How does the moon cause tides on earth ?

Question

How does the moon cause tides on earth ?

Answer 1

Because of the moon's gravity.

Answer 2

This is one of the most widely mis-understood phenomena... if not THE most mis-understood.

The gravity of the moon is involved, but not in the way other contributors have said.

The answer is in two parts.  The first is to look at the interaction of the moon and the earth.

Strictly speaking, the moon does not orbit the earth!  It orbits the common centre of gravity shared by the earth and moon together.  Because the moon is about 1/80th the size of the earth, the common centre of gravity is about 75km away from the centre of the earth.  The earth and the moon orbit each other around this radius from the centre of the earth.  

Now consider the earth's rotation around the sun.  As the earth rotates on its axis, there is a pull towards the sun and there is also a pull towards that common centre of gravity between the earth and moon.  Depending on the time of year, Those two forces are acting in the same direction, opposing directions or somewhere in between.  Maximum height tides occur when they are pointing in the same direction. The latitude you are at determines the extent of that combined force of those two pulls.

As the earth rotates, the water at any particular place on earth experiences either a pull dominated by the sun or the centripetal force that balances the sun's pull.  This gives rise to the two daily tides.  The previous force balance modifies the dominant effect of the sun.  

Finally, there is the viscosity of water.  Water does not just flow right round the planet in response to these forces.  It takes time to flow  Therefore it cannot flow very far.  The effect is that water sloshes backwards and forwards in huge basins.  This is why certain places on the earth have very large tides but other places nearby might have small ones.

Answer 3

When,moon comes near to the earth it's gravity pulls the water mass from ocean or sea.When its moves,ets gravity will pull water with it.When it goes farther the gravity becomes low and water falls in cities.

Answer 4

Tides are created because the Earth and the moon are attracted to each other, just like magnets are attracted to each other. The moon tries to pull at anything on the Earth to bring it closer. But, the Earth is able to hold onto everything except the water. Since the water is always moving, the Earth cannot hold onto it, and the moon is able to pull at it. Each day, there are two high tides and two low tides. The ocean is constantly moving from high tide to low tide, and then back to high tide. There is about 12 hours and 25 minutes between the two high tides.

Answer 5

Tides are periodic rises and falls of large bodies of water. Tides are caused by the gravitational interaction between the Earth and the Moon. The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side, since the Earth is also being pulled toward the moon (and away from the water on the far side). Since the earth is rotating while this is happening, two tides occur each day. Isaac Newton was the first person to explain tides scientifically

Answer 6

jessica's right. also, the sun affects tides as well. if both the sun and moon are pulling together at a part of the ocean, you get the highest tides. if they're pulling opposite, you get weaker tides.

Answer 7

The gravitational pull of the moon causes the earth's oceans to bulge. This bulge is the high tide. In fact the moon causes the oceans to bulge in two places, the oceans facing the moon and the oceans facing away from the moon. The moon's gravity has a greater effect on the oceans facing the moon than on the earth itself. This causes the water directly under the moon to bulge. The moon pulls the rocky part of the earth more strongly than the water on the far side. This causes the oceans on the far side of the earth to get left behind and the water bulges there as well.