Elephant's toothpaste

Elephant's toothpaste is a foamy substance caused by the quick decomposition of hydrogen peroxide (H2O2) using potassium iodide (KI) or yeast and warm water as a catalyst.

[2][3][4] Because it requires only a small number of ingredients and makes a "volcano of foam", it is a popular experiment for children to perform in school or at parties.

Then, a catalyst, often around 10 ml potassium iodide solution or catalase from baker's yeast, is added to make the hydrogen peroxide decompose very quickly.

Prepare the Mixture: In a container, mix together: ½ cup of hydrogen peroxide (30% solution), A squirt of dish soap, A few drops of food colouring (if desired).

YouTube science entertainer Mark Rober has created a variation of the experiment, named "Devil's Toothpaste", which has a far more pronounced reaction than the version usually performed in classroom settings.