Science project idea on the physics of the moon.
Physics of the Moon Science Project Idea
 Why the moon does not fall to the earth. You have probably wondered why, if the earth and moon are pulling each other, they do not come together just as we found that the rubber band pulled the two marbles together. In order to understand this, we must know that the moon revolves around the earth once in twenty-eight days. This is the explanation of the fact that the moon rises about one hour later every night. If the moon occupied continuously the same relative position to the earth, it would rise at the same time every night. What would be the time between high tides? What is the time between high or low tides?
The way in which the revolution of the moon around the earth prevents it from falling to the earth is illustrated by many very common happenings. What happens when you swing in a vertical circle a pail containing water? What happens to the water on a grindstone, when it is turned rapidly? What happens to an automobile if it attempts to turn a corner too rapidly? What is the advantage of having a circular running track “banked”? Wet clothes are dried by putting them into a large, perforated, metal cylinder and rotating the cylinder rapidly. If you are familiar with milk separators, explain how the milk is separated from the cream.
 All of these observations, showing that rotating bodies tend to fly away from the center around which the body is turning, are illustrations of the fact, that bodies in motion tend to remain in motion in a straight line. They are illustrations of a law stated by Sir Isaac Newton, known as Newton 's first law of motion: “Every body continues in its state of rest or of uniform motion in a straight line, except in so far as it is compelled by force to change that state.” Give other illustrations of the law.
For every body turning around a center there must be two forces ; one drawing it toward the center, called the centripetal force (center-seeking force) ; and one drawing it away from the center, called the centrifugal force. The moon revolves around the earth once in every twenty-eight days. As the moon is 240,000 miles from the earth, you can easily calculate its velocity. Because of this motion what does the moon tend to do? What prevents it? In your own language explain why the moon is not drawn to the earth or does not fly off into space. You will recall that in discussing the cause of the tide on the side of the earth away from the moon reference was made to another force in addition to the difference of the pull of gravitation upon the solid earth and the liquid ocean. This force we can now understand. The moon and earth are held together by the force of gravitation very much as a large man and a small boy might hold themselves together by locking their hands together.
If, while holding hands in this way, the man should swing the boy around, not only would the boy tend to swing in as large a circle as possible, but the coat tails of the man also would tend to fly out because of the centrifugal force. In the same way the water on the side of the earth away from the moon tends to heap up because of this centrifugal force.  There remains yet one problem concerning tides which we decided needed solution: Why, at times, there are especially high tides.
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