Sources of energy: Waves

Question 1

wave height is

Answer 1

the height difference between a wave crest and the neighbouring trough

Question 2

wavelength (amplitude) is

Answer 2

the distance between successive crests

Question 3

wave frequency (wave period) is

Answer 3

the time it takes for one wave to travel the distance of one wavelength, or the time between the crest and the following crest passing a fixed point

Question 4

as waves approach shallow water,

Answer 4

• friction with the seabed increases and the base of the wave slows down
• this means the wave gets taller and steeper until the crest plunges forward and and breaks

Question 5

backwash is

Answer 5

the action of water receding back down the beach towards the sea

Question 6

a constructive wave is

Answer 6

a wave with a low wave height , but with a long wavelength and low frequency of 6-8 waves per minute
their swash is more powerful than their backwash, so more sediment is deposited onto the beach than is removed

Question 7

a destructive wave is

Answer 7

a wave with a high wave height and steep form and high frequency of 10-14 waves per minute
their backwash is more powerful than their swash, so more sediment is removed than is deposited

Question 8

swash is

Answer 8

the rush of water up the beach after a wave breaks

Question 9

• most beaches are subject to an alternating cycle of…………………and ………………………waves.
• this is because:
• this is called:

Answer 9

• most beaches are subject to an alternating cycle of constructive and destructive waves.
• this is because constructive waves build up the beach resulting in a steeper profile, which encourages waves to become more destructive. however, with time, the destructive waves more beach material out to sea, forming an offshore bar and reducing the beach’s angle. this encourages low energy waves to deposit sediment onto the beach.
• this is called: NEGATIVE FEEDBACK as the system attempts to maintain dynamic equilibrium

Question 10

dynamic equilibrium is almost impossible to maintain on the coast because

Answer 10

other factors such as wind strength and direction are not constant