The elephant toothpaste demo foams up like an elephant squashed a giant tube of toothpaste. Mixing yeast and peroxide with detergent produces foam similar to shaving cream. It can be used to make a chemical volcano or how much yeast is in a packet a kid-friendly elephant toothpaste demo. She has taught science courses at the high school, college, and graduate levels.
4 cup dishwashing soap, and a few drops of food coloring into the bottle. Swish the bottle around to mix the ingredients. Set the bottle in a sink or outdoors or some other place where you won’t mind getting wet foam everywhere. In a separate container, mix a packet of active yeast with a little warm water.
Give the yeast about five minutes to activate before proceeding to the next step. When you are ready to do the demo, pour the yeast mixture into the bottle. The reaction occurs immediately upon the addition of the yeast. In this demonstration, yeast catalyzes the decomposition so it proceeds much more rapidly than normal. The dishwashing detergent captures the oxygen that is released, making foam. In addition to being a nice example of a decomposition reaction and a catalyzed reaction, the elephant toothpaste demo is exothermic, so heat is produced.
However, the reaction just makes the solution warmer, not hot enough to cause burns. You can easily use the elephant toothpaste reaction as a holiday chemistry demonstration. Just add green food coloring to the peroxide and detergent mixture and pour the two solutions into a Christmas tree-shaped container. A good choice is an Erlenmeyer flask because it has a cone shape. The original elephant toothpaste reaction, which uses a much higher concentration of hydrogen peroxide, can cause both chemical burns and thermal burns.
While it produces a larger amount of foam, it’s not safe for kids and should be performed only by an adult using proper safety gear. The kid’s version uses chemicals that are safe for children to touch. The lower concentration of peroxide can still discolor fabrics. Care should be taken to avoid ingestion because the project includes detergent, which can cause vomiting. The original demonstration results from decomposition of hydrogen peroxide catalyzed by potassium iodide.
Detergent solution captures gases to form the foam. The kid-friendly version uses a lower concentration of hydrogen peroxide, with the decomposition catalyzed by yeast. While both versions of the reaction may be performed for a young audience, the original version uses concentrated hydrogen peroxide, which is a strong oxidizer, and potassium iodide, which may not be readily available. The kid-friendly version uses chemicals that are safe for children to touch, in case of a splash. As with all chemistry demonstrations, adult supervision is recommended. Chemical Demonstrations: A Handbook for Teachers of Chemistry.
University of Wisconsin Press, 1983, Madison, Wis. Toxic Substances Portal – Hydrogen Peroxide. Why Does Hydrogen Peroxide Bubble on a Cut? The Ultimate Guide to Baking Bread With Yeast How Much Do You Know About the Essential Ingredient? Yeast used in baking is predominately Saccharomyces cerevisiae.