This experiment uses a computer CD or DVD. If you have ever looked closely at either a music or computer CD, you have probably noticed that they produce rainbows. If you hold the CD with the shiny side up and let light from a lamp reflect off of it, you will see a very nice rainbow of colors. If you are using a regular incandescent bulb, you will see all of the colors of the rainbow: Red, orange, yellow, green, blue, indigo, violet. If you use other kinds of bulbs, you may find some colors missing.