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TUESDAY SEPTEMBER 19 - WAVES IN DEEP AND SHALLOW WATER
Waves behave differently depending on whether they're in the open sea or near
Out in deep water, the wave shape moves, but each particle of water returns
nearly to its starting position once the wave passes. To see how this works,
imagine a giant cork floating in the deep ocean.
As a wave goes by, the cork
bobs up and down and sways from side to side, but actually doesn't move much
from where it started. The wind does drag the water a bit, and that's what creates
ocean currents such as the Gulf Stream.
The behavior of a wave changes as it approaches the shore.
Once in shallower
water, the wave feels the bottom. It slows down, its height increases, and its
front steepens. Eventually, the wave collapses, or "breaks," creating the
turbulent water we call surf. Almost all the energy that originally went into
creating the waves is dissipated in the surf. That energy powers erosion and
sets sand and sediment in motion.