When do tides occur at the ocean

High tides occur 12 hours and 25 minutes apart, taking six hours and Note: This animation is shown from the perspective of a viewer in the northern hemisphere. From a viewer in the southern hemisphere, the rotation would appear to go clockwise. Welcome What are Tides? Spring tides are tides with the greatest tidal range. They occur exactly halfway between the spring tides, when the Moon is at first or last quarter. The material that follows on tides was cut from Ocean Movements section under Coastal Processes.

Tides are the daily rise and fall of sea level at any given place. The Moon has a greater effect because, although it is much smaller than the Sun, it is much closer. High tide left and low tide right at Bay of Fundy on the Gulf of Maine. The Bay of Fundy has the greatest tidal ranges on Earth at To understand the tides it is easiest to start with the effect of the Moon on Earth.

As the Moon revolves around our planet, its gravity pulls Earth toward it. The lithosphere is unable to move much but the water is pulled by the gravity and a bulge is created. This bulge is the high tide beneath the Moon. This creates a second high tide bulge on the opposite side of Earth from the Moon. Since so much water is pulled into the two high tides, low tides form between the two high tides Figure below. As the Earth rotates beneath the Moon, a single spot will experience two high tides and two low tides every day.

The tidal range is the difference between the ocean level at high tide and the ocean at low tide Figure below. The tidal range in a location depends on a number of factors, including the slope of the seafloor. Water appears to move a greater distance on a gentle slope than on a steep slope. So when the Sun and Moon are aligned, what do you expect the tides to look like?

Waves are additive so when the gravitational pull of both bodies is in the same direction the high tides add and the low tides add Figure below. Highs are higher and lows are lower than at other times through the month. These more extreme tides, with a greater tidal range, are called spring tides. The two tidal bulges caused by inertia and gravity will rotate around the Earth as the moons position changes.

These bulges represent high tides while the flat sides indicate low tides. A lunar day is how long it takes for one point on the Earth to make one complete rotation and end up at the same point in relation to the moon. The reason that a lunar day is longer than a normal hour day is because the moon rotates around the Earth in the same direction that the Earth is spinning.

Tides are very long waves that move across the oceans. They are caused by the gravitational forces exerted on the earth by the moon, and to a lesser extent, the sun. When the highest point in the wave, or the crest, reaches a coast, the coast experiences a high tide.