Transcript Tides

The Tidal Ecosystem
1. What causes the oceans to
bulge out in the direction
of the moon?
2. What would happen to the
water on the earth if the
moon disappeared?
WHAT CAUSES THE TIDES?
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Tides are caused by the gravitational interaction between the Earth and the
Moon.
The gravitational attraction of the moon causes the oceans to bulge out in the
direction of the moon.
Another bulge occurs on the opposite side, since the Earth is also being pulled
toward the moon (and away from the water on the far side).
Since the earth is rotating while this is happening, two tides occur each day.
Isaac Newton was the first person to explain tides scientifically.
Tides
3. How many high tides are there in a
day?
4. What is happening to the water
between high tide and low tide?
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The sun and the moon
move in cycles affecting
the flow and ebb of the
tides.
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Here in the Pacific, we
have two high and low
tides of unequal heights
each day.
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Between each high and
low tide there is a time
difference of
approximately six
hours.
Tide Zones
•Tidepools, which are exposed
at low tide, occur within a small
strip of land known as the
intertidal zone.
•Sandwiched between the shore
and the ocean, tidepools are
extraordinary, teeming with
hundreds of marine organisms.
•In the picture: Notice that
some of the sand is completely
under the waves, some is wet,
some is drying out, and some is
dry.
5. How do you think the tide zones at a beach
can be found? (think about the picture…)
6. Which zone is
underwater most of
the time?
7. Which one is the
driest tide zone?
8. Are there actual lines
that separate the
zones on the beach?
9. Are the animals the
same in all tide
zones? (Look at the
picture.)
10. Give two ways that
you could tell the tide
zones apart if you
were at the beach….
11.
•Draw this zone diagram
(you can leave out the
organisms. Just draw
the rock.) Leave space
to write things.
•Label each zone
•Go back through slides
13-44 of yesterday’s
assignment. Write the
name of the organism in
the appropriate zone or
zones.