In this fun, messy, and easy experiment, create a chemical reaction that produces a toothpaste-like foam that is big enough for elephants!

You Will Need:

  • 1 clean and empty 16-ounce plastic soda bottle
  • ½ cup of 20-volume hydrogen peroxide liquid (20-volume is a 6% solution, so you will need to ask an adult to get this from a beauty store or hair salon)
  • 1 tablespoon/1 packet of dry yeast
  • 3 tablespoons of warm water
  • 1 tablespoon of washing up liquid
  • 8 drops of food colouring
  • 1 small cup
  • 2x safety goggles
  • 2x rubber gloves

This can get quite messy with large amounts of foam rapidly overflowing from the bottle, so conduct this experiment on a washable surface, outside, or place the bottle on a tray.

Before starting the experiment, ensure everyone conducting it is wearing their safety goggles and gloves.

The Experiment

  1. Hydrogen peroxide can harm skin and eyes so put on your safety goggles and rubber gloves and ask an adult to pour the hydrogen peroxide into the bottle.
  2. Add the food colouring to the bottle.
  3. Add the washing up liquid to the bottle and swish the bottle around to mix everything together.
  4. In the small cup, combine the warm water and yeast and mix for 30 seconds.
  5. Pour the yeast mixture into the bottle and embrace yourself for foam!

The Science

Yeast is a catalyst that speeds up the decomposition and breaking down of hydrogen peroxide molecules, causing it to release oxygen gas molecules and water. These oxygen gas molecules get trapped by the washing up liquid and rapidly grow to create fluffy foam, which is comprised of water, soap, and oxygen (not actually toothpaste). The foam looks for an escape route and erupts out of the top of the bottle.

You will also notice that the bottle gets warmer. This is because the reaction produced is an exothermic reaction, which means that heat is released.

Want More Epic Experiments?

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