Spring, with its changeable weather and frequent showers, is a good time to talk about one of nature's most spectacular and colorful displays - the rainbow.

For a rainbow to form, rain must be falling in one part of the sky while sunshine is breaking through on the opposite side. And you, the observer, must be in between. A rainbow forms as sunlight from behind you enters raindrops in front of you. Some of that sunlight is reflected back towards you. In addition, when light enters and leaves a drop of water it's dispersed, or broken up, into all the colors that make up sunlight, just as would happen in a prism, and that's where the colors of the rainbow come from.

In a very general way, the setup for a rainbow resembles a movie theatre. The sun is the projector, the screen is the rainbow, and you're in the middle watching.