Atmosphere Test Study Guide
Name: ___________________________
Period: ____
1. Define the following terms:
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Atmospheric pressure: the force of the air weighing down over a unit of area.
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Density: the amount of mass in a given volume of substance.
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Humidity: the amount of water vapor in the air.
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Relative humidity: the percentage of water vapor in the air compared to the amount of
water vapor that the air can hold at a specific temperature.
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Weather: the physical condition of the atmosphere at a specific place at a specific time.
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Climate: the type of weather that is common to an area.
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Meteorology: the study of the atmosphere, including weather.
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Air mass: a large section of the lower troposphere that has the same weather
throughout.
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Front: the place where two air masses with different densities meet.
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Barometer: the instrument that is used to measure air pressure.
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Dew Point: the temperature at which condensation occurs.
2. What is the percentage of each of these gases in the atmosphere?
Nitrogen: 78%
Oxygen: 21%
Argon: 0.93%
Carbon dioxide: 0.04%
3. How does air pressure change with altitude (elevation)?
As attitude increases, air pressure decreases.
4. What kind of weather is associated with low pressure?
Clouds, storms, warm air
5. What kind of weather is associated with high pressure?
Cold, clear skies
6. What are the five layers of the atmosphere from earth to space?
Troposphere  Stratosphere  Mesosphere  Thermosphere  Exosphere
Atmosphere Test Study Guide
Name: ___________________________
Period: ____
7. How does temperature change with altitude in each of the layers of the atmosphere?
First layer: Tropoosphere
As altitude increases, Temperature decreases
Second layer: Stratosphere
As altitude increases, Temperature increases
Third (middle) layer: Mesosphere
As altitude increases, Temperature decreases
Fourth layer: Thermosphere
As altitude increases, Temperature increases
Fifth layer: Exosphere
8. Describe each aspect of the water cycle below:
Evaporation: The process in which sunlight adds energy to the water so that it changes from a
liquid to a gas.
Transpiration: The process in which leaves release water through pores called stomata.
Condensation: The process in which water vapor reaches its dew point temperature, becomes
saturated and condenses to form clouds.
Precipitation: Any form of water vapor falling from the clouds, including rain, snow, sleet, and
hail.
9. Describe how each of the following fronts occurs. Also, draw the weather map symbol for
each front.
Cold Front: the leading edge of a cooler mass of air, replacing at ground level a warmer mass
of air.
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Cooler, denser air wedges under the less dense, warmer air and lifts it.
The upward motion causes lowered pressure along the cold front.
Can cause the formation of a narrow line of showers and thunderstorms when enough
moisture is present.
On weather maps, the surface position of the cold front is marked with the symbol of a
blue line of triangles/spikes pointing in the direction the cold front is traveling.
Atmosphere Test Study Guide
Name: ___________________________
Period: ____
Warm Front: occurs when a warm air mass slides over a cold air mass.
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Relatively stable
Moves slower than a warm front
Long transition from cold air to warm air (warm air moves slowly)
Temperature gradually rises
Clouds and precipitation (lighter rain that lasts longer)
Red line with semi-circles in the direction of warm front movement
Occluded Front: occurs when a cool front catches up with a warm front.
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Made of 3 air masses, in order from front to back, are cold, warm, and then cold again.
Causes a drop in temperature
Fierce weather at the occlusion (precipitation and shifting winds are typical)
Weather map: purple line with alternating triangles and half circles in the same
direction.
Stationary Front: occurs when air masses are stopped by a barrier, such as a mountain range,
or when they are stopped by each other.
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May bring days of rain, drizzle, and fog.
Weather map = alternating blue triangles pointing in the direction of the cold front and
red semi-circles point in the direction of the warm front (opposite directions).
10. How does convection transfer heat in the atmosphere?
Warm air expands and becomes less dense, it is lighter. This lighter, warmer air then rises. As it
rises it begins to cool off. When the air cools, it contracts, and becomes denser. Denser air is
heavier and sinks toward the ground where it is then heated. This cycle of warm air rising and
cool air sinking is convection in the atmosphere.
11. Describe how local winds change between an island and the ocean during the day and at
night…where does the wind blow, and why? (Tip: Think about convection!)
During the day, the land heats up faster than the water, because water has a higher specific
heat (it takes more energy to change the temperature of water). The air over land is warmer,
Atmosphere Test Study Guide
Name: ___________________________
Period: ____
so it expands, gets lighter, and rises up. This creates an area of low pressure over land, because
the air is “lighter” and rises. During the day the air over the water is colder, so it contracts and
sinks, creating an area of high pressure. Wind blows from areas of high pressure to low
pressure, so during the day the cool ocean breeze blows toward the land. At night, this trend
reverses because the land loses the heat more quickly than the water does. Remember, the
sun is no longer shining at night. The water holds onto its thermal energy (it’s a good insulator)
and so the air over the water is warmer than the air over land. Warm air expands and becomes
“lighter” creating an area of low pressure. The cold air over land sinks and creates an area of
high pressure. High pressure flows to low pressure, creating wind, and the wind blows from the
land out to sea at night.
12. What is the jet stream, where is it located, and what does it do?
The jet stream is a narrow zone of very strong winds located in the middle latitudes of the
upper troposphere. It moves or blocks stormy weather (low pressure cells).
13. What is the Gulf Stream, where is it located, and what does it do?
The Gulf Stream is a warm surface ocean current that carries warm water from the equator up
the North Atlantic Ocean. The coastal cities that are affected by the Gulf Stream will then be
warmer and wetter as a result of the movement of this warm water.
14. What are the characteristics of Cirrus clouds and what kind of weather are they related to?
Cirrus clouds are thin and feathery, and they are associated with fair weather. However, if the
cirrus clouds become dense, then that is a sign that stormy weather is coming. Cirrus clouds are
found at high altitudes and the water vapor inside has frozen into ice crystals.
15. What are the characteristics of Cumulus clouds and what kind of weather are they related
to? Cumulus clouds are large, puffy, and white (“cotton balls floating the sky”) and they are
associated with fair weather. If the cumulus clouds gets bigger/taller (takes in more water
vapor), then it becomes a cumulonimbus cloud that brings thunderstorms. Cumulus clouds are
at lower altitudes.
Atmosphere Test Study Guide
Name: ___________________________
Period: ____
16. What are the characteristics of Stratus clouds and what kind of weather are they related
to? Stratus clouds are thin and sheet-like clouds found at low altitudes. They are associated
with fog and drizzle.
17. What are the characteristics of each of the following types of storms?
Thunderstorms = brief, intense electrical storms that affect a small area.
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Produced rapidly when air rising causes cumulus clouds to build upward into a
thunderhead.
Cloud type = cumulonimbus
Characterized by lightning and thunder, strong winds, heavy rain and sometimes snow,
hail or no precipitation at all.
Can cause flooding, hail, or tornadoes
Hurricanes = huge, rotating storms that form over the ocean near the equator.
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Strong winds, heavy rains, and large, powerful waves.
Can cause flooding, hail, or tornadoes
Tornadoes = violently whirling wind sometimes visible as a funnel-shaped cloud.
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Produced from severe thunderstorms
Spiraling high winds
Extremely low pressure
Winter storms are associated with quickly moving cold fronts; includes blizzards and ice storms.
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High winds
Very low temperatures
Large accumulations of snow
18. How does the Coriolis Effect influence wind direction in the Northern and Southern
Hemispheres?
The Coriolis Effect influences wind direction. In the Northern Hemisphere, it causes winds to
curve to its right. In the Southern hemisphere, it causes winds to curve to its left.