Here is a bit of explanation from
http://library.thinkquest.org/05aug/00769/gravity/gravity2.htm
...
The gravity of the moon tugs water towards the moon where it is closest to the earth. If your are on the place where the moon is closest to the earth it is high tide. Later on the day the moon astronaut and the earth turn and the gravity becomes less, and it is low tide.The moon has less mass, so the gravity on the moon is less. That is why astronauts can jump so high on the moon.
What causes high tide and low tide? Why are there two tides each day?
The following diagram shows how the moon causes tides on Earth:
In this diagram, you can see that the moon's gravitational force pulls on water in the oceans so that there are "bulges" in the ocean on both sides of the planet. The moon pulls water toward it, and this causes the bulge toward the moon. The bulge on the side of the Earth opposite the moon is caused by the moon "pulling the Earth away" from the water on that side.
If you are on the coast and the moon is directly overhead, you should experience a high tide. If the moon is directly overhead on the opposite side of the planet, you should also experience a high tide.
During the day, the Earth rotates 180 degrees in 12 hours. The moon, meanwhile, rotates 6 degrees around the earth in 12 hours. The twin bulges and the moon's rotation mean that any given coastal city experiences a high tide every 12 hours and 25 minutes or so.
Quote(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fstatic.howstuffworks.com%2Fgif%2Ftides.gif&hash=e682ef9dc7cac1bee8041e8f3c29e178)In this diagram, you can see that the moon's gravitational force pulls on water in the oceans so that there are "bulges" in the ocean on both sides of the planet. The moon pulls water toward it, and this causes the bulge toward the moon. The bulge on the side of the Earth opposite the moon is caused by the moon "pulling the Earth away" from the water on that side.
That makes no sense it would pull the water on the other side to. If that were correct you would only have one high tide aday!
QuoteIf you are on the coast and the moon is directly overhead, you should experience a high tide. If the moon is directly overhead on the opposite side of the planet, you should also experience a high tide.
During the day, the Earth rotates 180 degrees in 12 hours. The moon, meanwhile, rotates 6 degrees around the earth in 12 hours. The twin bulges and the moon's rotation mean that any given coastal city experiences a high tide every 12 hours and 25 minutes or so.
Sorry I do not except that arguement if the gravity pulls the earth it would pull the water to, so the water on the other side would not rise, it would be flat. I do not except that theory!
Quote(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fstatic.howstuffworks.com%2Fgif%2Ftides.gif&hash=e682ef9dc7cac1bee8041e8f3c29e178)In this diagram, you can see that the moon's gravitational force pulls on water in the oceans so that there are "bulges" in the ocean on both sides of the planet. The moon pulls water toward it, and this causes the bulge toward the moon. The bulge on the side of the Earth opposite the moon is caused by the moon "pulling the Earth away" from the water on that side.
That makes no sense it would pull the water on the other side to. If that were correct you would only have one high tide aday!
QuoteIf you are on the coast and the moon is directly overhead, you should experience a high tide. If the moon is directly overhead on the opposite side of the planet, you should also experience a high tide.
During the day, the Earth rotates 180 degrees in 12 hours. The moon, meanwhile, rotates 6 degrees around the earth in 12 hours. The twin bulges and the moon's rotation mean that any given coastal city experiences a high tide every 12 hours and 25 minutes or so.
Sorry I do not except that argument if the gravity pulls the earth it would pull the water to, so the water on the other side would not rise, it would be flat. I do not except that theory!
I have to say that I understand your consternation.
I can understand that since the far side of the Earth is further away from the moon that the centre of the Earth, so the gravitational pull on the far side of the Earth will be slightly less than on the core of the Earth.
On the other hand, the moon is 16 Earth radii away from the moon, so the difference in gravitational pull should only be slight. Against that is the very large difference between the mass of the Earth and the mass of the water resting upon it, and maybe more significantly, the substantial difference in stiffness (the body of the Earth, while still having some elasticity, is certainly not a liquid). Thus, for the same force, the water should be able to respond more quickly, and to a greater extent, than the main body of the Earth, and thus even allowing for the slight difference in gravitational force applied to them respectively, I find it difficult to see that the Earth would move more than the water on the far side of the Earth.
I had always (maybe erroneously) assumed that the opposite tide was due more to the water rebounding (maybe some resonant effect) than direct gravitational force.
Basically the earth which we can see is made out of two substances water and solid and the two react to the pull of the moon by different amounts.
As the moon circles the earth its gravity moves the earth backwards and forwards away from and towards the sun as it does the water on the other side of the earth furthest away from the moon being a fluid reacts to this movement slower than the solid mass causing a tide .
Water being a fluid has a more pronounced reaction to the moon gravity than the solid mass and therefore on the side nearest to the moon it bulges which gives us a tide. But at the same time the solid mass of the earth is also being pulled towards the moon . but the water on the other side being a fluid doesn't react as quickly as the solid to the tooing on throwing of the earth and is sort of left behind which causes it to bulge which causes a tide
I THINK THATS RIGHT
Actually i got it sort of of wrong as its centrifugal force which causes the tide on the other side [:)]
Rather than the water being left behind the earths rotation is pushing the water in the opposite direction to the pull off the moon and the centrifugal force created causes it to bulge
THERE HAS GOT TO BE SOMETHING ON THE WEB.
No i learnt this one a long time ago and i may not be able to remember it 100 but on the moon side the tide is caused by gravity ,on the other side gravity from the moon isnt strong enough to dictate and it is caused by centrifugal force and is caused by the earth rotating around the common centre of gravity between the earth and the moon
THERE HAS GOT TO BE SOMETHING ON THE WEB.
At the same time, an Earth tide and an ocean tide form on the opposite side of the Earth, directly away from the Moon. This second bulge forms as follows (focusing on the ocean tide alone, for clarity): The Moon and the Earth, like all pairs of bodies orbiting each other in space, actually orbit around their common center of mass (that is, the point where, if their individual centers were attached to opposite ends of a rigid stick, the stick could be suspended from a string and remain in balance).
In the case of the Earth-Moon system, the common center of mass happens to be inside Earth, about 1068 miles (663 km) beneath the surface along a line connecting the center of the Earth to the center of the Moon. As the Earth and Moon revolve around this point like dancers spinning with linked hands, all points on both bodies experience a centrifugal force. This centrifugal force has the same magnitude and direction at every point on and in the Earth (i.e., away from the Moon parallel to a line connecting the center of the Earth to the center of the Moon). Where Earth's surface is at any angle other than 90° to the line connecting the center of the Earth to the center of the Moon, water experiences a horizontal component of this centrifugal force. On the half of Earth's surface facing away from the Moon, this horizontal force overcomes the pull of the Moon's gravity and causes water to flow over the Earth's surface to a point on the side of the Earth directly opposite the Moon-facing tidal bulge. A second tidal bulge thus form on the side of the Earth facing directly away from the Moon. This bulge is slightly smaller than the Moon-facing bulge because the imbalance between the Moon's gravitation and centrifugal force is smaller at this point. (The Moon is closer to the Moon-facing bulge, making its gravitation stronger there, whereas the centrifugal force considered here is the same everywhere on the Earth.) The larger, Moon-facing tide is termed the direct tide; the tide on the opposite side of the Earth is termed the opposite tide.