What causes rainbows to appear in the sky, and how are they formed?

Rainbows appear when light from the sun bends and splits into colors after passing through raindrops in the sky.

Imagine you're playing with a prism, that triangular glass thing that makes colors spread out when sunlight goes through it. A rainbow is like a big prism made of millions of tiny raindrops. When sunlight hits a raindrop, some of it bounces off inside the drop and comes back out, but not straight out. It bends, or refracts, just like light bending in a prism.

Now imagine you're on a merry-go-round, spinning around with your friends. As you spin, each friend seems to be in a different place at once, kind of like how the sunlight splits into different colors as it goes through many raindrops. Each color takes a slightly different path, so when we look up, we see them spread out in an arc.

If the sun is behind you and there's rain ahead, you might get to be the center of the rainbow, with colors stretching from one side to the other, like a colorful bridge across the sky!