chapter 8- waves

Question 1

generating force

Answer 1

Responsible for creating a disturbance on the water surface (wind, earthquakes, water displacement) creates ripples or capillary waves.

Question 2

restoring force

Answer 2

Responsible for returning the water suface to an undisturbed state (gravity and surface tension)

Question 3

cats paw

Answer 3

Restoring force - small patches of waves that darken the surface, move quickly, and die out rapidly.

Question 4

Majority of the waves seen on the ocean or lake are..

Answer 4

gravity waves

Question 5

Crest

Answer 5

Part of the wave that is elevated the highest above the undisturbed sea surface (aka equilibrium surface)

Question 6

Trough

Answer 6

Part of the wave that is depressed the lowest below the undisturbed sea surface. It is flatter than the crest.

Question 7

wavelength

Answer 7

Shortest part of the waveform that, if repeated multiple times, will reproduce the wave slope. This distance between 2 wave crests.

Question 8

wave height

Answer 8

Vertical distance from the elevation of the crest to the depth of the trough

Question 9

wave frequency formula

Answer 9

Is equal to one half the wave height (vertical distance from crest to undisturbed water or trough to undisturbed water)

Question 10

wave shape

Answer 10

Equal to the wave height divided by the wavelength.

Question 11

wave period

Answer 11

The time required for the wave crest “A” to reach point “B” from a staionary point.

Question 12

wave frequency

Answer 12

The number of wave crests passing point “A” each second. (The reciprocal of the wave period.)

Question 13

orbit

Answer 13

In waves, the path followed by the water particles affected by the wave motion.

Question 14

progressive wind waves

Answer 14

Wave that moves or progresses in a certain direction.

Question 15

storm center

Answer 15

An area of origin for surface waves generated by the wind; an intense atmospheric low pressure system.

Question 16

forced waves

Answer 16

When waves are being generated, they are forced to increase in size and speed by the continuing input of energy.

Question 17

free waves

Answer 17

Move at speeds controlled by their periods and wavelengths. (tsunami)

Question 18

sorting/dispersion

Answer 18

waves with different lengths and velocities gradually move through and ahead of the shorter, slower waves. (Aka dispersion)

Question 19

wave trains

Answer 19

Progressions of similar or identical waves with approximately the same period and speed

Question 20

swell

Answer 20

Uniform, free waves

Question 21

wave height is controlled by…

Answer 21

Wind speed
Wind duration
Fetch (the distance over water that the wind blows in the same direction)

Question 22

episodic waves

Answer 22

An abnormally high wave that occurs because of a combination of intersecting wave trains, changing depths, and currents.

Question 23

wave steepness

Answer 23

Ratio of wave height to wavelength.

Question 24

speed of waves

Answer 24

The wavelength divided by the period.

Question 25

shallow water wave

Answer 25

Wave with a depth of less than 1/20 of the wavelength. Set water particles in elliptical motion.

Question 26

diffraction

Answer 26

Process that transmits energy laterally along a wave crest.

Question 27

breakers

Answer 27

Sea surface water wave that has become too steep to be stable and collapsed.

Question 28

four types of breakers

Answer 28

1.Plungers -Moderately steep slopes. Crest out runs the rest of the wave, curves over the air below it.(Surfing waves.) 2.Spillers- Very gentle beach slopes. Last longer, they lose energy gradually. 3.Collapsing Breakers- Steep bottom. Wave collapses over lower part of wave w/ little foam & splash. 4. Surging Breakers- Steep slope. Wave steepens & leans forward, but doesn't collapse. Runs up on beach w/out much splash.

Question 29

rip current

Answer 29

Strong surface current flowing seaward from shore; the return movement of water piled up on the shore by waves and wind.

Question 30

internal wave

Answer 30

Wave created below the sea surface at the boundary between two density layers. They are slower than surface waves.

Question 31

standing waves

Answer 31

Do not progress; they rise and fall vertically

Question 32

node

Answer 32

Point of least vertical motion in a standing wave

Question 33

antinode

Answer 33

Portion of standing wave with maximum vertical motion.

Question 34

wave refraction

Answer 34

Most waves approach land obliquely (not parallel to shore). End of wave closest to land slows first, causing wave to bend toward parallelism w/shore.

Question 35

seiches

Answer 35

Standing waves that occur in natural basins. The oscillation of the surface is called seiching.

Question 36

wave reflection

Answer 36

If wave strikes breakwall or steep beach, can reflect back. Angles same as light reflection. Creates chop.

Question 37

swash

Answer 37

Water rushing up beach in direction of wave arrival.

Question 38

backwash

Answer 38

Water flowing back down beach slope to sea.

Question 39

longshore drift/current

Answer 39

caused by swash and backwash. Creates Zig-zag motion of water & sediment along beach. Sand grains move along beach which creates the beach itself. NET transport along beach. Avg. drift ~5-10 m/day depending on wave energy.

Question 40

rip currents

Answer 40

Concentrated areas of backflow into sea. Often channeled by low in offshore bar. Undertow up to 1 m/sec. Get caught in this swim parallel to shore to allude concentrated pull.

Question 41

internal waves

Answer 41

Waves can occur along any surface separating two mediums of different density (eg- air/water). Can get waves along top of pycnocline- can have large height, but move slowly and break, mixing the 2 layers