wind and waves

Question 1

how are waves created

Answer 1

wind blows over the surface of the sea - friction between wind and sea forms waves - waves follow an orbital movement (tides) - when a wave reaches shallow water the wave is slowed due to friction with the sea bed - the wave spills forward moving sediment forward as swash - it then draws back to sea carrying sediment as backwash

Question 2

what 3 things is wave energy controlled by

Answer 2

the force of the wind and its direction

the duration of the wind

the fetch - longer the fetch the more energy the wave possess

Question 3

features of constructive waves

Answer 3

builds beaches

have a longer wavelength, lower heigh and are less frequent (6-8 per minute)

swash is greater than backwash - add material to beaches - giving slight slope to beach

Question 4

features of destructive waves

Answer 4

have a shorter wavelength - greater height - more frequent (10 - 14 per minute)

backwash is greater than swash - sediment is dragged offshore

creates a steeper beach profile (short term) however flattens as material is dragged backwards

forms shingle ridges at back of the beach