# Tides

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```					Name: ___________________________________              Period: ______________       8th grade science

Lunar Cycles and Tides
Introduction:
In most parts of the world, high and low tides amount to a difference of less than a meter, but can
differ as much as tens of meters in some parts of the world. Tides are important in navigation, to
sportsmen, marine life, and people living in low lying or beachfront areas.

Tides are affected by many things including nearby objects in space that have mass such as the moon,
the sun, and even Jupiter. Tides are also influenced by the topography of the planet earth, which
affects the way water can flow around its irregular landforms as it swells in response to the moon’s
gravitational pull.

Objective:
By the end of this lesson you will be able to identify a rhythmic pattern of tides and moon phases and
analyze their relationship.

Procedure:
1. Go to the link titled                                   2. Click on the picture.
_tide.swf                                               4. Go to “Tide Simulator.”

Answer the following questions as you move sequentially through the web quest.

1. Is the Earth a solid object? Explain.

2. On the first animation, slow down the speed and click the box that says “Show Spring/Neap Tides.”
What causes there to be two kinds of tides?

3. Why are there TWO bulges of water on opposite sides of the Earth during tides?

4. If the Earth had more than one moon, how would the tides be affected?

5. Why does the water on Earth bulge more than the Earth itself?

6. Why is the side of the Earth closest to the moon pulled more by the moon’s gravity than the far side
of the earth?

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Name: ___________________________________                  Period: ______________         8th grade science

Next Procedure: Using Real Tidal Data from Monterey California
1. Follow directions 1-3 from Day 1.
2. Go to “Tide Level Observer.”
3. Clicking on each calendar day will give you the moon phase water level in meters.
4. Follow the directions on the “Lunar and Tidal Cycles Data Table” below.

Tides and Lunar Cycles Data Table
Fill in the sea level measurement and draw in the moon phase for the following given dates. Every 2nd or 3rd date
is blank. Choose your own date here and make a prediction (by filling in the chart) about the sea level and moon
phase. Make sure the actual dates and the predicted dates are in chronological order.

Plot the sea levels for each date on the Tides and Lunar Cycles Graph. Each plot should be a sphere with the
appropriate moon phase drawn in it.

Date of             Sea Level          Moon Phase             Date of         Sea Level         Moon Phase
Observation            meters             (Draw)              Observation        meters            (Draw)

January 2                                                    February 3

January 4

February 11

January 12

February 16

January 18                                                  February 18

January 19

February 25

January 27

March 2

January 31                                                    March 3

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Name: ___________________________________             Period: ______________       8th grade science

After you have graphed your tides and moon phases, answer the following questions.

1. Where does the full moon and new moon fall on the tidal cycle?

2. Where is the moon relative to the Earth and Sun (for instance in-line or at a right angle) during
a. high tide?

b. Low tide?

3. Would there be any tides if there were no moon? Explain your answer.

4. Why do all high tides differ in height? Name some contributing factors.

5. Some estimates predict that due to global climate change, sea levels may rise by 0.88 meters in
the next 100 years. Would this beach front community be safe if the sea levels were to rise that

BONUS QUESTION

6. It is estimated that when the moon is 10% closer to the earth that tides increase in height by
20%. Would this beach front community be safe if the moon were 20% closer to the earth than
it is right now? The community has been built 2.4 meters above sea level. Explain your answer

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Name: ___________________________________   Period: ______________   8th grade science

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