November, 2015
Kids, in a variation of Dancing Raisins (ChemShorts for Kids, Feb. 1992; http://chicagoacs.org/articles.php?id=30), let's make some colorful Dancing Worms!
You'll need gummy worms, baking soda (sodium bicarbonate), water (H2O), vinegar (dilute acetic acid), 2 glasses, and scissors.
With an adult partner's help, use the scissors to cut the gummy worms in half or into quarters lengthwise. You want long, thin strips of worm. Drop the worm strips in one glass. Add a couple of spoonfuls of baking soda and enough water to dissolve some of the baking soda. If all of the baking soda dissolves, add more until some undissolved powder remains. Let the worms soak in the baking soda solution for 15 minutes to half an hour.
Pour vinegar into the other glass and drop a baking-soda-soaked worm into the vinegar. What happens? At first, nothing much. But after a while bubbles start to form on the surface of the worm. Then the worm starts to move. After some time, the reaction stops and the worm slows down and stops moving entirely.
Why Do the Worms Move? The gummy worms wriggle because a chemical reaction between sodium bicarbonate and acetic acid produces carbon dioxide gas. The tiny gas bubbles released by the reaction stick to the body of the gummy worms, eventually merging into bubbles big enough to float part of the worm. If the gas bubble detaches, it floats to the surface while that part of the gummy worm sinks back down.
Tips for Success
If your worms never dance then have an adult partner cut them thinner. A thinner gummy worm is a lighter gummy worm and thus much easier to make move. Thin worms absorb baking soda better, too. Or you can try adding more baking soda to the soaking solution or soaking the worms longer. The baking soda needs to get into the gelatin that makes up the worms so that it can react with the vinegar to make bubbles.
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References:
http://chemistry.about.com/od/chemistryactivities/fl/Frankenworms-Dancing-Gummy-Worms-Science-Experiment.htm
Editor, Dr. Kathleen Carrado Gregar, Argonne National Laboratory
