Coasts Waves. How do you get waves like this ? 6R Giant Wave surfing.dv.

CoastsWaves

How do you get waves like this ?

6R Giant Wave surfing.dv

How are waves created?

Wind blows

Friction

Surface of the sea starts to move

What do you think affects the size of waves?

http://www.bbc.co.uk/scotland/education/geog/coastline/enhanced/

So wave size depends on:

1) Strength of wind

2) The fetch (the distance that a wave has travelled)

http://www.bbc.co.uk/schools/gcsebitesize/geography/coastal/coastalprocessesrev1.shtml

What happens as the wave approaches the coast?

(Read and see Waugh p300 Figure 18.1)

Why does a wave break?

What is swash and backwash?

http://www.bbc.co.uk/scotland/education/geog/coastline/enhanced/

http://www.bbc.co.uk/schools/gcsebitesize/geography/coastal/coastalprocessesrev1.shtml

Destructive Waves

•They have a strong backwash compared to the their swash

•They are high in relation to the length of wave

•They are frequent waves (break at a rate of around 15 a min)

Constructive Waves

•They have a weak backwash compared to the their swash

•They are long in in relation to the height

•They are less frequent gentle waves (break at a rate of around 6-

9 a min)

Sort the following facts. Are they about constructive or destructive waves?

• Weak swash & strong backwash• Operate in calm weather• Limited energy• Steep beach angle• High wave height (5-6 metres)• Build up sediment on beaches• Remove sediment from beaches• Gentle sloping beaches• Strong swash & weak backwash • Cause erosion• Break frequently (~15 per minute)• Beach increases in size• Low wave height (about 1 metre high)• Much energy • Operate in storm conditions• Break less frequently (~7 per minute)