Waves

• What is the coast?

  The land along the sea

  Where the land meets the sea

  E.g. beach or cliffs
• What are waves? 

  Waves are a disturbance on the surface of the sea or ocean, in the form of a moving ridge or swell.
• What factors determine wave size and strength?

  • The strength of the wind.
  • How long the wind has been blowing for.
  • The distance the wave has travelled (fetch).
• Swash

  The movement of waves on to the beach - bringing sediment towards the beach 
• Backwash 

  The movement of waves from the beach back out to sea. Taking sediment away from the beach to the sea
• The characteristics of a constructive wave are:

  • strong swash and weak backwash
  • the strong swash brings sediments to build up the beach
  • the backwash is not strong enough to remove the sediment
  • the waves are low and further apart.
  • The beaches are wide and flat
• The characteristics of a destructive wave are:

  • weak swash and strong backwash
  • the strong backwash removes sediment from the beach
  • the waves are steep and close together. 
• Destructive waves are tall and powerful waves that erode the coastline. They crash down on to beaches and drag material away with them. This means that their backwash is greater than their swash. Their power is generated from gravity due to their large wave height and short wavelength. Due to this short wavelength, they have a high wave frequency with between 10 and 15 waves breaking on the shore per minute. They create steep beaches.
• Constructive waves are much weaker than destructive waves. Their swash is greater than their backwash and this results in new material being deposited onto the coastline. This often creates wide, flat beaches. They have a lower wave height and a greater wave length. This means that waves are infrequent, with an average of 10 waves or fewer per minute.