U5-Lesson 2: Ocean Waves & Tides

Unit 5: Oceanography
Lesson 2: Ocean Waves & Tides

WAVES

Waves—sound, water, light, earthquake, etc.--are energy passing through a medium (water, air, rock).

OCEAN WAVES

•An ocean wave is the movement of energy through a body of water.

How waves form:

•Most waves form when winds blows across the surface of the water transferring their energy to the water.

Wave Height

•Wind speed, duration (length of time wind blows), and fetch (the distance it blows over open water) determine how high a wave grows.

Wave Parts

•The highest part of the wave is called the crest.

•Distance from trough to crest is called wave height.

•Distance from crest-to-crest or trough-to-trough is called wave length.

•Lowest part of wave is called the trough.

•Tides are the rise and fall of ocean water that occurs every 12.5 hours. The water will rise for about six hours, then falls about six hours. Tides are mostly caused by the moon’s gravitational pull on the Earth.

Tides

Multiple Choice

The size of a wave in the open depends on what?

• the strength of the wind blowing across the water's surface

• particle motion

• wave frequency

• the moon's gravitational pull

Multiple Choice

What happens to the particle motion of water particles as you travel deeper beneath the ocean's surface?

• water particles move in bigger circles

• water particles move in smaller circles

• the movement of water particles stays the same

• the movement of water particles becomes irregular

Multiple Choice

All the following determines how high a wave will be except?

• wind speed

• duration

• fetch

• phase of moon

Multiple Choice

What happens to a wave's height as it approaches shore?

• it's height decreases and its wavelength increases

• its height and wavelength decrease

• its height increase and its wavelength decreases

• its height and wavelength increase

Multiple Choice

What's the difference between wave and tide?

• Wave - generated by wind; Tide - by the sun

• Wave - generated by the sun; Tide - by the moon

• Wave & Tide both generated by the wind

• Wave - generated by the wind; Tide - by the moon