Everyday mySci

What Makes a Rainbow?


Using a CD, a flashlight and a piece of white paper create your own rainbow reflec-tion. Start in a dark room and place the CD on the floor blank side of the CD up. Place the white paper on the wall and secure with a bit of tape. Aim the flashlight at the CD so that the light reflects onto the blank paper. For an added bit of fun have someone hold the flashlight and use crayons to color the design made on the paper. Now you have your own rainbow reflection picture.

Questions to Ask:

  • What colors do you see? (red, orange, yellow, green, blue, purple.)
  • What colors are absent? (brown, black, white, pink, gray.)
  • What patterns can you make by moving the flashlight around?
  • What happens if you hold the flashlight still and move the CD? Try tilting it left to right. Move it farther away from the wall or closer to the wall.
  • How are the colors getting to the paper? (The light is reflecting off the CD.)
  • What else in your house will make a rainbow reflection?