Ocean Motion: Wave Action

Terms in this set (27)

What is a wave?
A wave is the movement of energy through a body of water.
Where do waves start?
Waves start in the open ocean.
What does wind have to do with waves?
Wind is usually the source of energy for a wave.
How is wind a source of energy for a wave?
When wind blows across the surface of the open ocean, it transmits its energy into the water.
How is wave size affected by the wind?
How strong the wind is and how long the wind blows across the water are both contributing factors to a wave's size.
What is moving in a wave?
The energy transmitted to the water is the thing that's moving.
Does water move in deep water?
Water doesn't move in deep water. At a certain point of depth, the water in an ocean doesn't move.
In a wave, how does water move?
Water moves in a circular motion in a wave. As a wave passes, water molecules go forward and down and them back to where they started. Deeper down, the circular motions are smaller until the water doesn't move at all.
What is the crest?
The crest is the highest point of a wave.
What is the trough
The trough is the lowest part of a wave.
What is wavelength?
Wave length is the horizontal distance between crests.
What is the wave height?
The wave hight is the vertical distance between the crest and the trough.
What are beakers?
Beakers are white capped waves.
How do beakers travel in the open ocean?
Beakers travel in the open ocean in long, low-lying waves called swells.
What happens to a wave when it reaches the shore?
As the wave comes near the shore, the ocean floor starts to slope upward towards the beach (the slope is called the continental shelf). The ocean floor causes friction on the wave and the wave length gets shorter and the wave hight increases.
What is undertow?
Undertow is when the water from a wave is going back to sea and is pulling. Undertow can carry sand, shells, and seaweed away from the beach. In some areas it can be hazardous.
What is a tsunami caused by?
A tsunami is caused by an underwater earthquake.
How does an underwater earthquake start a tsunami?
An underwater earthquake sends out pulses of massive energy into the water.
How does a tsunami travel in the open ocean?
Tsunamis have long wavelengths of 200 kilometers or more and have a wave height of less than a meter.
What happens when a tsunami reaches the shore?
The same thing that happens to a regular wave but since the tsunami was caused by more energy it becomes much higher than a regular wave.
What do scientists do to be prepared for tsunamis?
Scientists monitor the ocean floor for earthquakes that might lead to tsunamis.
What is longshore drift?
Longshore drift is when wave comes into the shore, they come in at an angle and carry sand grains.
What is rip current?
Rip current is the current going back to sea from a break in a sand bar. Rip currents flow rapidly back to the sea from the break in a sand bar and are dangerous to swimmers.
What affect does the waves have on the shore?
Waves erode the shore.
Barrier Beaches
Natural landforms that protect the shore from erosion. Beaches like this are usually separated from the mainland by a lagoon.
Sand Dunes
Another kind of natural landform that helps protect beaches from erosion. They are hills of windblown sand. They are held together by roots of grass and other plants.
Groins
Man-made structure made to stop erosion of beaches. On one side of these structures, it protects the shore from erosion but on the other side erosion is sped up.
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