1. Wave Action
Section 13.1

2. What is a wave? Wave – movement of energy Wave size depends on:
through a body
Wave size depends on:
strength of wind
length of time wind blows
distance over which wind blows

3. What is a wave? Wave molecules move in a circular motion
Molecules at the surface move in a bigger circle than those that are deeper
At a certain depth, water is not affected by the wave

4. What is a wave? Crest – highest point Trough – lowest point
Wavelength – distance from
crest to crest
Wave height – distance
from crest to trough

5. Wavelength
Wave height
Crest
Trough
Wave Depth is
half the wavelength

6. How waves change near shore
Breakers – white capped waves that crash onto
the shore
Friction on the bottom slows the wave down.
Wave height increases and wave length decreases.

7. How waves change near shore
Tsunamis – usually caused by an earthquake
beneath the ocean floor

8. How waves affect the shore
Longshore Drift – the movement of sand as water washes up and carries sand along the beach

9. How waves affect the shore
Rip current
- a rush of water that flows rapidly back to sea through a narrow opening

10. Waves and beach erosion
Groins
Barrier Beaches
Sand Dunes