Create Your Own Comet | EcoTarium

Create Your Own Comet

Make sure you work with an adult.

This recipe makes one, 6-inch comet. For a real, life-sized comet, multiply ingredients by 3 trillion!


  • 2 Cups cold liquid H20 (water)
  • 1 Small spoonful frozen H20 (snow works best, but slightly thawed crushed ice will do)
  • 2 Cups frozen C02 (dry ice)*
  • 2 Spoonfuls silicate (sand)
  • 1 Dash solid carbon particles (activated charcoal from pet supply store)
  • 1 Dash NH3 (ammonia)
  • 1 Dash organic material (corn syrup)

You'll also need

  • An adult helper
  • A large mixing bowl (plastic if possible)
  • 4 medium-sized plastic garbage bags or 2 construction strength bags
  • Heavy work gloves (see dry ice warning)
  • A hammer, meat pounder, or rubber mallet
  • A large mixing spoon
  • Popsicle sticks
  • Paper towels


  1. Before making the comet, have an adult crush your dry ice. Place it in a heavy garbage bag and use your hammer or mallet to crush it up. You're done when it looks like snow.
  2. Line your mixing bowl with garbage bags.
  3. Add snow (or crushed ice), water, sand, ammonia, and corn syrup, mixing after each ingredient.
  4. While stirring vigorously, add the dry ice. Continue stirring until almost frozen.
  5. While wearing gloves, lift out your liner and shape contents like you would a snow ball.
  6. Unwrap the comet and use a popsicle stick to explore its contents. Pour on some warm water to form a tail.

*You can find out where to buy dry ice in your neighborhood by checking the yellow pages. When you pick it up, bring a cooler and thick work gloves with you. The boiling temperature of dry ice is about -110 degrees F and if you touch it, it will burn you!

Adapted from