COLUMBUS, Ohio (WCMH) — The annual COSI Science Festival is coming up from May 3 to 6 and NBC4 Today anchor Monica Day got a preview of a crowd favorite experiment: “Elephant Toothpaste” with Kristy Williams.

You can try this one at home with the instructions below. You can also see it on a much bigger scale at the Big Science Celebration May 6 at COSI.

Visit for more information.

Elephant Toothpaste At-Home Instructions


  • Participants in this activity will explore exothermic reactions in a fun and messy way.


  • Exothermic animals are cold-blooded, and rely on external heat sources.
  • Endothermic animals are warm-blooded, and produce their own heat.
  • Exothermic reactions are an energy source for endothermic animals.


  • 16 oz bottle
  • Deep, rectangular baking pan
  • Hydrogen Peroxide
  • Food Coloring
  • Funnel
  • Dawn Dish Soap
  • Yeast
  • Warm Water
  • Beaker


  1. Place an empty 16-oz. plastic bottle in a deep, rectangular baking pan (to catch the mess). 
  2. Mix 1/2 cup 20-volume hydrogen peroxide (which is found at the drug store) and a few drops of food coloring. 
  3. Use a funnel to add the hydrogen peroxide and a squirt of Dawn dish detergent. 
  4. Add a prepared yeast mixture (1 tsp. of yeast which has been dissolved in 2 tbsp. of very warm water) and immediately remove the funnel. 
  5. Foam will come out of the bottle, followed by the substance which resembles toothpaste being squeezed from the tube. It’s safe to touch the bottle and both substances.

Explaining the experiment

Hydrogen peroxide (H2O2) is made up of two hydrogen atoms and two oxygen atoms. When hydrogen peroxide decomposes, it breaks down to form water (H2O) and oxygen (O2). This reaction is always happening but relatively slowly. The yeast has an enzyme called catalase that makes the chemical reaction happen much more quickly. The soap bubbles that erupt are actually filled with oxygen. As the reaction takes place, you might also see steam rising from the erupting foam. This shows that the reaction is exothermic (gives off heat). This is the kind of reaction warm-blooded animals rely upon in order to create heat inside their bodies and maintain their body temperature.