This is a cool science experiment to show what a great heat conductor water is. You’ll need some balloons, a candle and some water. Check it out and be amazed!….As you might imagine, the secret lies in yet another amazing property of water – it’s ability to conduct heat. Instead of using a paper bag, this modern day version of the demonstration uses an ordinary balloon, some water and a candle. It’s a combination that’s guaranteed to make people stand back.