Chapter 21 Section 2 Handout

Ocean Waves

Matching

1. wave period2. crest3. wave height4. wave5. wavelength6. trough

a. the lowest point between two crests of a wave

b. the vertical distance between the crest and the trough of a wave

c. a periodic disturbance in a solid, liquid, or gas as energy is transmitted through it

d. the highest point of a wavee. the time required for two

consecutive wave crests to pass a given point

f. the horizontal distance between two consecutive crests or two consecutive troughs

7

• The formula for calculating the speed at which a wave moves is– wave speed = wavelength / wave period

8

• Moving air caused by the uneven heating of Earth’s atmosphere is called _______.– wind

9

• What causes small waves or ripples to form on the ocean?– Friction from moving air and water.

10

• What causes a wave to become larger?– The longer the wind blows from a given

direction, the more energy is given to water.

11

• Explain why larger wave tend to grow larger and smaller waves die out.– Large waves have a larger surface area and

receive more energy from wind than smaller waves.

20

• What kind of wind produces very large waves?– Steady high winds that blow across a long

fetch.

21

• What kind of wind produces choppy water with waves of various heights and lengths?– strong, gusty winds

22

• One of a group of long, rolling waves of similar size is called a(n) ____________.– swell.

23

• What causes a whitecap to form?– When winds blow the crest of a wave off.

24

• Why could whitecaps possibly have an effect on climate?– They reflect solar radiation keeping the ocean

water cool.

25

• At what point does a wave touch the ocean bottom in shallow water near the coastline.– Where the depth of water is about half the

wavelength.

26

• What causes a wave near the coastline to break?– The bottom of the wave is slowed by friction

but the top of the wave continues moving fast.

27

• A foamy mass of water that washes onto the coastline is called a(n) ________.– breaker.

28

• What is the height of a wave when it breaks?– One to two times the height of the original

wave.

39

• A current that forms when waves approach the beach at an angle is called a(n) ______________.– longshore current.

40

• Longshore currents flow _________ to the shore.– parallel

41

• Explain how a sandbar forms.– If there is a bay or an inlet along the shoreline

where waves retract, sand carried by longshore currents is deposited as wave energy lessons.

42

• Which of the following is the most common cause of tsunamis?– earthquakes on the ocean floor

43

• Why is it incorrect to call a tsunami a tidal wave?– because a tsunami is not caused by tides

44

• The wave height of a tsunami in deep water is usually– less than 1 m.

45

• The wavelength of a tsunami in deep water may be as long as– 500 km.

46

• A tsunami has a huge amount of energy because of– its long wavelength.

The End

• http://www.youtube.com/watch?v=Ok5LH8RqrV4&NR=1