This demonstration shows the effects of heat absorption. Firstly a standard party balloon is inflated, tied and held above a candle flame. The balloon will burst as expected. A second balloon is filled with water and held above the flame very briefly. This time the water inside the balloon absorbs the heat from the flame and the balloon stays intact.
Equipment typically required (per demonstration):
This demonstration may be useful as an end of term filler lesson or as an induction into heat transfer.
- Round party balloon
- Safety screen
The air filled balloon should burst almost immediately when held above the candle flame. This may be conducted behind a safety screen as sometimes hot pieces can be ejected.
Obviously it may be worth holding the water filled balloon over a sink or bucket to catch the water if it bursts. This balloon should only be held in the flame for a couple of seconds as it will burst if held in the flame for a long time, although teachers may want to allow this balloon to burst to show how long each takes to go.
Typical technician preparation time: 5 minutes.