How Does Tides: Crash Course Astronomy #8 Work?

Tides happen because the Moon pulls on Earth’s oceans, just like a big magnet pulls on metal.

Imagine you're holding a bucket of water. If you shake it gently from side to side, the water sloshes around, that's kind of what happens with tides, but instead of your hand, it's the Moon doing the shaking.

The Moon’s gravity is like an invisible hand pulling on Earth’s oceans. When the Moon is close to a part of Earth, that ocean gets pulled toward the Moon, creating a high tide there. At the same time, on the opposite side of Earth, another high tide happens because the water is being "pulled away" from the middle, it's like when you pull both ends of a rope and the middle bunches up.

When the Moon isn’t pulling as strongly, that’s low tide, the ocean goes down, just like when you stop shaking your bucket, and the water settles back to the bottom.

Sometimes the Sun joins in too! When the Sun and Moon line up with Earth, their pulls add up, making really big tides, called spring tides. When they're at right angles, the tides are smaller, those are neap tides.

So tides aren’t magic, they’re just gravity doing a dance with water!