Fire-Resistant Water Balloon

Balloon and flames don't mix, unless you add a little water to conduct heat.

Common sense tells you that it's impossible to boil water in a paper bag, but this classic parlor trick was a favorite of Victorian magicians. The real difficulty in performing this effect is making it look harder than it is! As you might imagine, the secret lies in yet another amazing property of water – its 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.


  • Balloons
  • Water
  • Matches or lighter
  • Candle
  • Safety glasses


  1. Blow up a balloon just as you normally would and tie it off.
  2. Light a candle and place it in the middle of the table.
  3. Put on your safety glasses because it's time to pop the balloon. Hold the balloon a foot or two over the top of the flame and slowly move the balloon closer and closer to the flame until it pops. You'll notice that the flame doesn't have to even touch the balloon before the heat melts the latex and it pops. Let's just say you had to prove what you already know.

Let's repeat the experiment but this time the bottom of the balloon will have a layer of water inside.

  1. Fill the balloon to the top with water – it probably holds a few ounces (60 mL for the scientists) – and then blow it up with air. If you accidentally let go of the balloon before you tie it off, you'll spray yourself and your friends will love it. Just tie off the balloon and get ready for the next step.
  2. Slowly lower the water-filled balloon over the candle and watch as people start to run. Everyone knows that it's going to pop… but for some strange reason it doesn't. If you're very brave, you can actually allow the flame to touch the bottom of the balloon and it still doesn't pop.
  3. Remove the balloon from the heat and carefully examine the soot on the bottom. Yes… there's soot and the balloon didn't pop. Before reading the explanation, try to figure out why the layer of water kept the balloon from popping.

Take It Further!

Now that you know water will prevent a balloon from popping, try other liquids. Try performing the experiment with juices, sodas, and more. Who knows what will happen? One thing is for sure, you'll find out what liquids are the best conductors of heat!

How Does It Work?

Water is a great substance for soaking up heat.  The thin balloon allows the heat to pass through very quickly and warm the water.  As the water closest to the flame heats up, it begins to rise and cooler water replaces it at the bottom of the balloon. This cooler water then soaks up more heat and the process repeats itself. In fact, the exchange of water happens so often that it keeps the balloon from ever popping! The soot on the bottom of the balloon is actually carbon.  The carbon was deposited on the balloon by the flame, and the balloon remains undamaged.

Using water to control heat is a valuable process.  In fact, firefighters in Colorado often use a polymer foam to control large wildfires.  Since polymers soak up a tremendous amount of water, they are useful in controlling and stopping the heat energy in the fire.  Your body even uses water to control heat.  When you exercise, what’s that dripping from your armpits?  EWWW… it’s sweat!  But your body actually uses the water in your sweat to control your internal temperature so you don’t get overheated.