When is high tide occurs

When the highest point in the wave, or the crest, reaches a coast, the coast experiences a high tide. When the lowest point, or the trough, reaches a coast, the coast experiences a low tide.

Imagine the ocean is shaped like a football pointing at the moon. The point facing the moon is formed because the gravitational pull of the moon is strongest on whichever side of the Earth faces it. Gravity pulls the ocean towards the moon and high tide occurs. The bulge on the far side of the Earth is caused by inertia. The water moving away from the moon resists the gravitational forces that attempt to pull it in the opposite direction.

Here, we see the relationship between the tidal cycle and the lunar day. 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. 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. Spring tides occur when the tidal bulges from the Moon and Sun are aligned. The Moon is full in this image; in the bottom image the Moon would appear as a new Moon.

Neap tides are tides that have the smallest tidal range, and they occur when the Earth, the Moon, and the Sun form a 90 o angle Figure below. How do the tides add up to create neap tides? At neap tides, the tidal range relatively small. Neap tides occur when the Earth, the Sun, and the Moon form a right angle; the Moon is in its first or third quarter.

High tides occur about twice a day, about every 12 hours and 25 minutes. The reason is that the Moon takes 24 hours and 50 minutes to rotate once around the Earth so the Moon is over the same location 24 hours and 50 minutes later. Since high tides occur twice a day, one arrives each 12 hours and 25 minutes. What is the time between a high tide and the next low tide?