Tides, the periodic rise and fall in the levels of large bodies of water, are the product of gravitational forces. They result from the interaction of the Earth with both the sun and the moon, though the moon is the most significant influence year round.Continue Reading
The first person to link tides with the forces of gravity and attraction to planetary bodies was Isaac Newton in 1687. He then surmised that the phenomenon could be at least partially explained through his theory of universal gravitation: that the gravitational attraction between two bodies is directly proportional to their masses, and inversely proportional to the square of the distance between them. The ocean's attraction to the moon causes it to bulge out in the direction of the moon itself. Simultaneously, another bulge occurs on the opposite side of the earth, with the side being pulled toward the moon and away from the water on the far side.
Due to the nature of Earth's rotation, oceans experience two tides each day. Several times a year, oceans worldwide experience particularly strong tides called spring tides. Despite the name, these tides have nothing to do with springtime, but instead pertain to the appearance of new and full moons. During spring tides, the moon, sun and Earth become aligned, thus amplifying the effect of gravitational attraction.Learn more about Tides
High tides are part of a cycle of rising or receding water that lasts for approximately 6 hours and 13 minutes. Low tides last for the same amount of time.Full Answer >
The bottom layer of the ocean is the coldest because cold water has a higher density than warm water. The colder water sinks to the bottom of the ocean. This movement of water creates the ocean currents.Full Answer >
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.Full Answer >
The gravitational pull of the moon controls the rise and fall of tides on Earth and slows the planet's rotation, while the phases of the moon serve as calendar markers for human beings. High tides occur on the portion of the Earth closest to the moon and the portion farthest away. Low tides occur between those two points.Full Answer >