Saturday, 15 March 2014

Elephant Toothpaste

Elephant Toothpaste

The Elephant toothpaste science experiment is a great demonstration to perform, so we're going to show you two ways to can perform it yourself. A child friendly version and a much more exciting reaction.

WARNING! If you attempt to make this yourself then take all necessary precautions and wear any necessary safety equipment. Safety advice.

Materials Needed:

  • Hydrogen Peroxide
  • Potassium Iodide
  • Yeast (only for child version)
  • Washing Up Liquid
  • Container (just used to hold contents of reaction)
  • Funnel


Both versions will require adult supervision, this includes the friendlier version for children. As this reaction produces a lot of foam consider where you are going to be doing it. For the child friendly version you could sit your container that's going to produce the Elephant toothpaste in a tray so you can catch all the foam.

For the more exciting version I would probably go outside and remember to wash away the foamy suds with water when you are done. Also having the Elephant toothpaste come out of containers with different size openings will have different reactions as seen in our video. If your bottle opening is very narrow it might be easier to use a funnel when adding the chemicals to it.

Adding Hydrogen Peroxide.

Adding detergent.

Adding yeast.

Foaming yeast.

Experiment (Child friendly version)

  1. Measure out a small amount of your Hydrogen Peroxide into your container.
  2. Add a few drops of the washing up liquid and mix.
  3. Quickly add your yeast to the mix.

Experiment (Exciting version)

  1. Measure out a fair amount of your Hydrogen Peroxide into your container.
  2. Add a few drops of the washing up liquid and mix.
  3. Quickly add your Potassium Iodide to the mix and retreat to a safe distance.
Adding Potassium Iodide.

Elephant's Toothpaste.

Exploding volcano of foam.

Foam mountain.

Variations of the Experiment

  • You can add a fluorescent dye to the mix instead of food colouring before adding your catalyst (the yeast or the Iodide) to produce Elephant toothpaste that will glow under a black light.
  • You can add glow sticks for a similar effect as above, if your container is small and the foam bubbles aren't too thick to stop the light getting through. Although if you open the glow sticks and pour the contents in, it will not be safe to be near children and the glowing effect may be short-lived.
  • You can put a glowing splint into the bubbles and it will re-ignite confirming the presence of oxygen.
Glowing foam.

How Does It Work?

The Elephant toothpaste demonstration is a way of visualising the release of the Oxygen from the decomposition of Hydrogen Peroxide. With our child friendly version that uses yeast as a catalyst the overall equation looks something like this:

H2O2(aq) → H2O(l) + O2(g)

However when you use Iodide as a catalyst to the decomposition of Hydrogen Peroxide something strange happens. It happens in two stages and doesn't consume the Iodide, here is the equation:

H2O2(aq) + I-(s) → OI-(aq) + H2O(l)

H2O2(aq) + OI-(aq) → I-(aq) + H2O(l) + O2(g)

As you can see the Iodide acts as a liberator of the Oxygen holding it briefly just to let it go into the wild. It should be noted that in both cases with the yeast and the Iodide the result is an exothermic reaction, although the Iodide reaction produces more heat. So consider this when choosing a container to hold your Elephant toothpaste reaction in.

The reason this demonstration is called Elephant toothpaste or Elephant's toothpaste is because the foam produced from the oxygen being caught in the detergent looks like toothpaste being squeezed from the tube.

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