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Hands-On
Science

chemistry and physics

Three Colors of Light

See what happens when you mix together the three primary colors of light: red, green and blue.

Materials

  • Black garbage bag
  • Three plastic cups
  • Three plastic pipettes
  • Red glow stick
  • Green glow stick
  • Blue glow stick
  • Scissors
  • Plastic apron and / or gloves (optional)

Directions

Before beginning the activity, let students know that the glow-stick solution they are working with is safe, but they should still keep it away from their eyes, clothes and hands. This activity works best in a darkened room.

  1. Cover your work area with a black garbage bag.
  2. Cut open the end of each glow stick and pour each colored solution into its own cup.
  3. Use a pipette to take small amounts of each color and create new color combinations on the garbage bag. Because there is only a small amount of glow-stick solution, use one drop at a time to mix colors.
  4. What happens when you mix red and blue, or red and green, or green and blue? What happens when you mix all three colors together?

What's happening?

If you look inside a computer or TV screen, you'll see they contain only three colors of light: red, green and blue. The three specific cone cells in our eyes work together, allowing us to translate these three colors of light into millions of different colors.

When red and blue light are combined, the result is magenta. When green and blue light are combined, they make cyan. Red and green light make yellow. And when all three primary colors of light are combined, we see white light.