CHAPTER 21 DIRECTED READING WORKSHEET 4111 … · -4 U0 Name Date Class Chapter 21 Directed Reading, continued ... Weather Forecasting Technology (p. 579) 2. A barometer measures

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CHAPTER

411121 DIRECTED READING WORKSHEET

Understanding Weather

As you read Chapter 21, which begins on page 562 of your textbook, answerthe following questions.

Twisting Terror (p. 562)

1. What is Tornado Alley?

2. Name the states that are part of Tornado Alley.

Pre-Reading Questions (p. 562)

Answer these questions in your ScienceLog now. Then later, you'llhave a chance to revise your answers based on what you've learned.

Start-Up Activity (p. 563)

3. What is the purpose of this activity?

Section 1: Water in the Air (p. 564)

4. Weather is the condition of the at acertain time and place.

• The Water Cycle (p. 564)

5. Plants release liquid water into the air. True or False? (Circle one.)

TEXAS EDITION, GRADE 8, UNIT 6 RESOURCES 167

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Chapter 21 Directed Reading, continued

6. Water that flows across land and collects in rivers, streams, andthe ocean is called

7. takes place when liquid waterchanges into water vapor.

8. Rain, snow, sleet, and hail are all forms ofa. condensation. c. precipitation.b. runoff. d. evaporation.

Humidity (p. 565)

9. Take a moment to read the Brain Food on page 565. What makeshair become longer when it is humid?

10. Which kind of air holds the highest amount of water vapor?a. warm airb. medium-temperature airc. cool aird. dry air

11. As air temperature increases, the amount of water that air can

hold

12. Relative humidity compares the amount of water vapor in the airwith the amount of water vaporthat the air can hold at a certain temperature.

13. Air that is holding all the water it can hold at a given temperatureis

14. Relative humidity is given as a

Condensation (p. 566)

15. Why do water droplets form on the outside of a glass of ice water?

16. Condensation happens when coolsfurther.

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17. When air cools to a temperature at which it is completelysaturated with water vapor, we say that the air has reached its

Mid-Section Review (p. 566)

Now that you've finished the first part of Section 1, review what youlearned by answering the Mid-Section Review questions in yourScienceLog.

Clouds (p. 567)

18. What is a cloud made of?

Choose the word in Column B that best matches the definition inColumn A, and write the corresponding letter in the space provided.

Column A Column B

19. cloud that forms in layers a. nimbostratus

b. stratus

c. cirrus

d. cumulonimbus

e. cumulus

20. puffy, white cloud with a flat bottom

21. cloud that produces thunderstorms

22. cloud that produces continuous rain

23. thin, feathery, high-altitude cloud

24. If cirrus clouds get thicker, they indicate that is coming.

25. In Figure 5 on page 568, the prefixes cirro-, alto-, and strato-classify clouds by theira. temperature. c. size.b. shape. d. altitude.

Precipitation (p. 569)

26. Before a cloud drop falls as rain, it must become about its normal size.a. 2 times c. 100 timesb. 10 times d. 1,000 times


Name Date Class


Mark each of the following statements True or False.

27 Sleet forms when rain falls through a layer of freez-ing air.

28 Snow forms when temperatures are so warm thatwater vapor changes directly to a solid.

29 Updrafts of air can send hail back up into the clouds.30. Rain that does not freeze until it hits a surface near the ground is

called

Section Review (p. 570)

Now that you've finished Section 1, review what you learned byanswering the Section Review questions in your ScienceLog.

Section 2: Air Masses and Fronts (p. 571)

1. What causes changes in weather?

2. The air in an air mass has the same and

Air Masses (p. 571)

3. What is a source region?

4. What two characteristics of air masses are represented with atwo-letter symbol on weather maps?a. density and moisture c. moisture and temperatureb. mass and temperature d. shape and mass

5. Give the four letters used to describe the characteristics of airmasses and tell what each letter identifies.


Name Date Class


Fronts (p. 572)

6. Take a moment to read the Brain Food on page 572.Meteorologists first started using the term front to describeweather systems during World War I. They compared air massesto opposinga. armies. c. submarines.b. tanks. d. machine guns.

7. Air masses that form from different areas often don't mix becausethey have differenta. wind speeds. c. clouds.b. air pressures. d. densities.

Choose the type of front in Column B that best matches thedescription in Column A, and write the corresponding letter inthe space provided.

Column A Column B

8. A warm air mass moves over a cold air mass. a. cold frontb. warm frontc. occluded frontd. stationary front

9. A warm air mass is caught between two colderair masses.

10. A cold air mass moves under a warm air massand pushes it up.

11. A cold air mass meets a warm air mass, butnothing happens.

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Section 3: Severe Weather (p. 573)ecC

1. A thunderstorm is one example of weather.

Thunderstorms (p. 574)

O.0 2. Which one of the following atmospheric conditions produces

thunderstorms? (Circle one.)a. Warm, moist air rises rapidly.b. The air near the Earth's surface is cold and dry.c. The atmosphere is stable.d. The atmosphere is bright.

3. Cumulonimbus clouds can reach heights of more than


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4. Lightning takes place when there is a difference incharge between two areas.

5. Thunder is caused by the rapid expansion of airalong a lightning strike.

6. When lightning strikes, energy is transferred tothe air.

Tornadoes (p. 575)

7. What is the relationship between a funnel cloud and a tornado?

Indicate the correct order for the steps in the formation of a tornadoby writing the appropriate number in the space provided.

8. The column of spinning air travels to the bottom ofthe cumulonimbus cloud.

9 Strong updrafts of air turn the column of spinningair to a vertical position.

10 The funnel cloud touches the ground.

11. Wind moving in two different directions causes alayer of air between them to spin.

12. Look at the Brain Food on page 576. What do you call a tornadothat happens over water?a. an aqueous tornado c. a whirlpoolb. a water funnel d. a waterspout

13. In which seasons do most tornadoes in the United States occur?a. late summer and fall c. spring and early summerb. late fall and winter d. winter and early spring

14. Why are tornadoes so dangerous?


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Column A Column B

19. bands of clouds that circle the center a. eyeb. eye wall

c. rain bands

of a hurricane

20. cumulonimbus clouds that cause heavy rainsand strong winds

21. core of warm, calm airr.)-c

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022. What causes most of the damage associated with hurricanes?

c. cold weathera. floodingb. high winds d. lightning

Name Date Class


Hurricanes (p. 576)

15. A tropical weather system is classified as a hurricane when itreaches wind speeds of at least

16. Hurricanes that form over the western Pacific Ocean are called , while those that form over theIndian Ocean are called

17. Hurricanes turn in opposite directions in the Northern andSouthern Hemispheres. True or False? (Circle one.)

18. Where do hurricanes get their energy?

Choose the term in Column B that best matches the description inColumn A, and write the corresponding letter in the space provided.

23. Look at the Astronomy Connection on page 578. The Great RedSpot of Jupiter is most like a(n)

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c. thunderstorm.d. air mass.




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Section 4: Forecasting the Weather (p. 579)

1. What is a weather forecast?

Weather Forecasting Technology (p. 579)

2. A barometer measures An anemometer measures

3. Weather balloons carry electronic equipment that measuresconditions as high as above theEarth's surface.

4. Which of the following conditions is NOT measured by weatherballoons? (Circle one.)a. air pressure c. relative humidityb. precipitation d. temperature


5. Radar is used to determine wind speed and direction.6. Radar can be used to detect the location of precipitation. Weather satellites can measure temperatures at

different altitudes.

Weather Maps (p. 580)

8. Give the full name and initials of two major sources of weatherinformation in the United States.

9. On a weather map, are lines that

connect points of equal

10. What does an isobar line that forms a closed circle show?




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CHAPTER 21 DIRECTED READING WORKSHEET 4111 … · -4 U0 Name Date Class Chapter 21 Directed Reading, continued ... Weather Forecasting Technology (p. 579) 2. A barometer measures