chapter 20 directed reading, · pdf filechapter 20 directed reading, continued 28. what is ......

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Name Date Class

Chapter 20 Directed Reading, continued

28. What is upwelling?

29. During an El Nino event, surface water temperatures along South

America's western coast

Mark each of the following statements True or False.

30. El Nitio affects both surface water and weather patterns.31. El Nirio can occur as often as every 2 years.32. El Nino does not alter weather patterns enough to

cause disasters.

Section Review (p. 541)

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

Section 2: Waves (p. 542)

1. Winds and earthquakes are two possible causes of ocean waves.True or False? (Circle one.)

Anatomy of a Wave (p. 542)

2. Which part of a wave is represented by each letter on thefollowing diagram?

a. c.

b. d.

Wave Formation and Movement (p. 542)

3. Water remains in the same place as waves travel through it.

True or False? (Circle one.)TEXAS EDITION, GRADE 8, UNIT 6 RESOURCES 161

Name Date Class


4. Surface wave energy reaches all the way to the bottom of theocean. True or False? (Circle one.)

Specifics of Wave Movement (p. 543)

5. Using Figure 12 on page 543 as a reference, explain how youdetermine a wave period.

6. What is the equation for wave speed?

Types of Waves (p. 543)

7. Waves can form by all of the following EXCEPTa. wind. d. impact by cosmic bodies.b. landslides. e. earthquakes.c. the phases of the moon.

8. What is the difference between shallow-water waves and deep-water waves?

Read pages 544-545. Then choose the type of wave or current inColumn B that best matches the description in Column A, and writethe corresponding letter in the space provided.

Column A Column B

9. when waves hit the shore at an angle a. longshore current

b. undertoe

c. whitecaps

d. swells

10. move steadily across the ocean

11. break in open ocean

12. moves below and opposite to incoming waves

162 HOLT SCIENCE AND TECHNOLOGY

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13. How do tsunamis form?

14. Explain how a storm surge forms.



Section 3: Tides (p. 548)

1. Which of the following influence tides? (Circle all that apply.)a. Venus c. the moonb. the sun d. Mercury

cn

The Lure of the Moon (p. 548)

2. The sun's gravity is the dominant force affecting the Earth's tides.

True or False? (Circle one.)

3. Which of the following people developed theories on theprinciple of gravitation? (Circle one.)a. Lord Kelvin c. Sir Isaac Newton_0 b. Marie Curie d. Pytheas

4. The pull of the moon's gravity is more noticeable in liquidsQ.)0_0 than in solids because liquids are lighter than solids.

True or False? (Circle one.)

5. Where on Earth do high tides occur? (Circle all that apply.)a. the part of the Earth that is facing the moon• b. the part of the Earth that is directly opposite the part facing

the moonc. the part of the Earth that is facing the sund. any part of the ocean

TEXAS EDITION, GRADE 8, UNIT 6 RESOURCES 163

Name Class


•6. What two factors determine when tides occur?

7. Tides do not occur at the same spots on Earth becausea. the Earth rotates more quickly than the moon revolves

around the Earth.b. the moon revolves around the Earth more quickly than the

Earth rotates.c. the Earth rotates at the same speed that the moon revolves

around the Earth.d. none of the above

8. How long does it take for a point on the Earth that is facing themoon to rotate so that it is facing the moon again?a. 24 hours and 5 minutesb. 12 hours and 50 minutesc. 12 hours and 5 minutesd. 24 hours and 50 minutes

9. Read the Brain Food on page 549 of your textbook. How are dryland tides different from ocean tides?

The Lunar Cycle (p. 550)

10. Why does the moon appear to change shape when we view itfrom the Earth?

•

Date

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Name Date Class


11. Look at Figure 22 on page 550 of your textbook. Then numberthe following phases of the moon to show the order in whichthey occur. Start with the new moon.

waxing gibbous

last quarter

new moon

waning gibbous

first quarter

waning crescent

full moon

waxing crescent

12. When the moon is , the sunlit partthat we see from the Earth grows smaller. When the moon is

, the sunlit part grows larger.

Tidal Variations (p. 551)

13. Since the sun is much larger than the moon, why is the sun'sinfluence on tides less powerful than the moon's influence?

14. The difference between the levels of ocean water at high tide and

low tide is called a tidal variation. True or False? (Circle one.)

Read page 551 to determine whether the statements below are truefor spring tides or neap tides. Write ST for spring tides and NT forneap tides in the space provided.

15. occur during the first and third quarters of the moon

16. have the largest daily tidal range

17 occur when the sun, Earth, and moon line up withone another

18 occur when the sun, Earth, and moon form a 90°angle

19. occur when the sun's and moon's gravitational forcespull on the Earth in the same direction

• 20. occur when the sun's and moon's gravitational forcespull on the Earth in opposite directions

TEXAS EDITION, GRADE 8, UNIT 6 RESOURCES 165

•

•

Name Date Class


Tidal Energy (p. 552)21. What are two advantages of using tidal energy to generate

electricity?

22. Tidal power plants are built in areas with small tidal ranges.True or False? (Circle one.)

23. Why do some people oppose tidal power plants?

Tides and Topography (p. 553)

24. Tides can be accurately predicted once the has been measured at a certainpoint over a period of time.

25. Where do tidal bores occur? (Circle all that apply.)a. narrow bays c. oceansb. inland rivers d. estuaries




chapter 20 directed reading, · pdf filechapter 20 directed reading, continued 28. what is ......

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