Throughout history, rainbows have been a source of mystery and legend. Rainbows are also important symbols in a number of cultures around the world.

In the Old Testament of the Bible, for example, God shows Noah a rainbow to let him know that the Flood is over and that he will never destroy the earth again with flooding. An ancient Mayan book also tells of a rainbow signaling a new age after the destruction of the earth.

In a myth from Germany, the rainbow is the palette that God used to paint the birds. Some Native American groups believed that rainbows were made from wild flowers. In other traditions, the rainbow is the hem of a particular god's coat.

In an ancient Japanese myth, the rainbow is a bridge from heaven to earth. The first man and woman walked down this bridge to learn the ways of the world.

Today, we know exactly how rainbows are made. In the seventeenth century, the scientist Isaac Newton and the mathematician and philosopher Rene Descartes analyzed them very carefully. They concluded that rainbows were caused when sunlight was broken up as it passed through raindrops.

When it rains, the colors that make up white light separate because they bend at different angles when they pass through water. The result is the full spectrum of colors the human eye can see, as well as some that it cannot; at the outermost edges of a rainbow lie ultraviolet and infrared light.