Tag: ocean water movement

In cold countries, tides bring in saltwater and by their constant motion prevent harbours from becoming icebound. Low-lying areas along the sea-coast which get the seawater during high tides can be used to produce salt by trapping the water.

The rhythmic rise and fall of ocean water twice in a day is called a tide.

The strong gravitational pull exerted by the sun and the moon on the surface of the earth causes the tides.

Seven days after a spring tide, the sun and moon are at right angles to each other. When this happens, the bulge of the ocean caused by the sun partially cancels out the bulge of the ocean caused by the moon. This produces moderate tides known as neap tides, meaning that high tides are a little lower and low tides are a little higher than average. Neap tides occur during the first and third quarter moon, when the moon appears "half full."

Neap tides occur when the Moon and Sun form a right angle with the Earth. In contrast to spring tides, neap tides are the effect of tidal forces canceling each other.

Tides are caused by the moon. The tidal force causes Earth and its water to bulge out on the side closest to the moon and the side farthest from the moon. These bulges of water are high tides. It is because of high tides only that the sea level rises.

Very high tide is caused when the sun, the moon and the earth are almost in the same line. Such high tides are called spring tides. During new moon and full moon the gravitational forces of sun and the moon work together with combined force and thus this spring tide occurs. 

On an average, every place experiences high and low tide a day at an time interval of 12 hours 25 minutes. Since the earth completes its rotation in roughly 24 hours, every place should experience tide after 12 hours but this never happens. Each day tide delayed by 25 minutes because the moon also rotates on its axis while revolving around the earth.