Lecture 6- Ocean Waves

Question 1

wavelength

Answer 1

crest to crest distance (top of wave)

Question 2

speed

Answer 2

distance crest travels per unit time

Question 3

period

Answer 3

time it takes a crest to travel one wavelength

Question 4

freqency

Answer 4

number of crests passing a fixed location per time

Question 5

constructive interference

Answer 5

occurs when two waves combine to make a wave with higher amplitude

Question 6

destructive interference

Answer 6

occurs when two waves combine to make a wave with lower amplitude (cancel each other out)

Question 7

What do waves propagate?

Answer 7

energy not mass

Question 8

What determines wave speed?

Answer 8

wavelength and bottom depth

Question 9

waves with longer wavelenth

Answer 9

travel faster than waves with shorter wavelength

Question 10

waves traveling in deep water

Answer 10

travel faster than waves in shallow water

Question 11

in very deep water, wave speed is aa function of – only

Answer 11

wavelength

Question 12

in very shallow water, wave speed depends on — only

Answer 12

bottom depth

Question 13

deep water waves

Answer 13

• bottom depth is more than 1/2 wavelength
• speed is a function of wavelength only
• longer wavelengths travel faster

Question 14

shallow water waves

Answer 14

• bottom depth is less than 1/2 wavelength
• speed is a function of bottom depth only
• waves in shallow water travel slower

Question 15

wave dispersion

Answer 15

• self sorting of deep water waves leaving a storm region

- occurs because longer wavelengths travel faster

Question 16

wave refraction

Answer 16

bending of shallow water wave front due to change in bottom depth

Question 17

longshore sediment transport

Answer 17

occurs when waves strike the beach at an angle

Question 18

breaking waves

Answer 18

waves slow down as they feel the bottom depth but the waves behind are still traveling quickly so it causes crowding

Question 19

summer beach conditions

Answer 19

gentle waves push offshore sandbar shoreward to create wide and gently sloping sandy beach

Question 20

winter beach conditions

Answer 20

storm waves push sand off the beach into offshore sandbar resulting in rocky winter beach

Question 21

rip currents

Answer 21

• accelerated jets of water

- narrow, seldom wider than 10 meters

Question 22

What should you do if you’re caught in rip current?

Answer 22

swim parallel to shore for 10-20 meters

Question 23

wave height of wind generated waves depends on

Answer 23

• wind speed
• duration of wind event
• fetch

Question 24

wind speed

Answer 24

sets the upper possible limit on wave height

Question 25

duration of wind event

Answer 25

modulates the upper possible limit on wave height

Question 26

fetch

Answer 26

• depends on size of storm

- distance over which wind can blow without obstruction

Question 27

internal waves

Answer 27

• travel along density discontinuities in the ocean interior
• atmosphere is low density fluid, ocean is high density
• slow motion