Why is "Mixing up constructive and destructive waves" a common mistake in Coastal Processes and Wave Dynamics?

Why it happens: Both involve swash/backwash. How to avoid it: CONSTRUCTIVE = BUILDS (strong swash, weak backwash, deposition). DESTRUCTIVE = TEARS DOWN (weak swash, strong backwash, erosion). Match the noun to the action. Source: 0460 Examiner Reports 2022-2024

Why is "Saying waves are caused by tides" a common mistake in Coastal Processes and Wave Dynamics?

Why it happens: Both involve water movement. How to avoid it: Waves caused by WIND. Tides caused by gravitational pull of MOON and SUN. Separate phenomena.

Why is "Drawing swash perpendicular to the coast" a common mistake in Coastal Processes and Wave Dynamics?

Why it happens: Most beach experiences feel perpendicular. How to avoid it: Longshore drift specifically requires waves at an ANGLE to the coast. If waves break perpendicular, no drift — material moves up and back, not along.

Changing Coastal EnvironmentsCambridge IGCSE Geography 0460

Coastal Processes and Wave Dynamics

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Coastal Processes and Wave Dynamics Study Notes — Cambridge IGCSE Geography 0460 (2024-2026 syllabus)

Waves form from wind energy. Constructive waves build beaches; destructive waves erode. Longshore drift transports sediment along the coast. Same four erosion types as rivers.

What you’ll learn

Mapped to the Cambridge IGCSE 0460 syllabus (2024-2026).

2.1.1 — Describe wave formation and size factors.
2.1.2 — Distinguish constructive and destructive waves.
2.1.3 — Describe longshore drift.
2.1.4 — Identify coastal erosion processes.

How waves form

Wind blows over water → friction → ripples → waves.

Waves are caused by WIND blowing over water. Friction transfers energy from the wind into the water, creating ripples that grow into waves.

Three factors affecting wave size.

Wind STRENGTH — stronger wind = bigger waves.
Wind DURATION — longer it blows, more energy transferred.
FETCH — distance over which the wind blows uninterrupted across water. Longer fetch = bigger waves.

Wave anatomy.

Crest — top of wave.
Trough — bottom.
Wavelength — distance between crests.
Wave height — vertical from trough to crest.
Swash — water moving UP the beach after the wave breaks.
Backwash — water flowing back DOWN to the sea.

Cambridge tip. Mark scheme rewards specific factors — wind STRENGTH, DURATION, FETCH — all three.

Waves caused by WIND.
Size: strength + duration + fetch.
Energy transferred via friction.

See the full worked example for coastal processes and wave dynamics →

Constructive vs destructive waves

Constructive build beaches; destructive erode them.

Constructive waves.

Low height, long wavelength.
Infrequent (6-8 per minute).
Strong SWASH carries material UP the beach.
Weak BACKWASH can't drag it back.
Net result: DEPOSITION → builds up beaches.

Destructive waves.

High height, short wavelength.
Frequent (10-14 per minute).
Weak SWASH.
Strong BACKWASH drags material DOWN the beach.
Net result: EROSION → wears away coastlines.

Trade-off pattern. On stormy days, destructive waves dominate. On calm days, constructive waves slowly rebuild beaches.

Cambridge tip. Memorise: CONSTRUCTIVE = swash > backwash → deposition. DESTRUCTIVE = backwash > swash → erosion.

Constructive: low, long, build (swash > backwash).
Destructive: high, short, erode (backwash > swash).
Storms = destructive; calm = constructive.

See the full worked example for coastal processes and wave dynamics →

Longshore drift

Zig-zag transport along the coast.

Longshore drift moves sediment ALONG the coast in a zig-zag pattern.

Mechanism.

Waves approach the coast at an ANGLE (driven by prevailing wind).
Swash carries material UP the beach AT THAT ANGLE.
Backwash returns DIRECTLY DOWNHILL under gravity (perpendicular to coast).
Each wave shifts sediment slightly ALONG the coast.
Over many waves, the net movement is in the direction of prevailing wind.

Consequence. Builds spits, bars, tombolos. Determines where beaches grow and where they erode.

Waves hit the beach at an angle, swash up the angle, backwash straight down. The zig-zag net-moves sediment along the coast.

Cambridge tip. Diagrams that show ANGLE of incoming waves, the zig-zag, and the prevailing wind direction earn full marks.

Waves hit at angle → swash up angle, backwash straight down.
Net movement along coast in prevailing wind direction.
Source of sediment for spits, bars, tombolos.

See the full worked example for coastal processes and wave dynamics →

How it’s examined

Coastal processes appear on every Paper 1. Most-tested: wave size factors (5 marks), constructive vs destructive (6 marks), longshore drift diagram (6 marks).

Sources: Cambridge IGCSE Geography 0460 syllabus (2024-2026); 0460 Examiner Reports 2022-2024; 0460/12 May/Jun 2024 question paper and mark scheme. Last reviewed 2026-05-09.

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Step-by-step worked examples — Coastal Processes and Wave Dynamics

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1How waves form (5 marks)
Extended• Adapted from 0460/12 May/Jun 2024• waves
Question
Describe how waves form and identify THREE factors that affect wave size. (5 marks)
Step-by-step solution
1. Step 1
  Wave formation (2 marks). Waves form when WIND blows over the surface of water. Friction between wind and water surface creates ripples; sustained wind grows them into waves. Energy is transferred from wind to water.
2. Step 2
  Three factors affecting wave size (3 marks). (a) Wind STRENGTH — stronger wind = bigger waves. (b) Wind DURATION — longer it blows, more energy transferred. (c) FETCH — distance over which wind blows uninterrupted; longer fetch = bigger waves.
Answer
Waves form from wind friction on water. Size depends on strength, duration, and fetch.
2Constructive vs destructive waves (6 marks)
Extended• waves
Question
Distinguish CONSTRUCTIVE and DESTRUCTIVE waves. State ONE example of each. (6 marks)
Step-by-step solution
1. Step 1
  Constructive waves (3 marks). LOW height, LONG wavelength, infrequent (6-8 per minute). Strong SWASH (run up the beach) carries material UP the beach. Weak BACKWASH. Result: DEPOSITION; build up beaches.
2. Step 2
  Destructive waves (3 marks). HIGH height, SHORT wavelength, frequent (10-14 per minute). Weak SWASH; strong BACKWASH drags material DOWN the beach. Result: EROSION; wear away coastlines.
Answer
Constructive: low + long, build up (calm beach). Destructive: high + short, erode (storm coast). Swash vs backwash strength is the key.
3Longshore drift (6 marks)
Extended• transport
Question
Describe the process of longshore drift. (6 marks)
Step-by-step solution
1. Step 1
  Wave direction (2 marks). Waves typically approach the coast at an ANGLE (not perpendicular) determined by the PREVAILING WIND.
2. Step 2
  Swash up at an angle (2 marks). Each wave's swash carries sand and pebbles up the beach AT AN ANGLE (matching the wave direction).
3. Step 3
  Backwash straight down (1 mark). Backwash returns DIRECTLY DOWN the slope (perpendicular to the shore) under gravity.
4. Step 4
  Net movement along coast (1 mark). Over many waves, this creates a ZIG-ZAG transport pattern that moves sediment ALONG the coast in the direction of the prevailing wind.
Answer
Longshore drift = zig-zag transport along the coast. Swash carries material up at angle; backwash returns straight down. Net movement matches prevailing wind direction.
Examiner tip
Top-band candidates explicitly name PREVAILING WIND, SWASH, and BACKWASH. Diagrams help — mark scheme rewards clear arrows showing the zig-zag.

Key Definitions and Keywords — Coastal Processes and Wave Dynamics

Definitions to memorise and the exact keywords mark schemes credit for coastal processes and wave dynamics answers — sharpened from recent examiner reports for the 2026 0460 sitting.

Wave
Examiner keyword
A movement of water energy caused by wind blowing over the surface.
Fetch
Examiner keyword
The distance over which wind blows uninterrupted across water. Longer fetch = bigger waves.
Swash
Examiner keyword
The forward movement of a wave UP the beach after breaking.
Backwash
Examiner keyword
The return of water DOWN the beach toward the sea, under gravity.
Constructive waves
Examiner keyword
Low, long, infrequent waves with strong swash and weak backwash. BUILD UP beaches via deposition.
Destructive waves
Examiner keyword
High, short, frequent waves with weak swash and strong backwash. ERODE beaches and coastlines.
Longshore drift
Examiner keyword
Zig-zag transport of sediment ALONG the coast — swash up at an angle, backwash straight down.
Coastal erosion (types)
Examiner keyword
Same four types as river erosion: hydraulic action, abrasion, attrition, solution.

Common Mistakes and Misconceptions — Coastal Processes and Wave Dynamics

The traps other students keep falling into on coastal processes and wave dynamics questions — taken from recent Cambridge IGCSE 0460 examiner reports and mark schemes — and how to avoid them.

✕Mixing up constructive and destructive waves
0460 Examiner Reports 2022-2024
Why it happens
Both involve swash/backwash.
How to avoid it
CONSTRUCTIVE = BUILDS (strong swash, weak backwash, deposition). DESTRUCTIVE = TEARS DOWN (weak swash, strong backwash, erosion). Match the noun to the action.
✕Saying waves are caused by tides
Why it happens
Both involve water movement.
How to avoid it
Waves caused by WIND. Tides caused by gravitational pull of MOON and SUN. Separate phenomena.
✕Drawing swash perpendicular to the coast
Why it happens
Most beach experiences feel perpendicular.
How to avoid it
Longshore drift specifically requires waves at an ANGLE to the coast. If waves break perpendicular, no drift — material moves up and back, not along.

Practice questions

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Coastal Processes and Wave Dynamics

Short Study Notes in the form of Slides

Short Study Notes — Coastal Processes and Wave Dynamics

Detailed Notes

What you’ll learn

How it’s examined

1How waves form (5 marks)

2Constructive vs destructive waves (6 marks)

3Longshore drift (6 marks)

Wave

Fetch

Swash

Backwash

Constructive waves

Destructive waves

Longshore drift

Coastal erosion (types)

✕Mixing up constructive and destructive waves

✕Saying waves are caused by tides

✕Drawing swash perpendicular to the coast

Practice questions

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