The amount of energy that the waves have determines what sort of effect they have on a coastal environment.

If the waves have energy they erode cliffs and rocks.
If the waves have energy they deposit pebbles and sand on beaches.

An exception to this are tidal waves. Tidal waves are formed by earthquakes under the sea.

Experiment
Resources:
plastic tray
water

Pour water into a shallow, plastic tray:

• Try blowing across the surface of water in a tray. What do you notice?
• Now, try blowing gently and then harder. Can you create a storm?
• As you blow, which part of the water is your breath reaching?

Counting Waves

Next time you are at the beach, count the number of waves breaking in 1 minute.
More than 10 waves, the sea is carrying material away. Less than 10 waves, the sea is depositing material on the beach.

Research
Resources:
books
CD-Roms
Internet
newspaper

Find out where tidal waves occur and their impact on people and the environment.

Tsunami