Water and Weather

Chapter Seven: Oceans

• 7.1 Introduction to Oceans

• 7.2 Waves

• 7.3 Shallow Marine Environments

• 7.4 The Ocean Floor

Investigation 7B

• What is the relationship between water depth and wave speed?

Wave Speed

7.2 Waves

• Waves are caused by a disturbance moving forward.

• In the case of water waves, the water moves up and down as the disturbance moves forward.

7.2 Making waves• Waves occur as a repeating pattern of

crests and troughs.

7.2 Making waves• The amplitude of a wave is the distance

between a wave crest or trough and the average level of motion.

• Wavelength is the length of one complete wave.

7.2 More about waves

• A wave causes a circular motion in the water as it passes by.

• Water waves have predictable behaviors.

7.2 More about waves

• The seagull and the dolphin experience the same wave, but the dolphin’s circular path (below the surface) is smaller than the seagull’s.

• They may be no wave motion below the dolphin.

7.2 Wind causes waves

• Most ocean waves are caused by friction between the wind and the ocean surface.

• Fetch is the amount of open water over which wind blows.

7.2 What happens when waves meet

• When waves formed in different places come together, the waves add to and subtract from each other.

7.2 Tsunamis compared to wind waves

• A tsunami is a huge wave made by a large disturbance like an underwater earthquake, landslide, or volcanic eruption.