Why do things have colour?

Grass is green, the sky is blue, a banana is yellow. But where does colour actually come from? The amazing answer is hiding inside light.

Light is full of colours

Sunlight looks plain and white, but it is secretly a mix of every colour all jumbled together — red, orange, yellow, green, blue and more. When you see a rainbow, the raindrops have split the white light apart so you can see all the colours hiding inside it.

Soak up and bounce back

Now here is the trick. When light lands on something, the object soaks up some of the colours and keeps them. The other colours it cannot keep, so it bounces them back out.

The colour that bounces off is the one that flies into your eyes — and that is the colour you see!

A green leaf, a red apple

A leaf soaks up most colours but bounces back the green light, so it looks green. A red apple drinks in the other colours and bounces only red. A white snowman bounces back nearly all the colours at once, which is why it looks bright white.

Wonder fact: Something that looks black is soaking up almost all the colours and bouncing back hardly any. That is why black clothes feel so warm in the sun — they keep the light’s heat!