Elephant's Toothpaste Experiment

Watch a fun foaming reaction in this cool experiment!

Topics: Chemical Reactions

Difficulty: Easy to perform and see results


  • An empty bottle narrow neck

  • Dry Yeast

  • Warm Water

  • Liquid Dish soap

  • Hydrogen Peroxide

  • Food Coloring

  • Large Tub or tray to hold the reaction in


1. Pour ½ cup of hydrogen peroxide into the bottle.

2. Add 1 tablespoon of dish soap and mix it by swirling gently.

3. Add different colors of food coloring to the sides of the bottle. Do not mix the food coloring into the dish soap and hydrogen peroxide mixture.

4. Carefully place this bottle into your large tub or tray. This will be used to prevent the reaction from making a big mess.

5. Mix one tablespoon of yeast and three tablespoons of warm water and stir for 30 seconds

6. Pour the yeast mixture into the bottle and quickly step back and watch the reaction.

7. Watch as the fun foaming reaction occurs!

How It Works:

A decomposition reaction is when a compound separates into the elements or compounds it is made of. For instance, in a decomposition reaction of water, which has a chemical formula of H2O, the water would decompose into H2 (hydrogen) and O2 (oxygen). This is the reaction equation:

Hydrogen Peroxide is not very stable. This allows hydrogen peroxide to decompose into H2O (water) and O2 (oxygen) with light over time (In order to prevent this reaction, hydrogen peroxide is often stored in dark containers). This decomposition reaction can be seen in the following reaction equation:

Although this process does happen in real life, it takes a really long time for the reaction to occur. This means that Hydrogen peroxide can be stored safely for many years without worrying about this reaction or its decomposition.

However, when we add yeast to the hydrogen peroxide, it acts as a catalyst for the decomposition reaction. A catalyst is a material that can be used to speed up the reaction.

Therefore, when we add the yeast to the hydrogen peroxide and dish soap mixture, the Hydrogen peroxide almost immediately starts splitting up into Water and Oxygen. Since oxygen is a gas, it tries to rise up out of the bottle. This agitates the dish soap and causes it to foam up.

As a result, we are able to see the colorful foaming reaction that occurs.

Why is this reaction called Elephant's Toothpaste?

When the foam comes out of the bottle with the stripes of food coloring on it, it almost looks like toothpaste. Since the amount of foam that is produced is so large, it seems to be toothpaste fit for an elephant. That is why this reaction is called the Elephant's toothpaste reaction!

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