Balloons and fire don’t mix — or do they? This trick used to be a favourite among magicians in the Victorian era. You can try it out and amaze your friends. This is also a great way to learn about water’s heat-conducting properties.
Blow up a balloon. Light a candle. Take the balloon gradually near the flame. The balloon pops immediately even before it can come into contact with the flame. This shows that balloons cannot withstand heat.
Now, take another balloon, fill it with a little water, blow it up with air, and tie it. Repeat the earlier experiment and gradually take the balloon near the flame. You can take it close enough to the flame so that the balloon touches it. Unlike the other balloon, this one won’t pop. After 10 seconds or so, you’ll notice that there’s a deposit of soot on the balloon despite which it doesn’t pop! Can you guess why?
Water is a conductor of heat The thin latex balloon allows the heat to pass through quickly and warms the water. As the water closest to the flame heats up, it rises, and it is replaced by cooler water from the top. The process then repeats itself. In fact, this happens so often that it keeps the balloon from popping for a long time! The soot at the bottom of the balloon is carbon. The carbon was deposited by the flame, as a result of which the balloon remains intact.
(CAUTION - This experiment uses a flame and must be performed under adult supervision only)
You need
A couple of regular latex balloons
A candle and a matchbox
Some tap water
Courtesy: The Science Factory