What are ocean tides and why do they happen?
Riding Water Hills
What are ocean tides and why do they happen?
Twice a day, the ocean does something strange. It climbs up the beach like it's decided to visit the sand, then hours later it slides back down and leaves the beach bare. High tide, low tide, high tide, low tide — the rhythm never stops. What invisible hand is tugging all that water around?
The answer is floating above us: the Moon. The Moon's gravity pulls on everything on Earth — rocks, trees, you, me — but most things are too heavy or too stuck-down to budge. Ocean water, though? Ocean water can move. And the Moon pulls it into a bulge on the side of Earth facing the Moon.
