What is the rise and fall of sea?

The rise and fall of the sea, also known as tides, are caused by the gravitational pull of the moon and the sun on Earth's oceans. The moon exerts the greatest influence, causing the water to bulge out on the side of Earth facing the moon. This creates high tide. On the opposite side of Earth, the water also bulges out slightly, away from the moon, again creating high tide.

The sun also exerts a gravitational pull on Earth's oceans, but its effect is about half that of the moon. The sun's pull creates two additional bulges in the ocean, but they are smaller than the bulges created by the moon. When the sun and the moon are aligned with Earth, their combined gravitational forces create the highest high tides and the lowest low tides. This is known as a spring tide. When the sun and moon are at right angles to Earth, their gravitational forces partially cancel each other out, creating the lowest high tides and highest low tides. This is known as a neap tide.

Tides vary in height from place to place. The shape of the coastline, the depth of the water, and the presence of land masses can all affect the height of the tides. In some places, tides can rise and fall by as much as 10 meters (33 feet), while in other places, they may only rise and fall by a few centimeters (inches).

Tides are important for a variety of reasons. They help to mix the ocean water, which helps to distribute heat around the globe. They also provide a habitat for a variety of marine life.