Learn about the Tides

The tides, are when the waters of the sea, rise and fall, because of the gravitational pull of the moon and the sun. The tides usually happen twice a day. Gravity is what makes everything stay on the earth, but since water is just a liquid, the gravitational pull of the moon and the sun, can actually make the water rise and fall. The moons gravitational pull is just enough to raise the water of the seas, but nothing else.

The moon pulls the sea water up a little bit, that kind of makes a bulge in each side of the earth. This is high tides.

One side of the earths high tides is caused by the moons gravity, and the other side of the earths high tides is caused by the principle of inertia. It is really complicated to explain, but imagine that you are spinning a rope with something fairly heavy on the end of the rope. Imagine that the earth is in the middle of you and the heavy object at the end of the rope. Since you are spinning, you need to lean back to balance out the heavy object at the end of the rope, and your spinning. This is the same with the moon and the rotation of the earth. If the earth is spinning, and the moons gravitational pull is pulling the sea one way, the other side of the earth needs to have the same effect as the moon, but on the completely other side of the earth.

The moon is what mainly causes the tides, but the suns gravitational pull, can very the tides by either making them a little higher than normal, or a little lower than normal. The sun can only affect the tides a little bit, because the sun, is way farther away from the earth than the moon, so the sun can not effect the tides as much as the moon can.

When the sun and the moon are aligned in a straight line, so that they are on-top of each-other, the tides are a little larger than normal, because the suns gravity is helping the moons gravity by pulling the water bulge from the earth, making the tides a little bit bigger than normal. These tides are called spring tides, and they happen on Full, or New moons.

The sun helps the moons gravity enhance the tides just a little bit.

When the sun, and the moon, are at a 90 degree angle from each other, the sun, actually makes the tides a little bit smaller than they would usually be. This is because, the sun, is pulling the earths water towards itself, where the tides would be low usually, but the sun makes the tides smaller where the moons gravity is pulling. This happens on the quarter moons, and this is called neap tides.

The sun, is pulling on the low tide part of the earth, making the moons
effect of high tides, less effective, so the high tides are lower than usual.

The moon rotates around the earth 13 times a year, and this means that every day, the tides will happen twice, once every 12 hours and 25 minutes, (the 25 minutes makes up for the one year added extra to the moons rotation around the earth 13 times a year)


I hope you enjoyed this Learner post, and if you have any questions, feel free to ask!


-August 16, Sunday (blog later today)