Tide Clocks keep track of the high and low marine tides and are useful for anyone who makes a living on the sea or just enjoys sailing.
About Tides: Tides follow the moon in its apparent motion around the earth. The tides rise and fall twice in the time between two rising moons, about 24 hours and 50 minutes. The time between two rising moons is determined by two motions: (1) the rotation of the earth on it’s axis and (2) the revolution of the moon around the earth. As the earth turns on it’s axis, the moon appears to sweep across the sky once a day. But relative to the sun, the moon revolves around the earth once in about 29 ½ days. Therefore, the moon moves about 12 degrees around the earth each day. Between each lunar rising, the earth makes a complete rotation, and then turns this additional 12 degrees. This extra 12 degree turn takes about 50 minutes.
Tides rise and fall in a cycle that is regulated by the moon’s gravity. When the water is at low tide, it rises gradually for about 6 hours until it reaches high tide. Then it falls gradually for about 6 hours until it is at low tide again.
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