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Elephant Toothpaste

Learn about chemical reactions as you try this experiment! What do the materials look like before, during and after this experiment?

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  • How can you keep track of changes before, during and after this experiment?
  • What do you think is going to happen? (Guessing what is going to happen during an experiment is called a ‘prediction’ or ‘hypothesis’)
  • Will you do this experiment in pairs or small teams?
  • What supplies will you need for this experiment?


  • Safety first! Start by putting on your safety glasses.
  • Place your plastic bottle in the tray or tub for easy clean up.
  • Measure ½ cup of hydrogen peroxide and pour it into the bottle.
  • Add a big squirt of dish soap to the bottle and swirl it gently to mix
  • If you want to add food colouring, add a few drops of food colouring to the bottle.
  • In a measuring cup, mix together one tablespoon of yeast and three tablespoons of warm (not hot!) water. Stir for about 30 seconds.
  • Pour the yeast mixture into the bottle then quickly step back and watch your reaction go!


  • What happened when you added the yeast mixture to the hydrogen peroxide?
  • Was your prediction correct? What happened?
  • When hydrogen peroxide comes into contact with yeast, it starts breaking down into water and oxygen. Oxygen is a gas and wants to escape the liquid. The dish soap traps these bubbles and makes a foam.


  • Empty plastic bottle per pair or team
  • A stir stick that will fit through the opening of the bottle
  • Dry yeast
  • Warm water
  • Liquid dish soap
  • 3% hydrogen peroxide
  • Measuring cups
  • Measuring spoons
  • Safety glasses
  • Large tub or tray to catch the foam
  • Garbage bags to go under the tray in case of overflow
  • Liquid food colouring (optional)
  • Different-shaped bottles or glasses (optional)

Keep it Simple

  • Do this experiment as a big group or in Lodges/Lairs. Work together to measure out the ingredients carefully with the help of a Scouter.

Take it Further

  • Try changing some elements of this experiment to see what changes. What happens if you do not add the dish soap? What happens if you put the ingredients into a differently-shaped bottle