Flaming gummy bears!

I just stumbled across an amazing – albeit a little obscure – fact: if you ever drop a gummy bear into potassium chlorate, be prepared for a big bang!

The experiment is simple. Put a small amount of potassium chlorate into a glass test tube, and gently heat it. Now drop in a single gummy bear – and stand behind a protective shield. The gummy bear will burst into a flame-shooting reaction for about a minute.

Don’t believe me? You can see an example of this at:
http://blog.wired.com/wiredscience/2008/01/video-gummy-bea.html
(I really recommend watching this video. It’s amazing how many flames a single gummy bear will produce!)

So I have 2 questions about this flaming gummy phenomenon. (1) Why does it happen? And (2) Why should I care?

First, why does it happen? Potassium chlorate is a powerful oxidizer – a substance that burns when you give it a combustible fuel, since it easily gives up oxygen to fuel the reaction. In this case, the combustible fuel is the sugar in the gummy bear. Sugar is a molecule that stores a lot of energy. When that molecule is oxidized rapidly, all of the energy gets released in one quick step. So the amount of energy released by the potassium chlorate is the same as what you would get by metabolizing the gummy bear in your body – the energy is just released more quickly.

So mix the 2 together, and the potassium chlorate releases oxygen molecules, which oxidize the sugar, producing energy in the form of lots of big flames. It’s that simple!

So why should I care? I think it’s a great example of how to illustrate simple chemical concepts in a really fun manner. The concepts here – the amount of energy stored in sugar, and the process of oxidation. If you were to just describe how sugar is a great holder of energy, and oxidizing agents can burn spontaneously, it sounds kind of boring. But show someone a picture of a gummy bear bursting into flames, and all of a sudden science becomes much more fun!