tides and moon

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   How are Tides
    related to the
Phases of the Moon?


Tide Notes: Travel around the room to complete this page.
Tides are a result of the gravitational interaction between what 3 solar system objects?

       1. _______________________________________________
       2. _______________________________________________
       3. _______________________________________________

In your own words, explain how the moon affects ocean tides:





Label the Sun, Moon, and Earth and draw the appropriate tidal bulges in the two diagrams below. Then
identify which diagram show a spring tide and which diagram shows a neap tide:

Why is Isaac Newton on the wall today? ______________________________________________________


Why are there 2 tides per day? _______________________________________________________________


What phases of the moon result in spring tides? _________________________ and ____________________

What phases of the moon result in neap tides? _________________________ and ____________________

Why is the time for high and low tides different every day? _______________________________________


On Line Tide Activity Go to a computer and open the web page
http://www.glencoe.com/sites/common_assets/science/virtual_labs/ES17/ES17.html. Complete the “On Line
Tide Activity” worksheet.

Read the information on the left hand side of the page, scrolling as necessary. Answer these questions:

   1. According to the web page, what causes high tide?
   2. What causes low tide?

Click one of the four circles around the Earth.

   3. Choose a location and record it here: _____________________________
   4. Observe the water level at 12:00 am (that’s midnight). Click the hourglass to begin the day’s tide cycle.
      Observe the rise and fall of the water level for six hours of the tide cycle.
   5. Read the measurement after the water level has reached the first low or high tide of the day. Record it
      by clicking the up and down arrows to scroll through the measurements.
   6. Click the hourglass again and collect data for the next six hours of the tide cycle.
   7. Click the hourglass again and collect data for the next six hours of the tide cycle.
   8. Click the hourglass again and collect data for the next six hours of the tide cycle.
   9. Click the “CHECK” button. If a measurement is recorded incorrectly, it will be highlighted yellow. Click
      the panel with the highlighted measurement and examine the water level. Select another

Record your data here:

Phase of the moon             Date                     Highest low tide (record     Highest high tide (record
                                                       the higher of the 2 low      the higher of the 2 high
                                                       tides)                       tides)
New Moon

First Quarter

Full Moon

Last Quarter

Now, graph your data as described below:

   1. The title of your graph should be “Tides at _________” using the name of the location you examined in
      the blank.
   2. The label for your x-axis is “date” and the label for your y-axis is “height (m).”
   3. There should be TWO line graphs, one for HIGH tides (please indicate in a key what color line that is)
      and one for LOW tides (also please identify it in your key).
   4. Label the points of the graph with the name of the phase of the moon.

After studying your graph of tide range data write a simple hypothesis which
explains the relationship between tide range and phase of the moon.

If you were living ten thousand years ago, perhaps as a member of a Chumash
village, how might you be able to predict the best day of the month to collect
shellfish from the low tide zone at the beach? Explain.

D Day – The Science and Technology of WWII

Introduction: The D-Day invasion of June 6, 1944, has been called the climactic battle of World War
II. It was probably the most carefully planned and executed military operation in history. It consisted
of a combined amphibious and aerial assault across the English Channel against the beaches of
France, which had been occupied be the German Nazis since 1940. The Supreme Commander of
Allied forces was American general (and later president) Dwight D. Eisenhower. In addition to
numerous political and military advisers, Eisenhower was guided in his choice of an invasion time and
date by a team of astronomers and meteorologists. Why was their advice important? The Allied
invasion was scheduled to begin by an aerial attack by paratroopers and glider-borne troops whose
job it would be to land to the rear of the beaches, disrupt German communications and to seize roads
and bridges to prevent a German counter attack. This air attack was scheduled to begin at about
midnight on the night before the beach landings, which were scheduled to begin at the first light of

   1. Why was the moon important to the Allied invasion plan? Why would the use of artificial
      lighting, like flashlights, be dangerous for the paratroopers?

   2. In order to be useful to the Allies, on the night of the invasion, by what time should the moon
      be high in the sky?

   3. During the times referred to in questions 2 and 3, in order to provide the most possible light to
      the paratroopers, what phase should the moon be in?

   4. Would the night of a new moon be a good night to begin the invasion? Why or why not?

   5. On the night of a full moon, where is the moon at sunset?

Determining the best night for the invasion - By now you are an expert on lunar phases and their
timing. You are ready to advise General Eisenhower of the best night to launch the aerial attack that
will precede the landings at dawn on the beaches. General Eisenhower has advised you that the
soonest date of complete readiness of the invasion force is Sunday, August 1*. You know that on
that night, there will be a waxing first quarter moon. Carefully consult your information and determine
what advice you will give to the general. (*You probably know that the D-Day invasion was actually
on June 6, 1944, not in August. )

                      Your advice to the general:

                      The aerial attack should begin at midnight, on (date)

                      ____________ , followed by beach landings at dawn the next
                      morning .

                      Your reasons for giving the general this advice are as follows:

The Earth’s ocean tides are
a result of variations in
gravitational attraction
between the Earth, the
Moon, and the Sun.

The Moon produces two tidal
‘bulges’ on the Earth.
 1. Due to strong gravitational
  attraction, the sea is drawn
  towards the Moon at the location
  on the Earth closest to the Moon.
 2. Another tidal “bulge” occurs
  simultaneously on the opposite
  side of the Earth, pulling away
  from the Moon.

Tides are periodic rises and falls of large bodies of
water. 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
(1642 -1727)
was the first person to
explain tides scientifically.
His explanation of the tides
(and many other
phenomena) was published
in 1686.

During each ‘tidal period,’
most of the Earth’s surface
experiences two tidal
crests (high tides) and two
tidal troughs (low tides).

Some areas of the Earth
experience only one high
and one low tide per day.
This is called a diurnal tide.

The Sun also influences the
Earth’s tides.
When the Moon, the Earth,
and the Sun are in a straight
line, the pull of the Sun and the
Moon act together to create
higher high tides and lower low
tides, called spring tides.
These tides occur every 14-15
days, during full and new

Spring tides are especially strong tides (they
do not have anything to do with the season
Spring). They occur when the Earth,
the Sun, and the Moon are in a line. The
gravitational forces of the Moon and the
Sun both contribute to the tides. Spring
tides occur during the full moon and the
new moon.

When the moon, the Earth,
and the Sun are at right
angles to each other, neap
tides are formed. Neap
tides occur during the first
and last quarter of the
Moon, and consist of lower
than normal high tides and
higher than normal low

Neap tides are especially weak tides.
They occur when the gravitational
forces of the Moon and the Sun are
perpendicular to one another (with
respect to the Earth). Neap tides
occur during quarter moons.

Spring tides happen
when the sun and
moon are on the
same side of the
earth (New Moon) or
when the sun and
moon are on opposite
sides of the earth
(Full Moon).

When the Moon is at first
quarter or last quarter
phase (meaning that it is
located at right angles to
the Earth-Sun line), the
Sun and Moon interfere
with each other in
producing tidal bulges
and tides are generally
weaker; these are called
neap tides.

Spring tides
and neap tide
levels are
about 20%
higher or
lower than

   Since the moon
    moves around the
    Earth, it is not always
    in the same place at
    the same time each
    day. So, each day, the
    times for high and
    low tides change by
    50 minutes.

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