Volcano Eruption

(No - not Vinegar and Bi-Carb!)

Here is a great way for you to make a enormous erruption, better than the old vinegar and bi-carb. Send an email to The Science Boffins and tell us what you think of it. Great to use at Science Parties.

This experiment is one that you can perform safely at home, but you still need that big adult besides you to make sure that nothing goes wrong.

WARNING: Hydrogen Peroxide is corrosive. Although the strengths that are available in the High Street should not be dangerous you still need to observe caution. Wear gloves, goggles and protective clothing when handling the Hydrogen Peroxide. Any splashes in your eyes should be washed out with copious amounts of cold water and splashes on the skin should be washed with lots of cold water. Seek medical advice. Clean away any spillages. Do not leave chemicals in sight or reach of young children.

OK so much for the warnings, now for the fun...


  • Small (500ml / 16 oz.) empty plastic soda bottle (preferably with a narrow neck such as those made by Coca-Cola)
  • 1/2 cup 20-volume hydrogen peroxide (20-volume is 6% solution, purchased from Boots or other chemist
  • A good Squirt of dish detergent like Fairy Liquid
  • About 10 drops of food colouring
  • 1 heaped teaspoon yeast dissolved in 4 tablespoons very warm water
  • Funnel
  • Foil cake pan with 2-inch sides (not really necessary if you can leave a mess of foam behind, like in a garden)
  • Lab goggles, gloves and protective clothing

Hydrogen peroxide is H²O², that is like water (H²O) but with an extra oxygen atom in each molecule. H is the chemical symbol for Hydrogen and O is the symbol for Oxygen. H² means 2 atoms of Hydrogen and yes, you guessed it O² means 2 atoms of Oxygen. O just by itself means 1 atom of Oxygen. So water is made up of 2 Hydrogen atoms and 1 Oxygen atom and when atoms join together, they are called a molecule.

The yeast is used as a catalyst to bubble the extra oxygen out of the solution. The fairy liquid is to encapsulate the oxygen so that it can be seen and the food colour is to make it more visual. Sources indicate that Hydrogen Peroxide can deteriorate with prolonged storage. It is best to use a bottle with a narrow neck because it constricts the cross-section of the flow and therefore increases the flow rate. a funnel is necessary if you don’t have a steady hand.


  1. Pour about half a bottle of peroxide into the empty bottle. You don’t have to be exact.
  2. Squirt in Dish Detergent
  3. Add food colour
  4. Give it all a good swirl/mix around
  5. Add yeast. Excess yeast is no harm. The yeast can be made up before hand. The hot water is to activate the yeast. There is no data how long the yeast will continue to be suitable but it has been used 2 days after activation in hot water with no downside.

The foam is neutral and harmless but it may discolour clothes. Food dye should wash out.

Please learn the word "Catalyst". One mnemonic that could be used is to make a list of the names of cats. The best cats names go on the "A" list otherwise known as the CAT-A-LIST etc. Or choose any other way you like.


A catalyst is a substance that initiates or accelerates a chemical reaction without itself being affected.

By way of example: Have you got a brother or sister?  Suppose that you are having an argument and your brother or sister gets annoyed and throws something at you.  You are quick enough to duck and the object smashes the window.  Mum asks “Did you do that” and you can safely say “No” without lying.  But you were a Catalyst – you made it happen although you did not throw it” Something like that seems to make a good explanation.

Repeat, the result foam is not hazardous except for the staining.  If you feel it is vulnerable, wash down the foam.

Depending on your mix you may produce copious amounts of foam. It may be that a deep pan is not enough to contain the foam. If this is the case, restrict your Volcano Eruption experiment to outside.


Please get in touch, we'll look forward to hearing from you!