30% hydrogen peroxide is added to a potassium iodide catalyst, detergent and food colouring, and oxygen bubbles rapidly produce a foam.

A small teaspoon of solid potassium iodide, a squirt of detergent, and a few drops of food colouring are put into a measuring cylinder of any size placed into a tray. 30% Hydrogen Peroxide is added, and coloured foam is formed rapidly, spurting out of the top.

Elephant's Toothpaste in Graduated Cylinder - Amy Kabrhel:

📄 With 3% hydrogen peroxide and yeast catalyst - Science Buddies: https://www.sciencebuddies.org/stem-activities/elephant-toothpaste
📄 With 30% hydrogen peroxide and potassium iodide catalyst - Thought Co: https://www.thoughtco.com/elephant-toothpaste-chemistry-demonstration-604250
🎞️ A very large example in a swimming pool - Mark Rober: https://www.youtube.com/watch?v=Kou7ur5xt_4
🎞️ World's Tallest - Mark Rober: https://www.youtube.com/watch?v=e09xig209cQ

• Using 3 or 6% Hydrogen Peroxide will make the foam form much slower, but it will still overflow the measuring cylinder.
• Using a conical flask instead of measuring cylinder can make the foam shoot higher, and it can reach the roof.
• Putting a glowing splint into the foam afterwards can make it glow brighter, but the foam also helps to extinguish it so it probably can't be made to relight.
• Use different catalysts, including yeast and aqueous potassium iodide.

• Safety glasses required
• Student should stand back at least 1 metre
• Gloves may be worn

• What is the reaction occurring?
• What gas is produced?
• What is the evidence of a gas being produced?
• What is the evidence of a chemical change?
• How does the concentration of the Hydrogen Peroxide affect the reaction rate?