body comes from conduction of heat from
the fire to the air and then from the air to your body. convection: when a building’s upper
floors are hotter than the lower ones, convection had made the hot air raise and cool air
fall.
3. Explain why it is important to keep the Earth’s heat budget balanced. Tell how
greenhouse effect helps maintain this balance: When Earth’s heat budget is balanced, its
temperature remains relatively constant. If the budget becomes unbalanced, Earth’s
average temperatures would rise or fall depending on the direction of the imbalance. The
greenhouse effect captures solar radiation that would otherwise disperse back into space.
17.3 Local Temperature Variations
1.
2.
3.
4.
Factors Affecting Temperature at Given Location
Intensity of Insolation
Type of Surface
Time of Day
1. Land
Time of Year
2. Water
Latitude
Cloud cover
2. Explain how one of the factors you listed in the organizer above affects the
temperature at a given location.
Time of Day: affects the angle of the sun’s rays, with the most direct rays falling at noon
and building heat into the afternoon.
Latitude: affects the angle of the sun’s rays by placing some parts of Earth closer to the
sun than others.
Time of Year: affects how close Earth is to the sun, again affecting the angle of the sun’s
rays. Cloud cover reflects insolation back into space, decreasing the temperature on
Earth.
Land: Land heats up faster and cools down faster than water, which allows for high
temps during the day and cooler temps at night, as well as temp fluctuations from day to
day.
Water: Water takes longer to heat up and cool down. Water temperature does not vary at
a fast rate of time.
17.4 Human Impact on the Atmosphere
Air Pollution
Acid Rain
Global Warming
Smog
1. Can cause
1. unstable
1.
health
and severe
problems.
weather
2. Destruction of
and
2.
monuments
temperature
and other items
.
2. melting of
the polar
ice cap
resulting in
rising sea
levels.
3. Crop
problems.
Health
problems/illne
sses
reduced crop
yields on
farms.
Ozone Depletion
1. Health
problems/illne
sses
2. death of
marine life.
3. Crop
problems.