How to make a foam monster
"Elephant Toothpaste" at home
Wear protective gloves, eyewear, and a mask. Perform this experiment in a well-ventilated area, and on a plastic tray or disposable tablecloth.
Reagents and equipment
- 100 mL hydrogen peroxide solution (we recommend 30%: the higher the concentration, the more spectacular the result);
- 50 mL saturated potassium permanganate solution;
- liquid soap;
- food coloring (dye);
- 2 glasses;
- glass rod.
Pour some liquid soap and dye into the cylinder and add 100 mL 30% hydrogen peroxide solution. Mix thoroughly. Quickly add 50 mL saturated potassium permanganate solution. Observe the rapid formation of foam!
The interaction between potassium permanganate and hydrogen peroxide produces gaseous oxygen, which makes the soap foam.
2KMnO₄ + 3H₂O₂ → 2KOH + 2MnO₂ + 3O₂ + 2H₂O
Another reaction is occurring in parallel: the manganese dioxide that forms during the above reaction catalyzes hydrogen peroxide’s decomposition to oxygen and water.
2H₂O₂ → 2H₂O + O₂