• Sarah Caughron

Elephant Toothpaste

Updated: Apr 10, 2020

Elephant Toothpaste Experiment

This cool chemistry experiment is called Elephant Toothpaste because the foamy reaction looks like toothpaste coming out of the bottle, and the size of the foam stream looks large enough for an elephant’s toothbrush. In this classic chemistry experiment, we observe how a catalyst creates an exothermic reaction.


  • A clean, 16-ounce plastic soda bottle

  • ½ cup 20-volume hydrogen peroxide LIQUID (like from a beauty supply store)

  • 1 TBS (one packet) of dry yeast

  • 3 TBS warm water (but not too hot)

  • Liquid dishwashing soap

  • Stirring stick or popsicle stick

  • Food coloring

  • Cup for mixing yeast/water

  • funnel/small cup

  • Safety goggles (if you have them)

  • Tray or pan in which to place plastic bottle (the experiment overflows, so you need space for the mess!)

  • Towels for any clean up.


  • Apply safety goggles

  • Mix yeast and warm water together. Set aside.

  • Put an empty bottle in the middle of the pan or tray.

  • Funnel or pour ½ cup peroxide into the bottle

  • Add a large squirt of dish soap and a few squirts of food coloring to bottle. Swirl to combine.

  • Pour the yeast mixture into the bottle and watch what happens. It may take a few seconds to react, but the result is well worth the wait.

  • When you are finished, it is safe to dispose of all of the demonstration materials either by throwing them away in the trash can or by washing them down the drain.

What’s happening:

The yeast works as a catalyst (speeds up the chemical reaction) to release the oxygen molecules from the hydrogen peroxide solution. Each bubble we observe is filled with oxygen! The oxygen-filled bubbles, which make up the foam, are actually the remainder of what happens when the hydrogen peroxide breaks down into water (H2O) and oxygen (O2). The bottle will feel warm to the touch because this is an exothermic reaction in which energy, in the form of heat, is given off.

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