Non-Popping Balloon

DESCRIPTION:
When water is placed in a balloon, the balloon can be placed over a flame without popping. Water absorbs the heat from the flame, so the rubber of the balloon does not become weak and break like it does with the dry balloon.

TOPICS COVERED:
heat capacity
thermal convection

MATERIALS NEEDED:
– 2 balloons
– lighter/matches
– water

PROCEDURE:
1. Put ~1/4 cup of water in one of the balloons
2. Blow up both balloons and tie off
3. Hold the dry balloon close to a flame until it pops
4. Hold the wet balloon close to a flame, and even touching a flame

ADDITIONAL COMMENTS:
The flame should be under the water in the wet balloon.

SAFETY:
Caution should be taken with open flames to prevent burns, and safety goggles should be worn at all times.

REFERENCES:
Shakhashiri, B.Z. Chemical Demonstrations;  University of Wisconsin Press: Madison, 1983; Vol. 1, pp 14.

STORY:
We usually hold the balloons over people’s heads to pop them (taking caution to not burn anyone!). After the first balloon pops the audience assumes the next one will pop and the person will get wet.

Handout