Make a Rainbow

7-10 year olds | half hour

Learn about how light travels and bends when in air and water with this experiment.

What You'll Need

  • black construction paper
  • scissors
  • a torch
  • tape
  • a mirror
  • clear plastic container
  • white card


1. Cut out a circle from your black paper, a bit larger than the area where the light shines out of the torch.
2. Cut a small slit in this paper cut out.
3. Tape the black paper over the torch, so only a little light shines through the slit.
4. Fill the plastic container halfway with water.
5. Place the mirror in the water, leaning it against one side so that it is angled lengthwise in the container.
6. Turn on the covered torch and, holding it up, shine it through the water onto the mirror.
7. With your other hand, hold up the white card so you can see the light reflected from the mirror on it.
8. There will be a rainbow on the white paper! This is because light travelling through water slows down and bends. Each colour of the rainbow travels this way at a different speed and hits the mirror at different times, bending in different ways. Through the mirror and the white card, you can see these colours separated in a rainbow.

Tags: science

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