How do rainbows form and why do they appear as an arch?

Rainbows happen when sunlight plays hide-and-seek with water droplets in the air, creating a colorful arch that you can see after it rains.

Imagine sunlight as a group of kids running into a puddle. Each kid wears a different colored shirt, red, orange, yellow, green, blue, indigo, and violet. When they run into the water droplet, they slow down and change direction, just like when you walk into a pool and your legs feel funny. This is called refraction.

But it doesn’t stop there. The light bounces around inside the droplet before it leaves, kind of like playing tag in a big round room. When it finally comes out, each color has taken a slightly different path, so we see them spread apart.

Now imagine you're standing on a hill watching the rain fall. Each water droplet acts like a tiny mirror that reflects its own version of the rainbow, but only you can see all those reflections together as one arch because your eyes collect all those little lights from different drops in the sky.

It's like when you throw confetti into the air, each piece flies off on its own path, but from where you're standing, it looks like a beautiful fan shape.