Waves Flashcards
How are waves created
Waves are created when wind blows over the surface of the sea, transferring energy through ‘frictional drag’ , causing the crest of the wave to move
How and where do waves break
Waves break as they approach the shore, due to friction with the sea bed. As friction slows the bottom of the wave, the movement becomes elliptical until the crest collapses at a 1:7 ratio
What 3 factors does wave power depend on
- Wave height
- Wind speed, strength and time blown
- Wave fetch (maximum distance wind has blown over)
What are the 2 types of waves
Constructive and Destructive
What is wave height
distance between a crest and a trough
What is wave length
distance between 2 successive crests
What is wave frequency
number of waves per minute
What is wave period
time taken for 2 successive crests to pass one point
What are the characteristics of a constructive wave
Low height, long wavelength
Low frequency, high period
Elliptical movement
Strong swash, weak backwash meaning they transport sediment up the beach and make them steeper
What are the characteristics of a destructive wave
High height, short wavelength
High frequency, low period
Orbital movement
Weak swash, strong backwash, meaning they erode sediment and make the beach flatter
What happens to wave energy the further they travel
The energy becomes dissipated and they become weaker
What is the equation for wave energy
wavelength x wave height^2
What are the characteristics of a low energy coast
Low wave energy
Deposition exceeds erosion leading to feature like beaches and spits
Example : The Baltic Sea
What are the characteristics of a high energy coast
High wave energy
Erosion exceeds deposition leading to features like headlands and cliffs
Example : The Holderness coast
