wave terminology

Question 1

crest

Answer 1

highest part of the wave

Question 2

trough

Answer 2

lowest part of the wave

Question 3

wave height

Answer 3

vertical distance between the crest and the trough

Question 4

wavelength

Answer 4

distance between two consecutive crests or troughs

Question 5

wave frequency

Answer 5

number of wave crests or troughs that pass a fixed point in one second

Question 6

Movement of waves

Answer 6

• Water particles move in an orbit, this motion decreases with depth in deep water.
• An object that’s in the sea will move in orbit and almost return to its original position
• In the open sea, the motion of waves is transmitted by the circular motion of individual water molecules as there is no frictional drag with the ocean floor
• As the waves approach the land and the depth of water decreases to half its wavelength, the circular motion of the water, slowed down by increased friction between the waves and the shallow seabed, becomes elliptical and the base of the waves start to slow down.
• As the waves slow down, waves behind them push them, causing an increase in the wave height.
• The crests of the waves are then thrown forward when the waves become too steep. Thus, they collapse and break, and develop into white foams after trapping air.
• When energy within a wave is released on the coast, it breaks down on the rocks along the coastline into smaller particles, which are then carried by longshore drift to other parts of the coast (eroded)

Question 7

Waves approaching shore

Answer 7

Wavelength decreases
Wave height increases
Speed decreases
Waves “fall over” (breakers)