The Magic of the Ocean and the Moon

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Original artwork by the author

by Bree Gerold, AP Physics 1 Student

Perhaps it is the oh so exciting thought of spring break quickly approaching, or maybe it is my constant fascination with the ocean, but recently I have found myself in a daydream about the beach.  Ever since I was a little girl, I have always been fascinated by the rising and the falling of the ocean waves.  I remember that it always baffled me how the ocean could get bigger, then shrink back up again, like clockwork.  I didn’t understand it.  I didn’t understand gravity, I didn’t understand physics.  Perhaps there is a bit of magic to that; to the complete innocence of a child who is so easily mesmerized by something as simple as the ocean’s tides.  That’s what it was to me.  It was magic.

Now as a senior in high school, I have been through many physics classes and have managed to gain at least enough knowledge to understand how the moon and the ocean create the tides.  Ocean tides are created by combining the gravitational pull of the moon and the sun, combined with the rotation of the earth. The moon’s gravitational pull is stronger than the sun’s which makes it the most important factor in creating tides. The tides are really long-period waves that appear as the rise and fall of the sea as they reach the coastline. High tide is the crest of the long-period wave and low tide is the trough of the long-period wave. The earth rotates on its axis once every 24 hours and the moon rotates around the earth once every 28 days. The moon pulls upward on the ocean while the earth pulls down. This causes tidal movement. The tidal troughs are separated by about 12 hours. Because the moon rotates around the earth, it’s not in the same place at the same time every day.  So the high and low tide times change every day by about 50 minutes.

Even now, after understanding the physics of it all, it still seems like magic.  It is magical how the moon, that is so far away, can have such a compelling effect on the little girl I once was.

Works Cited

“Ten Cool Facts About Ocean Tides.” Oceans52. WordPress, 05 Apr. 2012. Web. 06 Mar. 2016.

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