Which waves build up a beach?

constructive waves. Their swash is stronger than their backwash.

the distance of open water over which the wind blows. A longer fetch gives bigger waves.

Which process involves waves hurling pebbles at a cliff?

corrasion. Also called abrasion.

In which direction does backwash move?

straight back down the beach. Gravity pulls it down the steepest slope.

What does longshore drift do?

moves material along the coast. In a zigzag, up at an angle and straight back down.

Where is wave energy concentrated because of wave refraction?

on headlands. The waves bend towards the headlands.

Waves and coastal processes · Cambridge IGCSE Geography

In plain words

The coast is where the sea's energy meets the land. Waves do the work: some build beaches up, others tear them down, and all of them move sand and pebbles along the shore.

7 things to know

Waves are made by wind blowing over the sea. Their size depends on the wind's strength, how long it blows, and the fetch: the distance of open water it blows over.
Constructive waves are low and gentle. Their swash, up the beach, is stronger than their backwash, so they deposit material and build beaches.
Destructive waves are tall, steep and frequent. Their backwash is stronger than their swash, so they remove material and erode the coast.
Erosion processes. Hydraulic action: waves force air into cracks, breaking the rock apart. Corrasion (abrasion): waves hurl sand and pebbles at the cliff. Attrition: pebbles knock together and become smaller and rounder. Corrosion (solution): seawater dissolves some rocks.
Longshore drift moves material along a coast. Waves approach at an angle, so the swash carries material up the beach at that angle. The backwash brings it straight back down. The material moves along in a zigzag.
Wave refraction: waves bend as they reach shallow water, so their energy is concentrated on headlands and spread out in bays.
Deposition happens where waves lose energy: in sheltered bays, and where the coastline changes direction.

Worked example

Explain how longshore drift moves sand along a beach.

The prevailing wind makes waves approach the beach at an angle.
The swash carries sand up the beach in the same direction as the waves.
The backwash carries it straight back down the slope, at right angles to the shore, because of gravity.
Repeated many times, this moves the sand along the beach in a zigzag.

Tips and tricks

Corrasion is the scraping (it has the letters of "abrasion" in it). Corrosion is the dissolving. One letter apart, and often swapped.
Swash goes up the beach. Backwash comes back. Constructive: strong swash. Destructive: strong backwash.

6 questions, about 2 minutes.

It lands in your notebook with its questions as flashcards.

Waves and coastal processes: 6 questions and answers

These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.

Which waves build up a beach?
- constructive waves (the answer)
- destructive waves
- tsunami waves
- storm waves
Their swash is stronger than their backwash.
What is fetch?
- the height of a wave
- the distance of open water over which the wind blows (the answer)
- the speed of the backwash
- the angle of a beach
A longer fetch gives bigger waves.
Which process involves waves hurling pebbles at a cliff?
- hydraulic action
- corrasion (the answer)
- corrosion
- attrition
Also called abrasion.
In which direction does backwash move?
- up the beach at an angle
- straight back down the beach (the answer)
- along the beach
- out to sea at an angle
Gravity pulls it down the steepest slope.
What does longshore drift do?
- erodes cliffs
- moves material along the coast (the answer)
- creates waves
- raises the sea level
In a zigzag, up at an angle and straight back down.
Where is wave energy concentrated because of wave refraction?
- in bays
- on headlands (the answer)
- on the sea bed far offshore
- on sand dunes
The waves bend towards the headlands.

6 questions

Tap an answer and you’ll see straight away whether it’s right, and why.

Worksheet

3 questions, 10 marks. Write your answers on paper, then check them.

Waves and coastal processes

Cambridge IGCSE Geography 0460 · 10 marks · papermunch.org

Name ______________________________ Date ______________

Describe the differences between constructive and destructive waves.[4]
Show answerHide answer
Constructive waves are low and far apart, with a strong swash and a weak backwash, so they deposit material. Destructive waves are tall and close together, with a weak swash and a strong backwash, so they erode.
I got this one
Describe two processes of coastal erosion.[4]
Show answerHide answer
Hydraulic action: waves compress air in cracks in the rock, and the pressure breaks pieces off. Corrasion: waves throw sand and pebbles against the cliff, wearing it away.
I got this one
State two factors that affect the size of waves.[2]
Show answerHide answer
The strength of the wind. The fetch: the distance of open water the wind blows over.
I got this one

Answers: Waves and coastal processes

1. Constructive waves are low and far apart, with a strong swash and a weak backwash, so they deposit material. Destructive waves are tall and close together, with a weak swash and a strong backwash, so they erode.
2. Hydraulic action: waves compress air in cracks in the rock, and the pressure breaks pieces off. Corrasion: waves throw sand and pebbles against the cliff, wearing it away.
3. The strength of the wind. The fetch: the distance of open water the wind blows over.