VIBGYOR — the colours of the rainbow

A rainbow has seven colours, always in the same order: Violet, Indigo, Blue, Green, Yellow, Orange, Red. The first letters make the word VIBGYOR. Many people remember it from the inside of the rainbow outwards; from the outside in, it is ROYGBIV.

A rainbow appears when the sun is behind you and rain is in front of you. Each raindrop acts like a tiny glass prism. Sunlight enters the drop, bends, bounces off the back, and bends again on the way out.

Each colour bends a slightly different amount. Red bends the least and violet bends the most, so the colours separate and spread out into a band.

You never see the same rainbow as the person next to you — the light reaching your eyes comes from different raindrops.