Download AGS General Science Chapt 16

14. The
is important because it absorbs most
of the harmful ultraviolet radiation from the sun.
A troposphere
C mesosphere
B ozone layer
D ionosphere
15. Fluffy, white clouds are called _
__.
A cirrus clouds
C cumulus clouds
B stratus clouds
D rain clouds
16. Unequal heating of the earth's surface by the sun
causes
.
A formation of cumulus clouds
B wind
C rain
D condensation of water vapor
17. A continuous cycle of rising warm air and falling cold
air is called
.
A water vapor
C the nitrogen cycle
B a thunderstorm
D a wind cell
18. The prevailing westerlies are
.
A winds coming from the west
B the wind belts nearest the equator
C trade winds
D winds blowing to the west
Critical Thinking
Write the answer to each of the following questions.
19. When a rain forest is destroyed, how does this affect the
composition of the atmosphere?
20. Moist air is pushed up a mountainside, as shown. How
might the weather on the right side of the mountain be
different from that on the left side?
Do not wait until the night before a test to study. Plan your
study time so that you can get a good night's sleep before a test.
The Earth's Atmosphere
Chapter 15
349
Chapter
Weather and
Climate
W
eather takes many different forms. One form of
severe weather begins as a tropical storm over an
ocean. As the storm gains energy, it becomes a
spinning hurricane. The center, or eye, of a hurricane is
surrounded by swirling white masses of clouds. In Chapter 16,
you will learn about different weather conditions and how they
are measured. You also will explore weather patterns and
climate zones.
Organize Your Thoughts
Weather conditions
Data collection
Air temperature
Air pressure
Humidity
Wind speed
Wind direction
Precipitation
Weather patterns
and maps
Air masses
Fronts
Highs and lows
Storms
Climate zones
Goals for Learning
To describe weather conditions
To identify instruments that measure weather
conditions
To explain how fronts, highs, and lows affect weather
To read a weather map
To describe various kinds of storms
To describe the earth's major climates
350
Weather Conditions and Measurements
Objectives
After reading this
lesson, you should
be able to
+ explain what
weather is.
• describe how
temperature is
measured.
+ define air pressure
and humidity.
+ tell how wind
speed, wind
direction, and
precipitation
are measured.
Weather
State of the atmosphere
at a given time ami
place
Look out the window. Is it a cloudy day? Is it windy? Cloudy
and windy refer to conditions of the atmosphere. Weather is
the state of the atmosphere at a given time and place.
The weather is always changing because conditions in the
atmosphere are always changing. A meteorologist measures
these conditions, looks for patterns, and uses this information
to predict the weather.
Air Temperature
One of the first weather conditions you hear on a weather report
is the temperature of the air. Air temperature is measured with
a thermometer. Most thermometers are made of a thin tube
filled with colored alcohol. Meat causes a liquid to expand, or
take up more space. So when the air gets warmer, the liquid in
the thermometer expands and moves up the tube. If the air gets
cooler, the liquid contracts, or takes up less space. Then the
liquid moves down the tube.
The unit of measure for temperature is the degree (°). Two scales
for measuring temperature are shown in the diagram. People
in the United States usually use the Fahrenheit scale. People in
most other countries use the Celsius scale. All scientists use the
Celsius scale. Compare the common temperatures shown on
both scales.
Fahrenheit scale
Celsius scale
(Q)
Water boils
212 F
Body temperature
98.6 F
37 C
Room temperature
68CF -
|20°C
Water freezes
32 F-
O'-'C
Weather and Climate
Chapter !(•>
351
Air pressure
Force of air against
a unit of area
Barometer
Instrument used to
measure air pressure
Air Pressure
Think about what happens when you blow air into a balloon.
The balloon gets bigger because the air particles push against
the inside wall of the balloon. The push, or force, of air against
an area is called air pressure.
Air in the atmosphere exerts pressure, too. The air above you
and around you constantly pushes against your body. You don't
feel this pressure because air in your body pushes out with the
same amount of force. But what happens if air pressure suddenly
changes? For example, while riding upward in an elevator, you
may have felt your ears "p°P-" Your ears pop because they are
adjusting to a drop in air pressure. As you move higher in the
atmosphere, there is less air present to push on you, so air
pressure drops.
Air pressure is measured with an instrument called a barometer.
Two kinds of barometers are shown here. In a mercury barometer,
air pushes down on a dish of mercury, forcing the mercury to
rise in a tube. In an aneroid barometer, air pushes on a short
metal can. A pointer connected to the can shows the amount of
air pressure. Aneroid barometers are lightweight and portable.
Air
pressure
Air
pressure
76 centimeters
(about 30 inches)
Mercury
Mercury barometer
352
Unit 2
litirth Science
Aneroid barometer
Humidity
Amount of water vapor
in the air
Relative
humidity
Amount of water vapor
in the air compared to
the maximum amount
of water vapor the air
can hold
Psychrometer
Instrument used to
measure relative
humidity
Different scales are used to measure air pressure. Most weather
reports give the air pressure in inches. Air pressure usually ranges
from 29 to 31 inches (74 to 79 centimeters), which is the height
of mercury in a mercury barometer.
A change in air pressure indicates a change in weather. A rise in
air pressure usually means drier weather is on the way. A drop
in air pressure often means precipitation is coming.
Humidity
Have you ever described a hot day as sticky or muggy? Such
days are uncomfortable because of high humidity. Humidity
is the amount of water vapor in the air. When the air contains
a lot of water vapor, the humidity is high. The maximum
amount of water vapor that the air can hold, or its capacity,
depends on the air temperature. Warmer air can hold more
water vapor than colder air can.
The amount of water vapor in the air compared to its capacity
is called relative humidity. It is calculated as a percent. A
relative humidity of 50 percent means that the air contains half,
or 50 percent, of its water vapor capacity. When the air is
completely filled w i t h water vapor and cannol hold more, the
relative humidity is 100 percent.
A psychrometer is an instrument used to measure relative
humidity. It is actually made up of two thermometers. The
bulb of one thermometer is covered with a damp cloth. As
water evaporates from the cloth, it cools. The temperature
of this thermometer is lower than the temperature of the dry
thermometer. The lower the humidity, the faster the water
evaporates and the lower the temperature drops. The relative
humidity is then found by comparing the temperatures of the
two thermometers to a special chart.
Weather and Climate
Chapter 16
353
Anemometer
Instrument used to
measure wind speed
Wind vane
Instrument used to find
wind direction
Wind Speed and Direction
The speed of the wind is an important weather condition. It
helps meteorologists predict how fast an approaching storm
will arrive. Wind speed is measured with an anemometer. An
anemometer has three or four arms, with a cup attached to the
end of each arm. These cups catch the wind and cause the arms
to rotate. When the wind speed increases, the arms rotate faster.
This spinning rate may be indicated on a dial or digital display.
The photo below shows a simple anemometer with three arms. It
also shows another important weather instrument: a wind vane.
A wind vane shows the direction from which the wind is
blowing. It is often shaped like an arrow. Wind hits the larger
back section of the vane. The vane turns so that it points into
the wind.
Wind is named by the direction from which it comes. A wind
that moves from north to south is called a north wind. A north
wind causes a wind vane to point north.
A quick glance at this anemometer and wind vane
will tell you both wind speed and direction.
354
Unit 2
Earth Science
Rain gauge
Instrument used to
measure the amount
of rainfall
The wettest place
on the earth is
Mount Waialeale.
This soggy
mountain is
on the island of
Kauai in Hawaii.
It receives about
12 meters of rain
a year. This rain
comes from trade
winds carrying
rain clouds up
the side of the
mountain.
Precipitation
Chapter 15 introduced four kinds of precipitation: rain, snow,
sleet, and hail. If any precipitation falls, a weather report usually
tells you how much. A rain gauge measures the amount of
rainfall. As you can see, a rain gauge is a container that collects
rain. A scale along the side shows the amount in centimeters or
inches. Snow depth is usually measured simply by inserting a
meterstick in a flat area of snow. Hail can be measured in two
ways: by its depth on the ground and by the diameter of the
hailstones.
Rain gouges come in different shapes and sizes. To accurately measure
rainfall, rain gauges should be placed in open areas.
Weather and Climate
Chapter 16
Lesson 1
R E V I E W
Write your answers to these questions on a sheet of paper.
1. What is weather?
2. How does a thermometer work?
3. What does a change in air pressure tell you about the
weather?
4. Why does air pressure drop as you go higher in the
atmosphere?
5. What weather condition does each of these instruments
measure: barometer, thermometer, rain gauge, anemometer,
psychrometer?
T* A T * A T * A T * A T * A T * A T * A T * A T * A T * A T * A T * A T * A T * A T * A T
Science at Work
Atmospheric Scientist
A scientist who studies the atmosphere is called an atmospheric scientist. These specialists
study the atmosphere's properties and patterns. They also study how weather affects
the environment and how people affect the atmosphere.
Atmospheric scientists collect air samples and gather
data from weather satellites, Doppler radar, and
weather balloons. They use this information to create
computer models of the atmosphere and to design
experiments.
Atmospheric scientists predict long-term weather
changes. They research the effect of pollution on
clouds. They study how processes in the ocean
and on the sun change weather. They design better
instruments and give advice to government and
industry leaders.
•ft
1
1
^
Qfl^^^l Atmospheric scientists must have at least a bachelor's
degree in meteorology, atmospheric science, or a
related science field. A graduate degree is often
helpful.
People who want to work in this field should have
strong computer and mathematics skills. A good
atmospheric scientist is creative, patient, organized,
and stays up-to-date on research methods.
356
Jnit 2 Earth Science
Lesson
Weather Patterns and Predictions
Objectives
To predict the weather, meteorologists need data from many
places. At about 10,000 weather stations worldwide,
measurements are taken at the exact same time several times a
day. In the United States, the National Weather Service (NWS)
collects these data for meteorologists to use.
After reading this
lesson, you should
be able to
+ explain how
fronts, highs,
and lows affect
weather.
+ read the
information on
a weather map.
+ describe types of
storms
Air mass
Large section of the
atmosphere with the
same temperature and
humidity throughout
Front
Moving boundary line
between two air masses
Warm front
Boundary ahead of a
warm air mass that is
pushing out and riding
over a cold air mass
Cold front
Boundary ahead of
a cold air mass that
is pushing out and
wedging under a warm
Air Masses and Fronts
Weather data from a large area of the earth show meteorologists
where air masses are located. An air mass is a huge body of the
lower atmosphere that has similar temperature and humidity
throughout. An air mass can be warm or cold. It can have a lot
of water vapor or very little. Air masses are so large that two or
three of them can cover the United States. As air masses move,
they bring their weather to new places.
A front is a moving boundary line between two air masses. A
warm front occurs where a warm air mass glides up and over a
cooler air mass. As the warm air rises, it cools and water vapor
condenses. Typically, high cirrus clouds appear. Low stratus
clouds follow. The barometer falls continuously, and a period
of steady precipitation begins. When the front passes, skies clear
and the barometer rises. The temperature rises as warm air
replaces the cooler air.
A cold front occurs where a cold air mass pushes out and wedges
under a warmer air mass. The warm air mass rises quickly. If the
warm air mass has a lot of water vapor, towering storm clouds
form quickly. Heavy precipitation follows, but only for a short
period of time. Several hours after the front passes, the weather
becomes clear and cool.
Weather and Climate
Chapter 16
357
Highs and Lows
High
Cold area of high air
pressure
Low
Warm area of low air
pressure
Isobar
Line on a weather map
connecting areas of
equal air pressure
Cold air is more dense than warm air. Therefore, cold air exerts
more pressure on the earth's surface than does warm air. A cold
air mass, then, is usually an area of high pressure, or a high.
Highs often have fair weather. Look at the map below. You can
see that air moves outward from a high in a clockwise rotation.
However, air moves into an area of low pressure, or a low. The
air coming into a low is warm and rotates counterclockwise.
Lows often have clouds and precipitation. On a map, lines called
isobars connect areas of equal pressure. Isobars form a circular
pattern around highs and lows.
In most of the United States and Canada, weather moves from
west to east. Therefore, a high passing through Oklahoma may
soon pass through Arkansas. The high will likely bring similar
weather to both places.
Weather Maps
As you can see, meteorologists must consider a lot of data to
develop a weather forecast. They organize these data on weather
maps, like the one above. Weather maps generally include
information about precipitation, cloud cover, air masses, highs,
lows, and fronts. Weather maps may also include isobars,
temperatures, wind speeds, and wind directions.
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Unit 2
lltirth Science
Tornado
Powerful wind storm
with a whirling, funnelshaped cloud and
extremely low pressure
Hurricane
Severe tropical storm
with high winds that
revolve around an eye
Heat lightning is the
result of high
temperatures.
Fact: Heat lightning
has nothing to do
with heat. It is simply
lightning from
thunderstorms far
away. Heat lightning
is usually seen close
to the horizon. This
explains why it
appears orange or
red. When you look
at the horizon, you
are looking through
the troposphere.
The particles in the
troposphere scatter
the light you see.
Storms
Storms are violent kinds of
weather. They are caused by
rapid changes in the
movement of air masses.
Storms usually include
precipitation and high winds.
Thunderstorms occur when
warm air is forced upward by a
cold front. Large, dark, cumulus
clouds form. Such clouds arc
+ = positive electrical charge
also called thunderheads. These
- - negative electrical charge
clouds produce heavy rain and
sometimes hail. They also produce lightning and thunder.
The diagram above shows how lightning forms.
A tornado is a small but powerful wind storm with a whirling,
funnel-shaped cloud. Tornadoes sometimes form in thunderstorms when warm, humid air rushes up to meet cool, dry air.
Tornadoes have very low air pressure and can rotate at speeds
up to 450 kilometers per hour. When they touch the ground,
they can uproot trees, toss cars, and destroy houses. Tornadoes
last for a very short time.
A hurricane is a large tropical storm that often covers thousands
of square kilometers. Winds spiral toward the center of the
storm, with speeds up to 320 kilometers per hour. At the center of
a hurricane is an area of calm air called the eye that is surrounded
by spiraling clouds.
All hurricanes form over the ocean near the equator. They
collect warm, moist air and begin to spin. They grow stronger
over the warm tropical water. As hurricanes approach land,
their wind pushes the water of the ocean against the shore, and
Hooding occurs. Hurricanes may drop tremendous amounts of
rain as they move inland, causing further damage. Hurricanes
lose their force as they continue to move over land because they
are no longer fed by the heat and moisture of tropical seas.
Friction with the land also slows the winds of the storm.
Weather and Climate
Chapter 16
359
Lesson 2
R E V I E W
riBMMMWM^H
^^••r
Write your answers to these questions on a sheet of paper.
1. What organization collects and analyzes weather data?
2. How is a cold front different from a warm front?
3. What is the difference between a high and a low?
4. What are isobars?
5. Name three kinds of information found on a weather map.
6. How does a thunderstorm form?
7. What is lightning?
8. What is a tornado?
9. Under what conditions does a hurricane form?
10. What causes a hurricane to lose its force?
Doppler Radar
The ability to predict weather events has improved greatly
in the last century. Even as recently as 15 years ago,
meteorologists could provide only a two-day forecast. Today,
improved technology helps them provide a mostly accurate
four-day forecast.
One of the tools that meteorologists use is a Doppler radar
system. This type of radar uses a high-powered antenna that
rotates and sends out radio waves. Some of these waves
bounce off raindrops or snowflakes in the air and return to the
antenna. A computer detects and measures how these waves
have changed. It also measures the time it took for the waves
to return. From this information, the computer calculates the
distance and direction of the precipitation. Wind speed and
direction also can be calculated.
This information is used to create a Doppler map. The map
shows the locations and amounts of precipitation. You have
probably seen a Doppler map on television weather reports.
Meteorologists are trained to use these maps and other
resources to understand and predict weather.
360
Unit 2
Earth Science
I N V E S T I G A T I O N
Using a Weather Map
Purpose
map without
weather
symbols
How can you show weather conditions on a map? In this
investigation, you will make and interpret a weather map.
Procedure
1. On your map, copy the weather information from
the weather map on page 362. Copy the legend of
symbols, too.
2. Show that it is raining across southern Florida.
3. Show that snow is falling in Minnesota and Ontario
behind the cold front.
4. Show that a warm front is occurring across Alabama,
Georgia, and South Carolina and heading toward Florida.
5. Show that it is now cloudy in Honolulu, Hawaii, and
partly cloudy in Juneau, Alaska.
Questions and Conclusions
1. Which cities have clear skies?
2. Which kind of front is heading toward Dallas and
Chicago? What kind of weather will these cities have after
the front passes them?
3. From your map, predict what will happen to temperatures
in Florida tomorrow. Explain your answer.
4. Suggest two more symbols that could be added to your
map. Explain the symbols. How do they make the map
more useful?
Weather and Climate
Chapter 16
361
O Clear
3 Partly cloudy
Cloudy
Cold front
WWW*
Warm front
Explore Further
Compare local weather maps for two days in a row. How
accurate was the first day's forecast? Did the fronts move as
expected? Are there any new fronts? From which direction
did they arrive?
362
Unit 2
Earth Science
World Climates
Objectives
After reading this
lesson, you should
be able to
+ compare and
contrast the
three world
climate zones.
^ identify factors
that affect climate.
Climate
Average weather of
a region over a long
period of lime
What kind of weather do people have on the other side of the
world? It may be similar to yours. Scientists have identified global
patterns in weather.
Climate Zones
Like weather, climate describes conditions of the atmosphere.
Weather is the state of the atmosphere at a given time and
place. Climate is the average weather of a region over a long
period of time. A region's climate depends on two kinds of
measurements:
+ The average temperature pattern during a year
+ The average amount of precipitation in a year
The climates of the world are divided into three major groups,
called climate zones. Find each zone on the map. Refer to this
map as you learn more about these zones.
60 N
60° N
60 S
60 S
Weather and Climate
Chapter 16
363
The mild climates
in areas near large
bodies of water
are called marine
climates. The more
extreme climates
in areas far from
water are called
continental
Y\y
1
Note
During the last 10
years, scientists
have noticed
unexpected
melting of glaciers
and shifts in the
Arctic Ocean
currents. To
understand what is
happening,
meteorologists are
working with
NASA, the National
Aeronautics and
Space
Administration.
Using equipment
mounted on
satellites, NASA
scientists collect
detailed pictures of
the Arctic region.
These images allow
meteorologists to
understand
changes in the
polar weather and
climate.
364
Unit 2
Polar climates are marked by generally cold temperatures. There
is little precipitation in these climates, and it is usually in the
form of snow. The temperatures are so low that very little snow
melts. Polar climates generally extend from the poles to about
60° latitude. They also exist at very high elevations on mountains.
Temperate climates generally extend from 60°N latitude to
the tropic of Cancer and from 60°S latitude to the tropic of
Capricorn. These climates feature the greatest changes in
weather. There are four different weather seasons in these
climates, where winters are cold and summers are warm.
Tropical climates occur near the equator between the tropic of
Capricorn and the tropic of Cancer. These climates are marked by
the highest average temperatures on the earth. Tropical climates
are also the most humid regions. There is little variation in the
kind of weather from one month to the next.
Each of the three major climate zones are further divided into
climate regions. The table on the page 365 provides some
information about these regions.
Factors That Affect Climate
Why is one climate different from another? The main factor
is the angle at which sunlight hits the earth. Because the earth
is a sphere, sunlight hits the tropics more directly than areas
toward the poles. The more direct sunlight provides warmer
temperatures.
Climate is also affected by how high a place is above sea level.
The temperatures in a mountain region are cooler than the
temperatures in a nearby valley. In general, higher places tend
to be cooler. This is why you can find snow-capped mountains
near the equator.
The nearness of large bodies of water also affects climate. In
general, areas that are close to an ocean or a large lake get more
precipitation than areas farther from water. Water heats up and
cools off more slowly than land. As a result, areas near large
bodies of water have more mild temperatures than areas far
from water.
Earth Science
Polar Climates
Temperatures below
freezing
Ice cap climate
Precipitation less than
25 centimeters per year
No visible
plant life
Temperatures slightly
higher than ice cap
Tundra climate
Precipitation less than
25 centimeters per year
Mosses and
small shrubs
Short summer, cold winter
Subarctic climate Precipitation 25-30
centimeters per year
Small pines,
spruce, and fir
Temperate Climates
Temperatures generally
above freezing
Marine west coast climate
Precipitation 50-76
Thick evergreen
centimeters per year
forests
— Deserts and steppes —
Warm to hot summer,
cold winter
Precipitation less than
25 centimeters per year
Cactus in deserts,
grasses in steppes
Warm summer,
mild and wet winter
— Mediterranean climate —
Precipitation
Scattered trees,
25 centimeters per year
low shrubs
Warm and humid
summer, mild winter
Humid subtropical climate
Precipitation 76-165
Heavy plant
centimeters per year
growth and forests
Warm and humid
summer, cold winter
Humid continental climate
Precipitation
Hardwood and
76 centimeters per year
softwood forests,
grass prairies
Tropical Climates
Always hot and humid
- Tropical rain forest —
Precipitation
254 centimeters per year
Very thick forests
and plant growth
Dry and relatively hot
- Tropical desert —
Precipitation less than
25 centimeters per year
Almost no
plant life
Humid and warm summer,
dry and cool winter
Savannah
Precipitalion 76-152
centimeters per year
Weather and Climate
Scattered trees and
shrubs, tall grasses
Chapter 16
365
Lesson 3
R E V I E W
Write your answers to these questions on a sheet of paper.
1. Where do polar climates occur?
2. Where do tropical climates occur?
3. Which climate zone has warm summers and cold winters?
4. How does height above sea level affect climate?
5. What effect does a large body of water have on climate?
Science in Your Life
What is your climate zone?
Now that you have learned about climate zones, identify the zone you live in. How
would you describe the climate in your zone? If you have friends or family who live
in other climate zones, compare your zone with theirs. Do you think you'd rather
live in their climate zone?
What kinds of severe weather occurs in your climate zone? How would you know
if severe weather was predicted for your area? Local newspapers provide important
weather information. They may also show radar and satellite images of weather
patterns that could affect your area. Radio stations regularly broadcast weather
reports.
Local Forecast
Friday
56
Sunny
Are you prepared for severe weather? In your class or at home, discuss what you
should do in a weather emergency. How can you prepare now for severe weather?
The Federal Emergency Management Agency recommends that you have a disaster
supply kit ready in case of a weather emergency. The kit should include water, a
first-aid kit, a flashlight, a radio, a few basic tools, extra clothes, canned food, and
a can opener.
366
Unit 2
Earth Science
Chapter 7 6 S U M M A R Y
Weather is the state of the
atmosphere at a given time
and place.
At a cold front, cold air pushes
under warmer air. A short storm
often results.
To study weather, meteorologists
gather information about air
temperature, air pressure,
humidity, wind speed, wind
direction, type of precipitation,
and amount of precipitation.
Data about fronts, air masses,
highs, and lows are recorded
on weather maps and used to
predict weather.
A barometer measures air
pressure. A psychrometer
measures relative humidity.
An anemometer measures
wind speed. A wind vane
shows wind direction.
An air mass is a large body
of air near the earth's surface.
It has the same temperature
and humidity throughout.
Fronts are the moving
boundaries of air masses.
Storms are severe weather
conditions and include
thunderstorms, tornadoes,
and hurricanes.
Climate is the average weather
of a region over a long period
of time.
The major world climates are
divided into three zones: polar,
temperate, and tropical.
Climate is affected by the angle
of sunlight, height above sea
level, and nearness of large
bodies of water.
At a warm front, warm air glides
up and over cooler air. Steady
precipitation often results.
air mass, 353
air pressure, 352
anemometer, 354
barometer, 352
climate, 363
cold front, 357
front, 357
high, 358
humidity, 353
hurricane, 359
isobar, 358
low, 358
psychrometer, 353
rain gauge, 355
relative
humidity, 353
tornado, 359
warm front, 357
weather, 351
wind vane, 354
Weather and Climate
Chapter 16
367
Chapter 16 R E V I E W
Vocabulary Review
Word Bank
Choose the word or phrase from the Word Bank that best
matches each phrase. Write the answer on your paper.
1. tropical storm that forms over an ocean
air mass
anemometer
barometer
climate
2. instrument for measuring air pressure
humidity
3. state of the atmosphere at a given time and place
hurricane
isobar
psychrometer
4. large section of the atmosphere having the same humidity
and temperature throughout
tornado
5. storm with a dangerous funnel cloud
weather
6. instrument for measuring wind speed
7. instrument for measuring relative humidity
8. average weather over a long period of time
9. line on a weather map connecting areas of equal
air pressure
10. amount of water vapor in the air
Concept Review
Choose the word or phrase that best completes each sentence.
Write the letter of the answer on your paper.
11. In an area of low pressure, the air coming in is
A cold
C rotating clockwise
B warm
D dense
12. The force of the atmosphere against the earth's surface
is
A air pressure
B air temperature
13. A wind vane shows
A altitude
B wind speed
368
Unit 2
Earth Science
C wind
D precipitation
C air pressure
D wind direction
14. Thunderstorms occur when
.
A warm air is pushed up by a cold front
B cold air is pushed up by a warm front
C moist air over the ocean begins to spin
D an air mass stalls
15. A moving boundary between two air masses is called
a(n)
.
A eye
B front
C isobar
D storm
16. A hurricane forms over a(n)
A ocean
C forest
B prairie
D mountain
17. The
climate zone has warm summers and
cold winters.
A polar
B tropical
C temperate
D tundra
18. A warm front often brings
.
A cirrus clouds
C fair conditions
B cool weather
D steady rain
Critical Thinking
Write the answer to each of the following questions.
19. Two cities are located in the temperate climate zone. One
city is located on the coast at sea level. The other city is
located in the mountains, high above sea level. How would
you expect the climates of the two cities to be the same and
different? Explain your answer.
20. If a high pushes out a low in your area today, what weather
changes would you expect?
To prepare for a test, study in short sessions rather than in
one long session. During the week before the test, spend time
each evening reviewing your notes.
Weather and Climate
Chapter 16
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Chapter
The Solar System
T
he center of the solar system is the sun. Even though
it is 150 million kilometers away, the sun affects us in
many ways. For example, huge explosions, called solar
flares, sometimes move outward from the sun's surface. Solar
flares send electrically charged particles into space. Some of
these particles reach the earth and cause static on radios. The
particles can also change the amount of power in electric lines.
In Chapter 17, you will learn more about the sun, planets, and
other objects in the solar system.
Organize Your Thoughts
Solar system
Comets
Goals for Learning
To explain what the solar system is
To identify the four inner planets
To identify the five outer planets
To tell something about each planet
To describe the motions and positions of the planets
To compare comets and asteroids
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