ELI5: Why do tides happen?

Imagine you're holding a balloon filled with water. That balloon is Earth, and the water inside is the ocean.

Now, imagine your friend is holding a magnet, and that magnet is the Moon. The Moon's gravity is like that magnet, pulling on everything on Earth, including the water in the ocean.

• The side of Earth closest to the Moon feels the pull the strongest. This is like your friend pulling on one side of the balloon, making the water bulge out a little. This bulge is a high tide.

• But here's the tricky part: the opposite side of the Earth also has a high tide! Why? Because the Moon is pulling the whole Earth towards it. It's like you're pulling the balloon away from the water on the other side, making that water bulge out too.

In between the high tides, the water has to go somewhere. So, the water gets pulled away from the sides of Earth that are not facing the Moon, creating low tides.

As the Earth spins, different places on Earth pass through these bulges (high tides) and the dips (low tides). That's why we have about two high tides and two low tides every day. The Sun also has a smaller effect on tides, but the Moon's pull is much stronger because it's closer to us. So, basically, tides are the ocean's way of responding to the Moon's gravitational tug!