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
- 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.
- Line your mixing bowl with garbage bags.
- Add snow (or crushed ice), water, sand, ammonia, and corn syrup, mixing after each ingredient.
- While stirring vigorously, add the dry ice. Continue stirring until almost frozen.
- While wearing gloves, lift out your liner and shape contents like you would a snow ball.
- 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 http://whyfiles.org/011comets/index.php?g=6.txt