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At-Home Science Experiments: Elephant's Toothpaste

The foam you'll create in this experiment resembles toothpaste being squeezed from a tube — but don't get it in your mouth!
 

Learning Benefits

Hover over each Learning Benefit below for a detailed explanation.
Observation
Experimentation

What You'll Need:

  • A clean 16-oz plastic soda bottle
  • 1/2 cup 20-volume hydrogen peroxide liquid (20-volume is a 6% solution, ask an adult to get this from a beauty supply store or hair salon)
  • 1 Tablespoon (one packet) of dry yeast
  • 3 Tablespoons of warm water
  • Liquid dishwashing soap
  • Food coloring
  • Small cup
  • Safety goggles 

What To Do:

Note: As you can see from the picture, foam will overflow from the bottle, so be sure to do this experiment on a washable surface, or place the bottle on a tray.

1. Hydrogen peroxide can irritate skin and eyes, so put on those safety goggles and ask an adult to carefully pour the hydrogen peroxide into the bottle.

2. Add 8 drops of your favorite food coloring into the bottle. 

3. Add about 1 tablespoon of liquid dish soap into the bottle and swish the bottle around a bit to mix it. 

4. In a separate small cup, combine the warm water and the yeast together and mix for about 30 seconds.

5. Now the adventure starts! Pour the yeast water mixture into the bottle (a funnel helps here) and watch the foaminess begin! 

What's Happening:

 Foam is awesome! The foam you made is special because each tiny foam bubble is filled with oxygen. The yeast acted as a catalyst (a helper) to remove the oxygen from the hydrogen peroxide. Since it did this very fast, it created lots and lots of bubbles. Did you notice the bottle got warm? Your experiment created a reaction called an exothermic reaction, which means it not only created foam, it created heat! The foam produced is just water, soap, and oxygen, so you can clean it up with a sponge and pour any extra liquid left in the bottle down the drain.

The experiment can also be done with the hair care version of hydrogen peroxide, or the weaker pharmacy version, although the effect with the pharmacy version will be smaller. Readers should use safety goggles for any experiment, and should have parents read instructions on containers for safety precautions.

Activity and images courtesy of ScienceBob.com.

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