Waves

Question 1

Describe wave formation

Answer 1

1. Wind creates frictional drag on sea surface.
2. Drag moves water particles in a circular orbit.
3. Orbit becomes elliptical as water becomes shallower.
4. Wavelength decreases and height increases.
5. Wave breaks onto beach

Question 2

Constructive wave’s swash, backwash, frequency, direction of breaker and impact on beach

Answer 2

Strong swash
Weak backwash
6-8 per minute
Forwards- spilling breaker
Depositional impact on beach

Question 3

Destructive wave’s swash, backwash, frequency, direction of breaker and impact on beach

Answer 3

Weak swash
Strong backwash
More than 15 per minute
Downwards- plunging breaker
Erosional impact on beach

Question 4

Describe destructive waves

Answer 4

They destroy beaches.
Waves usually very high and very frequent
Backwash has less time to soak into the sand.
As waves continue to hit the beach there is more
running water to transport the material out to sea.
Common in winter.

Question 5

Describe constructive waves

Answer 5

Build beaches.
Each wave is low.
As the wave breaks, it carries material up the beach in its swash.
The beach material will then be deposited as the backwash soaks into the sand or slowly drains away.
Common in the summer

Question 6

What are swell waves?

Answer 6

Waves generated by storms in the middle of oceans and maintain their energy for thousands of miles.

Question 7

What is the fetch?

Answer 7

The fetch is the distance of open water over which the swell waves move.

Question 8

What is typical of a beach in winter stormy conditions?

Answer 8

Steep, convex profile; swash pushes material up the beach in a spilling breaker.

Question 9

What is typical of a beach in calm summer conditions?

Answer 9

Steep, concave profile; berms eroded by plunging breakers.