Elephant toothpaste is an exciting science experiment for children to learn about chemical reactions. It gets its name from the fast-moving foam produced, which looks like a giant tube of toothpaste being squeezed.
How does elephant toothpaste work? When you mix yeast into hydrogen peroxide, the hydrogen peroxide breaks down rapidly into a large amount of oxygen and water. This causes the mixture to expand at a speedy rate and explode out of the bottle. The added washing-up liquid turns it into a foam by trapping the oxygen bubbles.
It’s important to note that although this easy elephant toothpaste recipe is a science activity for children, it does require grown-up supervision as it uses hydrogen peroxide. We’ve used a low strength (3%) which isn’t caustic, but can irritate skin and eyes. It’s essential that only adults handle the chemical and make sure children know not to drink or touch it. We would also recommend wearing safety goggles, in case of splashes.
Although the resulting foam is made of oxygen, water and soap, it can be hot and contain traces of un-reacted hydrogen peroxide, so it’s best not to touch it. The foam can be safely washed down the sink after you’re finished.
Elephant toothpaste recipe
Makes 1 bottle of elephant toothpaste
Prep 10 minutes
You will need
- 125ml 3% hydrogen peroxide
- A squirt of washing-up liquid
- A few drops of gel food colouring
- 2 tbsp warm water
- 1 tsp fast-action yeast
1) Put a clean and dry empty 500ml plastic bottle in a non-reactive bowl or oven dish.
2) Put a funnel in the top of bottle and carefully pour in the hydrogen peroxide (this needs to be done by an adult).
3) Remove the funnel straight into a sink or bowl, being careful not to drip any hydrogen peroxide that may still be in it.
4) Add a squirt of washing-up liquid to the bottle.
5) Add a few drops of food colouring to the bottle, then gently shake the bottle to mix all the ingredients together, making sure to keep it upright.
6) Stir the yeast and warm water together in a small jug.
7) When you’re ready to do the experiment, pour the yeast mixture into the bottle and move away quickly. The two mixtures will react together and burst out of the bottle. Wash the foam down the sink after the experiment.
Watch our step-by-step video to see it in action!