The elephant toothpaste experiment

What you’ll need:

  • 3% hydrogen peroxide
  • Liquid dish soap
  • Food coloring (optional)
  • Instant dry yeast
  • Warm water
  • Clear container (around 12 oz. to 24 oz. but different sizes are okay)
  • Cookie sheet or a pan to collect foam
  • Safety goggles
  • Funnel depending on the shape of your clear container

This is a fun, visual experiment that illustrates chemical reactions. 

Even though it’s called elephant toothpaste, it is NOT actually toothpaste. The awesome foam we’ll see is a result of the liquid dish soap. You definitely don’t want to put it in your mouth!



Let’s get started!

Safety first—hydrogen peroxide can irritate your eyes.

Put on your safety goggles.

Place your clear container on the cookie sheet or flat pan.

This will make for easier clean-up at the end.

Measure ½ cup of hydrogen peroxide and pour it into your clear container (use the funnel if necessary). Add a generous squirt of liquid dish soap. If you want to measure, 1 tbsp. should be good. Next, add a few drops of food coloring.

Gently swirl the container to get everything mixed together. 

In a separate cup, mix 1 tbsp. of dry yeast with 3 tbsp. of warm water. Mix for about 30 seconds. If the mixture forms more of a paste, add a little more water. You’ll want to be liquid enough to pour into your clear container.

Now the fun part!

If necessary, use your funnel to pour your yeast/water mixture into a clear container. Stand back—you should see foam building up and likely spilling over the top of your clear container. Does it look like a big tube of toothpaste?

What’s going on?

The chemical name for hydrogen peroxide is H2O2. When it breaks down, it forms H2O and O2, or what we commonly know them as, water and oxygen. This breakdown slowly happens overtime but with this experiment, we’re speeding things up a bit with the introduction of a catalyst—the yeast.

Yeast contains an enzyme called “catalase”, which forces the breakdown of the hydrogen peroxide molecule to happen much quicker.

Fun fact: you probably know about hydrogen peroxide as the stuff you pour in a cut or scrape to kill bacteria. The foaming you see when your pour hydrogen peroxide into a cut is the reaction of the hydrogen peroxide and the catalase that naturally occurs in your body. The oxygen produced after the reaction kills the bacteria!

If we just poured the yeast/water mixture into hydrogen peroxide by itself, you would see bubbles as the O2 escaped from the container, but not really any dramatic foaming. 

That’s where the dish soap comes in! By adding the dish soap, the escaping O2 gets trapped in the soap bubbles and—voila--lots and lots of foam!

Clean up:

What you're left with once the foam stops is basically water, soap, and yeast. That means the foam will be safe to wash down the kitchen or bathroom sink. 

You can make this your own by changing up the size and shapes of your container. I had the most success with a 12 oz. glass bottle.

Change the colors of the foam and have fun!