Have you ever seen a rainbow? Sometimes when the sun is shining and it is rainy somewhere at the same time, you can see a rainbow. It's a huge arch of colours in the sky. It's caused by the light from the sun being broken up by water droplets in the atmosphere. The sun's light is "white", but the water droplets break it up into seven different colours, always in this order: Red, Orange, Yellow, Green, Blue, Indigo and Violet. Try to use all of these colors on your hair!