1. How are waves formed and what are the characteristics of waves?
Ocean Waves
Essential Question:
How are waves formed and what are the characteristics of waves?

3. What is a wave?
A Wave is the movement of energy through a body of water
Most waves form when winds blowing across the water’s surface transmit their energy to the water

4. How do waves differ? Wave Size: Wave Energy:
The size of the wave depends on the strength of the wind and on the length of time it blows
Gentle breeze = small ripples on the surface
Strong winds = larger waves
Longer distances that the wind blows build up bigger waves
Wave Energy:
Although waves may appear to carry water towards the shore, the water does not actually move forward
The energy of the wave moves towards the shore but the water remains in place

5. How do waves move?
As the wave passes, water particles move in a circular path
They swing forward and down with the energy of the wave, then back up to their original position
Winds affects the water at the surface more than it affects the deep water
Below a certain depth, the water does not move at all

6. What are the characteristics of waves?
Crest is the highest part of a wave
The horizontal distance between crests is the wavelength
Waves are also measured by their frequency, or the number of waves that pass a point in a certain amount of time
The trough is the lowest part of a wave
The vertical distance from the crest to the trough is the wave height

7. What are the characteristics of waves?
Click picture for animation

8. How do waves change near the shore?
The white capped waves that crash onto the shore are usually called “breakers”
As the wave approaches the shore the water becomes shallower
The bottom of the wave begins to touch the floor causing the wave to slow down
As the speed decreases, their shapes change
Near the shore, wave height increases and wavelength decreases
When a wave reaches a certain height, the crest of the wave topples

9. Waves not formed by wind
Waves can also be formed below the ocean surface
This type of wave is known as a tsunami and is usually caused by an earthquake beneath the ocean floor
The abrupt movement of the ocean floor sends pulses of energy through the water above it
When tsunamis reach the coast, they can be as devastating as an earthquake on land

10. How do waves cause beach erosion?
From day to day, waves remove sand and bring new sand at about the same rate
Waves shape a beach by eroding the shore in some places and building it up in others
Waves can carve rocky shorelines into tall cliffs and arches

11. Self Check: How do waves form?
Which wind could give more energy to water- a strong wind or a gentle breeze?
What is the name for the distance between the crest and trough of a wave?
Why do waves slow down close to the shore?
What is the source of energy for a tsunami?