Lesson 8: Rainbow


Activity Developed by the University of Colorado Museum of Natural History

Description/Learning goals:

Prediction – order of the colors





  • Paper towel roll
  • Craft knife or scissors
  • Old CD
  • Pencil
  • Cardboard or cardstock
  • Tape
  • Markers (optional)

Activity Instructions:

  1. If you want to decorate your spectroscope, do that first.
  2. Use a craft knife to cut a slit at a 45 degree angle towards the bottom 4th of the paper towel tube, cutting only about halfway through the tube.
  3. Across from this slit, cut a small square viewing hole.
  4. Trace one end of your paper towel roll on cardboard or cardstock. Cut out and cut a rectangle shaped slit in the center of the circle to let light in.
  5. Tape the circle to the top of your paper towel tube.
  6. Insert the CD into the slit, with the shiny side of the CD facing up.
  7. Take your spectroscope outside, and point up at the sky but NOT directly at the sun. Look through the peephole and you should see a rainbow!
  8. Experiment with other forms of light, like from a candle or a lamp, or when it’s cloudy. How is the rainbow changing?

Science Concepts:

Additional resources

HYPERLINK "https://littlebinsforlittlehands.com/sugar-water-density-rainbow-science-experiment/" https://littlebinsforlittlehands.com/sugar-water-density-rainbow-science-experiment/ connection back to density.

Ways to make rainbows at home

Glass prism

Water spray



To view a rainbow, you have to be between the sun and the rain, so that the light can shine through the water and create the rainbow in a direction you can see it.

Early Learning 101:

Follow Up: