OCEAN WAVES

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OCEAN WAVES TIDES

• A GENERAL OVERVIEW OF FUNDAMENTAL MOTIONS IN THE
  EARTHS OCEANS
• TOM DOWNER
• CHAPARRAL ALTERNATIVE EDUCATION

2
WAVES
Ocean surface waves occur in the upper layer of
the ocean. They result from wind and may travel
thousands of miles before striking land. They
range in size from small ripples to huge 30 to 50
foot swells.
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SURFACE WAVE CREATION

• WAVES ARE CREATED BY WIND.
• AS WIND BLOWS ACROSS THE WATER FRICTION FORCES
  THE WATER ALONG WITH IT.
• WHEN THE WIND CONTINUES TO BLOW THE WAVE HEIGHT
  BUILDS UP.

• WAVE HEIGHT DEPENDS ON 1.THE SPEED OF THE WIND
  2. THE DISTANCE THE WIND BLOWS OVER (Fetch) 3.
  THE LENGTH OF TIME THE WIND BLOWS.
• ONCE WAVES ARE CREATED THEY CAN TRAVEL THOUSANDS
  OF MILES.

Click here to see a simulation of wave creation

• TSUNAMIS ARE CREATED BY WATER DISPLACEMENT LIKE
  RIPPLES FROM A STONE.

4
WAVE MOTION
Unless a wave is breaking the water is not moving
forward.
Only the energy moves forward.
Click here to see a simulation of wave motion
Hold a rope or string a few feet apart and wiggle
the rope a wave moves along the rope but the rope
remains the same .
Waves break when the bottom of the wave drags
along the ocean floor slowing the bottom as the
top overtakes it.
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Wave Anatomy
When a wave bottom strikes a reef or shallow
water the wave height jumps and over the trough.
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TIDES
Tides are the systematic rise and fall of the
oceans level caused by the gravitational pull of
the Moon and Sun.
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Gravitational Pull
Moon The close strong gravity attraction between
the the moon and earth causes the oceans to bulge
outwards directly below and on the opposite side
of earth.
Sun The sun has a smaller effect on tides it can
add to or take away from the moons pull depending
on how they line up.
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Types of Tides
Neap Tides Tides that take place when the pull of
the earth, moon and sun are 90 degrees to the
earth. Neap tides occur during 1st and 3rd
quarter of the lunar cycle. They have small
differences between high and low tides.
Spring Tides Spring tides take place when the
earth, moon and sun are lined up with the earth.
Spring tides occur during Full and New moons of
the lunar cycle. They are much higher and lower
then normal tide.
The Earths rotation causes the tides to rise and
fall each day.
View simulation and explore information about
tides