When you are at the beach during “low tide,” there is a lot less water than there was during “high tide“! Where did all of that water disappear to?? Has it decided to go hang out at a different beach? Will it ever come back??
The answer is “yes,” it will come back, and also “yes,” it kind of has decided to go and hang out at a different beach for a little while!
High and low tides are mostly caused by the pull of gravity coming from the moon, in addition to the gravitational pull shared between the Earth and the moon as they swing around each other in orbit! The sun’s pull of gravity also effects the tides a little bit, but only about half as much as the moon.
What happens is that as certain parts of the Earth turn to face the moon, the special pull of gravity causes the water in the oceans swell in certain directions! The result is that the water on shore in certain parts of the world lowers (low tide) as it’s pulled over to other places where it swells up higher. (High tide.) As our planet and the moon continue to swing around each other, the tides change and places that had low tide get high tide, and vice-verse!