Coasts

Question 1

How does freeze-thaw weathering break up rock?

Answer 1

Water enters rock that has cracks
When the water freezes it expands, which puts pressure on the rock
When water thaws it contracts, which releases the pressure on the rock
Repeated freezing and thawing widens the cracks and causes the rock to break up

Question 2

What are the three types of mass movement?

Answer 2

Slides
Slumps
Rockfalls

Question 3

Give the characteristics of destructive waves

Answer 3

They have a high frequency and are high and steep

Their backwash is more powerful than their swash, so material is removed

Question 4

Give the characteristics of constructive waves.

Answer 4

Have a low frequency and are low and long

Their swash is more powerful than the backwash, so material is deposited

Question 5

What are the three types of erosion caused by waves?

Answer 5

Hydraulic power
Abrasion
Attrition

Question 6

Describe hydraulic power

Answer 6

Waves crash against rocks and compress the air in the cracks. This puts pressure on the rock.
Repeated compression widens the cracks and causes bits of rock to break off

Question 7

Describe abrasion

Answer 7

Erodes particles on the water scrape and rub against rock, removing small pieces

Question 8

Describe attrition

Answer 8

Erodes particles in the water collide, break into smaller pieces and become more rounded

Question 9

Explain how material is transported by longshore drift

Answer 9

Waves follow the direction of the prevailing wind
They usually hit the coast at an oblique angle
The swash carries material up the beach, in the same direction as the waves
The backwash then carries material down the beach at right angles, back towards the sea
Over time, material zigzags along the coast

Question 10

Apart from longshore drift, what are the four other processes of transport?

Answer 10

Traction
Saltation
Suspension
Solution

Question 11

When does deposition occur?

Answer 11

When water carrying sediment loses energy and slows down

Question 12

Give two reasons why the amount of material that is deposited might increase

Answer 12

There’s lots of erosion elsewhere on the coast
Lots of material is transported into the area

Question 13

Describe what hard engineering is

Answer 13

Man-made structures built to control the flow of the sea and reduce flooding and erosion

Question 14

Describe what soft engineering is

Answer 14

Schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion

Question 15

Describe a disadvantage of using sea walls

Answer 15

It creates a strong backwash that erodes under the wall. Expensive to build and maintain

Question 16

What are gabions?

Answer 16

A wall of wire cages filled with rocks, usually built at the foot of cliffs