why do we have high and low tides?

Question

tides

Answer 1

Here's why we have two high tides and two low tides each day. Think of the earth as a big circle, with the moon as a small circle or a dot way off to the right. Suppose the earth is covered by ocean.

The moon's gravity is related to distance ... the shorter the distance, the greater the gravity. The side of the earth closest to the moon (the right side in our imaginary diagram) experiences the strongest gravity from the moon, and the side farthest from the moon (the left side of the earth in our diagram) experiences the weakest gravity.

The top and bottom of the earth, being an "average" distance from the moon, experience "average" gravity.

Now, the places where gravity is strongest will bulge out from the earth; and by comparison, the places where there's gravity will "sag" inward toward the center of the earth.

Taking this altogether, the sides closest to and farthest from the moon will experience high tides, while the "average" places in the middle will experience low tides.

With these ideas in mind, set the world to spinning. It becomes clear that there will be two high tides and two low tides everywhere each day.

Answer 2

The moon and sun act together or in opposition to cause the tides that we see. Gravitational attraction of the moon and the sun causes the tides but not how most people think. Most people think that the moons gravitational attraction pulls the water on earth towards the moon thereby causing the tides. But if this were THE reason we have tides then we would only have one high tide per day and as you know we have two.

So What Does Cause the Tides?
If the earth we the only heavenly body the gravitational attraction of the earth would be the same everywhere and would be constant. This would result in no tides. However, the sun and moon both exert a gravitational force on the earth. These forces are relatively weak and we aren't sensitive enough to notice. But they are strong enough to alter the gravitational center of the earth.

Look at it this way. If you where at the center of a large mass in space. You would be pulled towards it. If you where to get inside of it and travel to the center you would be pulled equally in every direction. You would then be weightless. This point is the gravitational center of the object we will now call earth. Now since the other object, the moon also pulls on us we would no longer be weightless at the center of the earth, although it would be extremely small the moon would be pulling on us. As we moved toward the moon we would nolonger be at the center of the earths gravitational pull so it would start to pull on us. Once you reach a point where the pull of the earth is now countering the pull of the moon then you would again be wieghtless. This point exist in real life inside the earth closer to the surface than the true center of the earth. You must remember that even though the moons pull on you is small the force excerted on the earth is much larger because the earth is much larger.

The earth and moon both orbit this "center of mass". This orbital motion causes the earth to experience a centrifugal force on the side away from the moon, which forces the ocean in the direction away from the moon! So the centrifugal force forces water to a high tide on the one side of the earth while the gravitational pull of the moon causes a high tide on the other side of the earth. As the earth spins on its axis, a given seaside location will experience a high tide when the moon is at its closest, and then another one about ~12 hours later when it is on the other side of the earth from the moon.

Answer 3

This is due to the gravitational force of the moon. When full moon is on one side of the planet, gravitational force is so intense that causes high tide while on the other side of the planet, there's low tide

Answer 4

It has to do with the moon's gravity, of course, but the key is that the gravity changes with distance. The water on the moon side of the earth is attracted more strongly to the moon than is the solid mass of the earth, which is in turn attracted more strongly than the water on the other side. Thus the tidal effect is proportional, not to the gravity itself, but to its first derivative with respect to distance. Which explains why the sun's effect on the tide exists but is smaller: the sun is so far away that the differential attraction is small even though the sun's mass is huge.

Answer 5

Unless I am completely off the planet it is due to the effects of the moon.

I would have to say that without high and low tides a lot of the smaller water creatures would die and that would then cause the ripple effect righ through the whole chain of sea creatures.

Answer 6

Depending on where you are on earth there are regular patterns, diurnal tides - one high, one low, semidiurnal 2 high of roughly equal height & 2 low of roughly equal depth, semidiurnal mixed, where you get a higher high & lower low, & combinations...
Tidal theory has 2 flavours, equilibrium tidal theory where we study an earth covered with a uniform depth of water -- this simplifies the study of the sun & moon's gravitational effects. The dynamic theory is what an oceanographer would use & takes into account modification by landmass, geometry of basins, earth's rotation etc.
If you want to know more, look into shallow watr wave theory.

Answer 7

The moon has its own gravitations pull and it afters the tidal pattern of our oceans...well it causes the tidal patterns of our waters. Where the moon is = high tide

Answer 8

tides are influenced by the moon's gravity

Answer 9

the gravity of the moons pulls the water across the planet

Answer 10

well, it is because of the gravitational force of the moon acting on the earth. we have it twice daily.