Waves

WAVES

Waves

A wave is a rhythmic movement that carries energy through matter or space caused by the varying speeds of winds.

The crest is the highest point of a wave and a trough is the waves lowest point.

The distance between two adjacent crests equals a wavelength.

The height of a wave is the difference between the crest and the trough.

The amplitude of a wave is half of the waves height.

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FREQUENCY

The number of waves that pass a point in a certain amount of time.

Wave Size

Depends on the strength of the wind and the length of time it blows.

Gentle breeze = ripples

Stronger winds = lager waves

Wave size also depends on the distance over which the wind blows.

Longer distance = Bigger wave

Wave movement Waves makes water appear to move forward, but

unless the wave breaks onto a shore, all water returns close to its original spot after the wave passes.

Only the energy in the wave is moving forward not the water.

When a wave does crash onto a shore that wave is called a breaker. This collapsing of a wave is what propels a surfer back toward the shore.

Tsunamis

Not all waves get their energy from wind.

Some like Tsunamis are caused by earthquakes beneath the ocean floor.

Most common in the pacific Ocean striking Alaska, Hawaii and Japan

Affects on Shore

Longshore DriftRip Current

Longshore Drift

Water washes up the beach at an angle carrying sand grains

Water and sand then run back down the beach Waves slow down and deposit sand on shallow

underwater slope = SANDBAR

RIP CURRENT Sandbar traps water flowing along the shore Some water breaks through the sandbar and flows

back down the sloping ocean bottom. The rush of water the flows back to sea is

= RIP CURRENT

WAVES & BEACH EROSION

Waves shape a beach by eroding the shore in some places and building it up in others.

What protects from Erosion?? Barrier Beaches

Sand Dunes Groins