GCSE Geography/Coasts/Coastal Landforms
The coastline is made up of a whole sequence of landforms, that owe their existence to the work of waves.
Waves are caused by the wind's friction over the sea surface. The wind tugs at the surface, causing the wave shape to move. The height of a wave depends on the speed of the wind, how long it has been blowing and the fetch. Any increase in any of these factors will cause the wave height to increase.
Wave changes shape in shallow coastal waters, which causes it to break.