Why does a rainbow come when the rain goes away?

A rainbow appears when the rain stops because light plays hide-and-seek with water droplets in the air.

When it’s raining, water droplets are floating all around, like tiny balls of glass. When the sun comes out after the rain, its light shines through these droplets.

This light isn’t just one color, it's actually made up of many colors mixed together, like how a prism can split white paint into red, blue, green, and more. The water droplets act like tiny prisms, bending the light in different directions depending on its color.

Each color takes a slightly different path through the droplet, which means each color comes out at a slightly different angle, just like how your shadow moves when you walk around a lamp.

Because all these water droplets are floating up in the sky after the rain stops, they each bend the light differently. When we look up, we see all those colors spread out, forming an arc, that’s a rainbow!

It's like when you spray water from a hose on a sunny day and watch the light dance around the mist, only much bigger!