What causes the movement of tides?

Answer 1

Gravity. But not the gravity of the earth. It's moon gravity. The gravity of the moon has enough tug to slosh our earthly oceans around (tides) and of course, since the atmosphere is lighter than the oceans, moon gravity surely roils the atmosphere too. Some scientists in India who research these things, say moon gravity also supplies enough pull on the crust of the earth to trigger earthquakes.

Answer 2

To people who are using this for homework the short answer is

The moon & the sun cause tides.

Over the years people have used several different ideas to explain the tides. Some of them are presented here by different contributors.First Answer This uses the idea of centrifugal force, which is only applicable in a rotating frame of reference, and which many people call a 'fictitious force'.

Tide-generating forces (TGF) are a result of the gravitational attraction between the earth, the sun, and the moon and the centrifugal force due to the relative motions of the moon around the earth, and the earth around the sun. While these forces exactly balance on average, the local mismatch at the earth's surface creates a horizontal force directed towards the surface points closest and farthest from the moon (the "lunar" TGF) and the sun (the "solar" TGF).

This force, because of inertia and friction, lags behind these positions slightly, so the high tides do not occur directly 'below' and 'opposite' the moon and sun.

Second Answer

The gravitational effects of the Moon, and to a lesser extent the sun.

However, The water does NOT rise because of the Moon's gravity pulling on the water... that would not explain why the water on the opposite side of the earth ALSO rises.

To be more precise... It's not the gravity itself, it's the Inertial effects of orbital mechanics in a gravitationally bound orbit.

Tides are caused by the fact that any orbit is based upon the center of gravity of that object, and yet objects can be large enough to extend both inside and outside the orbital path dictated by their center of mass.

for example:

When a long thin object, such as a rocket booster, is in an orbit long enough, without artificial stabilization, it will naturally tend to orient is long axis roughly radial to its orbit.

This is because of tidal tension. The end of the rocket nearest the earth is in a lower orbit... and the further end is in a higher orbit. But both ends are orbiting at the same velocity as the rocket's center of gravity...

The lower end is moving a little too slowly for that lower orbit.. and the higher end is moving a little too fast for its orbit.

Thus the high end experiences negative gravity... as its angular momentum creates an inertial component accelerating inward. And the low end experience the exact opposite, an inertial component accelerating upward. The center of the rocket is constantly pulling both ends to its orbital path and velocity. Only the structure of the rocket is preventing the two ends from flying off in opposite directions. One to a higher orbit, the other to a lower orbit.

In a steep enough gravitational field, these tidal forces can be strong enough to tear the booster in two... Indeed... these are the forces that prevent any large moon from remaining intact within a certain radius of both Saturn and Jupiter. The tidal stress tears them into pieces.

The exact same forces apply to the Earth and moon, High tide occurs when the moon is either directly overhead, or directly on the opposite side of the earth.

The water on BOTH sides of the earth, being unrestrained, rises in direct proportion to the inertial component imparted by their orbit around the Earth/Moon barycenter.

It is the exact same phenomenon as with the booster. And the fact that the Moon does not have uniform mass is why its rotation is tidally locked- with its longest mass axis being radial to its orbit.

Eventually, Earth will also become tidally locked as the moon bleeds our rotational energy into a higher and higher orbit.

The Sun exerts a much less noticeable effect, because, relative to is orbit, the diameter of the earth represents such an small difference in orbital speeds.

So there are two different sets of tidal humps in the oceans... One major, the other minor. But when the moon and the sun are on precisely opposite sides of the earth, or the same side... the solar tide is superimposed on top of the height of the lunar tide.

Sea depth, currents, and other factors determine the actual tides that are experienced in any given location.

Some Other Points

The moon mainly, but the sun also has a small effect on the tides, as well as some very minor influence coming from the major planets of our solar system.

The causes of high tides and low tides are from the position of the Sun, Moon, and the Earth. When the Sun, Moon, and Earth are all aligned they form Spring Tides. Spring Tides are high tides. When the Sun, Moon, and Earth form a 90 degree angle they form Neap Tides. Neap tides are lower tides.

The gravitational attraction of open water to the moon. The moon's position around the earth affects the height of the tides.

Gravitational forces cause the water, and to some extent

the land itself, to move toward the Sun and Moon.

An important factor is the Earth's rotation. This causes the "bulges" of water

to move around the planet as the Earth rotates "beneath" the Moon.

There are usually two high tides per day. The high tide on the side facing the Moon is easy to understand.

The high tide on the side of the Earth facing away from the Moon is harder to understand. However, it can be shown mathematically that the effect of the Moon's gravity is to elongate the Earth in the direction along a line joining Earth and Moon. Hence there are two bulges.
the gravitaional pull of the moon and the son affects--causes the tides
Tide-generating forces (TGF) are a result of the gravitational attraction between the earth, the sun, and the moon and the centrifugal force due to the relative motions of the moon around the earth, and the earth around the sun. While these forces exactly balance on average, the local mismatch at the earth's surface creates a horizontal force directed towards the surface points closest and farthest from the moon (the "lunar" TGF) and the sun (the "solar" TGF).

Tides are caused by the Moon's gravity pulling on the water on the Earth.

the gravitational pull of the moon and the sun affects--causes the tides

Correct Answer:

The above answers are incorrect. Tides are a function of orbital mechanics. They are not, specifically, gravitational, they are inertial.

The moon is in orbit around the earth, but it's orbital equilibrium exists solely at its center of gravity. Because the moon is effectively a solid, all parts of the moon move with its center of gravity. However, the portion of the moon that is farther away than the C of G is moving too fast to be in orbital equilibrium.... And the portion of the moon closer to earth than the moon's C of G is moving too slow to be in orbital equilibrium, given its distance.

If the moon were to be abruptly cut in half thru it's C of G, the further half would move away from earth into a higher orbit that balances with its velocity and mass, and the closer half would fall to a lower orbit that balances with its velocity and mass.

This is, clearly, NOT a centrifugal force, as a system under centrifugal force would result in BOTH Halves moving away... If free to move closer to the Earth, the closer half of the moon would not fall to Earth; rather it would move closer and increase its speed thru conservation of momentum, until it had reached a new, stable orbit at a closer distance.

At no time does the holding force of gravity change on either half... The force is strictly each component part of an orbiting body wanting to move into orbital equilibrium given it's velocity, mass and distance from two or more gravitational sources. Because the earth and moon are in orbit around a common barycenter, the same force, pulling the closer and further halves apart applies to earth.

Because water is not solid, it can actually move as a result of this force... However the force is not as strong as the force of earth's gravity, and so manifests as an offset to the weight of the water. The water on the side closer to the moon rises because it wants to fall into a closer, faster orbit... and at the same time the water on the opposite side of the earth, furthest from the moon, rises, too, because it wants to move into a higher, slower orbit. Objects under tidal force are being pulled in two opposite directions... not by gravity, but by conservation of momentum within a gravitational field.

Under a steep enough gravitational gradient, such as near a neutron star, these tidal forces can exceed the strength of materials and literally tear things apart. Moons that drift too close to a massive primary shatter, and the distance at which they shatter is a function of their size and density.

Further, The slightest asymmetry in mass distribution in an orbiting pair results in tidal forces being greatest when the longest axis of mass is aligned with the barycenter of the system. ( for example, a long thin structure like a rocket, in free orbit, will eventually align itself so that it is pointing longwise, perpendicular to its orbital path, a straight tube pointing at the mass it is orbiting. )

This effect dampens rotational inertial, and ultimately results in "tidal locking". That is, the object only rotates at the speed that keeps its long mass axis aligned with the barycenter.

The Earth's moon is tidally locked, with one face perpetually pointing toward earth. The earth's larger mass, and the fact that the earth/moon barycenter is within earth's volume results in a vastly diminished tidal locking force on the Earth, but, it is still there and, eventually, the Earth will become tidally locked with the moon, and earth's day will be the same length as the moon's.

Edit: This question is famous for generating lots if answers, even among scientists. All I want to say is that I think tides are caused mainly by gravity.

The influence of the Sun's & Moon's gravity on the water in the Oceans.

The answer to your question is related to gravity.Gravity is the force that pulls two objects toward each other, Earth may be bigger than it's moon. But it's moon can pull the Earth and when this happens some of the water is carried away because of the pull that the moon cause.

The cause of ocean tides on earth is the slight gravitational pull of the moon.
the Gravity that's on earth and its atmosphere
Ultimately, gravity. Gravitational attraction falls off with distance, so the moon actually pulls harder on the part of the Earth that's closest to it. When that part is rock, there's not a whole lot of give, but when it's water, it "mounds up" slightly, and that's what the tides are. Some complications: * Because it pulls LESS strongly on the side OPPOSITE, the water there mounds up as well, pointing in the opposite direction. * For various reasons (mainly, it takes a while to move that much water) the tidal bulge actually lags the moon a bit, so the highest point of high tide does NOT occur when the moon is directly overhead.
the tides are caused by the gravity from the sun and moon,the closer they get the higher the tide gets!
Tide-generating forces (TGF) are a result of the gravitational attraction between the earth, the sun, and the moon and the centrifugal force due to the relative motions of the moon around the earth, and the earth around the sun. While these forces exactly balance on average, the local mismatch at the earth's surface creates a horizontal force directed towards the surface points closest and farthest from the moon (the "lunar" TGF) and the sun (the "solar" TGF).

Tides are caused by the Moon's gravity pulling on the water on the Earth.

== ==
the gravitaional pull of the moon and the son affects--causes the tides
The (differential) gravitational pull of the moon and the sun. But it can also be caused by the wind that blows over the ocean.
answ2. The tides are caused by the pull of gravity of the Moon. And to a lesser amount by the gravity pull from the Sun.

When there is a New Moon, the Sun and Moon are in alignment, (on the same side of the earth), and the tides are higher than that at all other times.

When there is a full moon, the Moon and the Sun are opposed, (they are on opposite sides of the earth), and the high tides then will be lower than those of a New Moon.

As to the second tide each day, when the moon is exerting its pull on the earth, the tide will be full on the side near the Moon.

BUT, on the side of the earth farthest from the Moon, the centre of gravity of the Earth - Moon pair will be slightly further away and thus the tides will be able to be higher, as the force of gravity is less.

On the rare occasions when the orbit of Marsbrings it close to the Earth, then when the Earth, Moon and Sun are all in alignment, there will be exceptionally high tides. But not very often does this happen.
The daily tides of the oceans are caused by the gravitational pull of the moon. The height of the tides is governed by addtional factors such as local geography (i.e. shape of terrain, bay configuration, etc.), by the proximity of the moon to earth and the pull of the sun. Spring tides occur when the Sun's pull is added to the moon's and Neap tides when the Sun's attraction partially cancels the moon's.
It has to do with the moon. If the moon is a new moon then the tides will go east but if it is a full moon then they will go west and all in between!

Answer 3

The Moon and the Sun cause the tides. The oceans are pulled outwards by their gravity on the side nearer to them. This causes a 'bulge' on that side of the Earth, and places there experience high tide. On the opposite side of the Earth there is another bulge, because the Sun/Moon pull is weakest there and there is least tendency for the water to move towards the pull. As the Earth rotates any given place will pass through a bulge twice a day, so will experience two high tides. Low tides happen as we pass through positions 90 degrees away from the bulges. The shape of the land interacting with these tidal bulges complicates the exact tide times considerably, and the tidal range also, so you need to consult data for your own locality if you want to know exactly when the tide will come in.http://www.ukho.gov.uk/Easytide/easytide/SelectPort.aspx

http://usharbors.com/tide-charts
The situation is complicated by the fact that the angle between the Sun and the Moon is constantly changing as the Moon moves in its orbit, so their resultant pull varies too. This means that the height of the high tide is largest, and of the low tide is lowest, when the Sun and Moon are in line on the same side of the Earth, which happens at New Moon. You will find some good animations and more details here:

http://scijinks.jpl.NASA.gov/tides/

Answer 4

The movement of tides is caused by the moon's gravitational force.