Making A Comet


400mL H2O(l)

400mL CO2(s)

2 spoonfuls sand or dirt

≈1-2mL NH3 (ammonia)

≈1-2mL organic material (corn syrup)


large mixing bowl/large mixing spoon

4 med-sized plastic garbage bags

50cm string

work gloves


paper towels


1. Lay 1 garbage bag flat and line mixing bowl with it.

2. Place water in lined mixing bowl.

3. Add sand or dirt and stir well.

4. Add NH3 

5. Add organic material (stir well).

6. Using gloves, place CO2 in 3 garbage bags that have been placed inside each other.

7. Crush CO2 with hammer.

8. Add CO2 to mixture and stir vigorously until mixture is almost frozen. Just before the mixture is solid, lay about 1/2 of the string into the bowl and form a ball around the string. Lift comet out of bowl using plastic liner and firmly shape/hold it into a "snowball".

9. Unwrap comet when it will hold its shape.