Coasts Flashcards
What is a crest?
The top of the wave.
What is a trough?
The base of a wave.
What is wave height?
The distance from the trough to the crest.
What is wave length?
The horizontal distance between two crests.
What is wave frequency?
The number of waves breaking per minute.
What is fetch?
The distance a wave has travelled.
What is swash?
The wave moving up the beach by the energy from the wind.
What is backwash?
The wave moving back down the beach under the influence of gravity.
What are the features of a constructive wave?
Long wave length, low energy, low wave height, gently sloping, strong swash, weak backwash, transports sediment up the beach and a shallow beach.
What are the features of a destructive wave?
Small wave length, high energy, high wave height, steep wave front, weak swash, strong backwash, takes sediment from the beach, plunges onto a steep beach so it doesn’t travel much.
What is weathering?
The breaking down of rock by day-day atmospheric changes such as temperature and precipitation.
What are the two types of weathering?
Chemical weathering and mechanical weathering.
What are two example of mechanical weathering?
Salt weathering and freeze thaw weathering.
What are two examples of chemical weathering?
Carbonation and oxidation.
What is salt weathering?
Where salt is in rocks when the sea is on it, then it dries and the salt expands, similar to freeze thaw.
What is freeze thaw weathering?
When water fills a crack, then the water freezes in the night and the crack is widened as it expands by 9%. This repeats until the size increases of the crack so much the rock falls off making scree.
What is mass movement and what are 3 examples?
Mass movement is the downhill movement or rock, soil or mud under the influence of gravity. e.g. slides, falls and slumping.
What is sliding?
Material moving downhill that does not lose contact with the slope.
What is falling?
Material moving vertically where material does lose contact with the slope.
What is slumping?
A curve slip plane where material rotates backwards as it moves downhill.
What are the 4 methods of erosion?
Hydraulic action, abrasion, attrition and solution.
What is hydraulic action?
The sheer force of waves pounding cliffs. The surge of water compresses air into cracks creating an explosion effect.
What is abrasion?
The scratching and scraping of cliff faces as sand and shingle is thrown at a cliff face.