Video Link:  http://www.youtube.com/watch?v=DjOVW5GImnI

The Sacrificial Gummy Bear

This demonstration vividly and dramatically illustrates the effect that a strong oxidizer has on a fuel.  It should be performed by an instructor to ensure proper safety procedures are followed.  It should be done in a room with very good ventilation and preferably in a fume hood.

MATERIALS

-       A small package of gummy bears

-       Ring-stand and clamp

-       One medium sized pyrex test tube

-       Around 10 g of solid potassium chlorate (KClO₃)

-       Safety shield, goggles, gloves, and a lab coat

-       Meker burner & striker

-       Tongs or long forceps

PRESENTATION

1.       Set up the meker burner so that is about 1 inch from the bottom of the test tube

2.       Make sure that everything is behind the safety shield

3.       Fill the test tube with the KCLO3 provided and ignite the burner

4.       Once the KCLO₃ is melted (this usually takes about 5 minutes) a gummy bear can be dropped in with tongs.  The reaction will begin almost immediately.  (while the KCLO₃ is melting is a good time to explain what’s going to happen or ask the class which color of gummy bear to sacrifice)

5.       The gummy bear will start bouncing around in the test tube violently optimally making a “screaming noise” and emitting purple/orange flames along with a lot of smoke/steam.  This will last about 1 minute.

DISCUSSION

The gummy bear is mostly sugar, which is easily oxidized by something like molten potassium chlorate. Ideally, a balanced equation would show sucrose (C12H22O11) being converted to carbon dioxide and water while the KClO3 becomes KCl. The reaction will not be perfectly balanced in the demonstration as an excess of KCLO₃ works much better.  Also, gummy bears are not pure sucrose.

HAZARDS

Molten KClO3 can cause very severe burns. Think of your skin as another gummy bear. Exercise your best safety technique while presenting this demonstration. There is also a lot of smoke produced during the oxidation as well as a good chance of the test tube breaking. This experiment should only be done in a room with good ventilation or a fume hood.