Waves

What is a wave?

A wave is a disturbance that transfers energy through water (or another medium) without transporting the water itself over long distances.

What are the two forces that generate waves?

Waves are generated by a disturbing force (like wind) and a restoring force (like gravity and cohesion of water molecules).

What is wavelength

Wavelength (L) is the distance from one crest to the next crest or from one trough to the next trough.

How is wave height defined?

Wave height (H) is double the amplitude, the distance from the crest to the trough.

What is wave steepness?

Wave steepness is calculated by dividing wave height by wavelength (H/L).

What is Stokes drift?

Stokes drift explains the small forward movement of water itself, despite waves primarily moving energy.

What determines wave speed in deep-water waves?

In deep-water waves, speed is a function of wavelength only; longer wavelength waves move faster.

What determines wave speed in shallow-water waves?

In shallow-water waves, speed is a function of depth only; all waves in shallower water move slower.

What is the fetch in wave development?

Fetch is the uninterrupted distance over which the wind blows without a significant change in direction.

What is the effect of wind speed on wave development?

Wind speed must be faster than the wave crests for energy transfer to continue and generate larger waves.

What is constructive interference in wave motion?

Constructive interference is additive, resulting in waves larger than the original waves.

What is destructive interference in wave motion?

Destructive interference is a cancelling effect, resulting in reduced or no wave.

What is a rogue wave?

A rogue wave is a huge wave resulting in a wave crest higher than the theoretical maximum.

What causes tsunamis?

Tsunamis are caused by the rapid displacement of ocean water due to seismic activity, landslides, or volcanic eruptions.

What is a seiche wave?

A seiche wave is a standing wave in an enclosed or partially enclosed body of water, caused by changes in atmospheric pressure or wind.

What happens to waves as they approach the shore?

Waves change from deep-water waves to shallow-water waves, often resulting in breaking waves (whitecaps).

What are internal waves?

Internal waves form between ocean layers of differing densities.

What is the difference between summer and winter beach conditions?

In summer, gentle waves push sand shoreward, creating wide sandy beaches; in winter, storm waves drag sand offshore, resulting in rocky beaches.

What is the best strategy if caught in a rip current?

Swim parallel to the shore for a short distance before swimming back to shore.

What is wave refraction?

Wave refraction is the bending of waves as they approach shallow water, causing them to change direction.

What is wave diffraction?

Wave diffraction is the spreading of waves as they pass through openings or around obstacles.

What is the significance of wave period?

Wave period (T) is the time it takes for a wave to pass a point in space and is crucial for calculating wave speed.

How does wave energy concentration vary?

Most wave energy is concentrated in wind waves, but large tsunamis can transmit more energy than all wind waves for a brief time.

What is the relationship between wave speed and water depth?

In deep water, wave speed is primarily determined by wavelength; in shallow water, it is determined by depth.

What is the role of gravity in wave formation?

Gravity acts as a restoring force that flattens the water surface after a wave has formed.

What is the impact of wind duration on wave size?

Winds that blow for a longer duration generate larger waves compared to short-duration winds.

What is the significance of wave trains?

Wave trains are groups of waves that travel together, with energy being transferred forward and to the waves behind.

Amplitude

the distance from the still-water line to thecrest or trough

swell

smooth undulation of ocean water caused by wave dispersion

wavelength ___ and amplitude ____ as waves appraoch shore

decreases, increases

breaking waves

lower part of wave is slowed by friction but crest continues moving faster than the wave

tsunami

long-wavelength, shallow-water, progressive wavescaused by the rapid displacement of ocean water

rip current

a rush of water that flows rapidly back to sea through a narrow opening