Release the Rainbow

In this activity, you will create a water prism to break light into the seven colors of the rainbow.

Required Materials

  • A sunny window
  • A big bowl full of water
  • A small mirror
  • A sheet of white paper

Activity Directions

  1. Set the bowl near the window.
  2. Place the mirror part way into the water facing the light.
  3. Hold the piece of paper up to intercept the reflection.
  4. Splash! Roy G. Biv should appear on the paper in bands of color.

Here's What's Happening

This experiment demonstrates what happens when light is refracted. When light enters another substance of a different density, it slows down or speeds up. This translates into bending. The thing is, white light is made up of many different wavelengths. Each of these wavelengths bends differently. Violet light bends the most and red light bends the least. The difference in angle means the light leaves the water in different positions, showing as bands of color. We don’t usually see this effect of refraction because the split light is too small. In this experiment the mirror amplifies the visible spectrum.