1. Chapter 21 Section 2 Handout
Ocean Waves

2. Matching wave period crest wave height wave wavelength trough
the lowest point between two crests of a wave
the vertical distance between the crest and the trough of a wave
a periodic disturbance in a solid, liquid, or gas as energy is transmitted through it
the highest point of a wave
the time required for two consecutive wave crests to pass a given point
the horizontal distance between two consecutive crests or two consecutive troughs

3. 7 The formula for calculating the speed at which a wave moves is
wave speed = wavelength / wave period

4. 8
Moving air caused by the uneven heating of Earth’s atmosphere is called _______.
wind

5. 9 What causes small waves or ripples to form on the ocean?
Friction from moving air and water.

6. 10 What causes a wave to become larger?
The longer the wind blows from a given direction, the more energy is given to water.

7. 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.

8. 20 What kind of wind produces very large waves?
Steady high winds that blow across a long fetch.

9. 21
What kind of wind produces choppy water with waves of various heights and lengths?
strong, gusty winds

10. 22
One of a group of long, rolling waves of similar size is called a(n) ____________.
swell.

11. 23 What causes a whitecap to form?
When winds blow the crest of a wave off.

12. 24 Why could whitecaps possibly have an effect on climate?
They reflect solar radiation keeping the ocean water cool.

13. 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.

14. 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.

15. 27
A foamy mass of water that washes onto the coastline is called a(n) ________.
breaker.

16. 28 What is the height of a wave when it breaks?
One to two times the height of the original wave.

17. 39
A current that forms when waves approach the beach at an angle is called a(n) ______________.
longshore current.

18. 40
Longshore currents flow _________ to the shore.
parallel

19. 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.

20. 42 Which of the following is the most common cause of tsunamis?
earthquakes on the ocean floor

21. 43 Why is it incorrect to call a tsunami a tidal wave?
because a tsunami is not caused by tides

22. 44 The wave height of a tsunami in deep water is usually
less than 1 m.

23. 45
The wavelength of a tsunami in deep water may be as long as
500 km.

24. 46 A tsunami has a huge amount of energy because of
its long wavelength.

25. The End