The moon's gravitational force pulls water towards it, creating a high tide on the surface of the ocean closest to the moon. Also, the centrifugal force created by the Earth and moon orbiting around a central point creates a similar bulge on the opposite side, creating a second high tide.
Ordinarily, the Earth's gravitational field pulls down on the liquid on the planet's surface. The moon's own gravity partially offsets this effect, resulting in slightly lower gravity on the side of the Earth facing the moon. This change in the gravitational field is not strong enough to affect most solid objects, but the water molecules in the oceans and other large bodies are susceptible to the change, creating a bulge in the surface of the water that follows the moon around the Earth. Water on the opposite side of the planet is not affected by this gravitational pull, since the Earth's mass is in the way. This water is affected by the centrifugal force of the planetary spin, pushing it outwards.
The sun also has a small effect on the Earth's tides. When the moon and sun line up, the tides created are higher than those that occur when the moon's gravity is working perpendicular to the sun's own pull. In addition, the moon's variable distance from the Earth during its orbit can also have an effect on the height of tidal variations.Learn More
According to Science and the Sea, lunar tides are the most common tides and are caused by the Moon's gravity. Although the Sun's gravity is stronger, it is farther from the Earth than the Moon, which is why lunar tides are more than two times stronger than solar tides.Full Answer >
The basic lunar cycle of a body of water consists of two high tides and two low tides, which occur every 24 hours and 50 minutes. The basic cycle of solar tides is 24 hours.Full Answer >
Tides are caused by a combination of three factors: the moon's gravity, the sun's gravity and the earth's own gravity. The moon's gravity is the most significant of these forces; it exerts 2.2 times more force on the tides than the sun's gravity does.Full Answer >
According to the National Oceanic and Atmospheric Administration, the tides are caused by the gravitational force that pulls on the water and the forces exerted by the moon and the sun. The gravitational pull of the moon cause the ocean to bulge out in its direction, while another bulge occurs on the opposite side of the earth.Full Answer >