What are the colors of the Rainbow?

What is a Rainbow? 

Next time you see a rainbow in the sky, look carefully at its colors. On the outside of the rainbow you will see red, and on the inside you will see blue or violet. Sometimes, you can see a faint second rainbow above the first one, with the colors in the opposite order.

A beam of light bends as it passes through a glass prism. The prism splits the light into the colors of the rainbow.

How do rainbows form?

Sunlight appears to have no colors. We call it white light, but it is really made up of different colors. When you see a rainbow, you see white light that has traveled through millions of falling raindrops.

White light is a mixture of all the colors of the rainbow—red, orange, yellow, green, blue, and violet. 

When white light meets a drop of rain, it changes direction. This change of direction is called refraction. Some of the colors in the light change direction more than others, and so the white light separates into its different colors.

Make a rainbow!

You can make your own rainbow using a specially shaped piece of solid glass called a prism. There's a prism in the photograph on the opposite page. White light shines onto one side of the prism and bends as it travels through the glass. When it comes out at the other side, the light has been refracted and separated into its different colors.
On a sunny day, you can also make a rainbow using a mirror.