Tides

Tides By: Olivia Gillinger

The word tides refers to the rise and fall of the sea level each day. The gravitational pulls between the sun and the

moon is what causes the sea levels to rise and fall. The gravitational pull creates a giant wave. This wave is only

about one or two meters high, but its length is thousands of kilometers long. As the crest, or the top of the wave, gets

closer and closer to the shore, sea level rises. This is known as high tide.

The moon revolves around the Earth about twelve degrees everyday. This is about one rotation every month. This

rotation of the moon is in the same direction of the Earth. When the earth has completed one rotation or on day has

elapsed, the moon has rotated twelve degrees. This causes the moon to need an extra fifty minutes to line up to the

same spots on the Earth. This means that the tidal day will be fifty minutes longer or 24 hours and 50 minutes. This

causes the high tides and the low tides to come fifty minutes later each day.

The sun can also cause a gravitational changes to the tides.This gravitational pull, by the sun, can cause spring tides

and neap tides. When the Earth, the moon, and the sun are lined up in a straight line, it causes a spring tide. During

spring tides, the high tides are higher than they usually are and the low tides are lower than they usually are. When the Earth, moon,and the sun

are lined up in a right angle, it causes a neap tide. During a neap tide, the gravitational pull is shifting the water, this causes the high tides to be

lower than usual and the low tides will be higher than usual.