Foamy toothpaste experiment

Foamy toothpaste experiment

Watch the faces of your little scientists as they do this foamy toothpaste experiment. Their eyes will be wide with amazement as the toothpaste-like foam oozes out like elepghant’s toothpaste! This kids science experiment does require safety precautions to be taken and an adult’s involvement but it’s incredibly fun and educational. Best of all, the clean up afterwards is easy too.

What you need:

  • Safety glasses
  • Smock
  • Clean plastic soda bottle
  • 1/2 cup hydrogen peroxide liquid (you can get this from a chemist)
  • 1 tbsp dissolved yeast mixture
  • 3 tbsp warm water
  • Liquid dishwashing soap
  • Food colouring
  • Funnel

Number of players:


Mix the warm water and the yeast together and mix for about 30 seconds until fully dissolved.

Have an adult pour the hydrogen peroxide into the plastic bottle.

Put the funnel in the bottle opening.

Add 3-4 drops of food colouring to the peroxide in the bottle.

Add the dishwashing soap into the bottle.

Pour the dissolved yeast mixture into the bottle and remove the funnel quickly.

Watch as the foam starts to spill up out of the bottle! Soon the foam will start to stream from the bottle, looking like toothpaste being squeezed from a giant tube.



  • The bottle will feel warm to touch as there is an exothermic reaction taking place here.
  • This means the reaction creates heat. The foam is made up of water, soap and oxygen.
  • To clean up after this experiment simply pour any extra liquid in the bottle down the drain and use a sponge to mop up the spilled foam.

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