Sharon Lynch, age 12, of Tucson, Arizona, for her question:

 Does the moon really make the tides?

The moon really does cause the tides. It pulls at the earth with its force of gravity and the ocean waters mount up into high tides. The spot affected is directly under the moon. This spot becomes a circle because the earth is rotating on its axis. There is a slight lag after the moon passes directly overhead. The crest of the high tide follows the moon around and around the earth.

Most of our planet is covered with ocean water. High tide on one side of the earth effects the oceans all over the world. The mountain of high water is followed by a trough, a low tide. Another mountain of high water piles up on the opposite side of the world with this trough of low water between.

High tide, low tide, high tide and low tide follows each other around and around the world. That is, you get two high tides and two low tides on your favorite beach every day.