Trustworthiness - Elephant's Toothpaste

  • This experiment is called Elephant's Toothpaste.  Okay, technically it's a demonstration, but it is still pretty cool to watch.  It is a fairly simple demonstration, but it does require several ingredients.  Please practice safety and wear goggles and protection for your clothes.  Also, only do this activity with adult supervision.

    *An empty, clean, 16 ounce plastic soda bottle (I found Coke worked best)
    *1/2 cup 20-volume hydrogen peroxide liquid (20-volume is a 6% solution.  I found mine at Sally Beauty Supply)
    *1 Tablespoon (one packet) dry yeast
    *3 Tablespoons of warm water
    *Liquid dish washing soap
    *Small cup
    *Safety goggles and a smock of some sort
    *Pie plate (to catch the mess and keep it from running all over the place)
    *Food coloring, if you want your foam to be colored.  It works just fine without color, it will be white.


    1. Pour the peroxide into the plastic bottle.
    2. Add about a tablespoon of dish washing liquid to the bottle.
    3. If you are using food color, add about 5-8 drops into the bottle.
    4. Swish the ingredients around to mix well. (I actually mixed these three ingredients in my large measuring cup and stirred with a plastic spoon.  The spout on the measuring cup made it easy to pour into the bottle.)
    5. In a separate small cup, mix the yeast and water, stirring until mixed well.  If it is too thick it will not work as well, just dilute a bit with water.
    6. Make sure your bottle is sitting in the pie plate, or some other surface that easily cleaned.
    7. Pour the yeast into the bottle and watch the reaction!


    Things to notice:
    Feel of the bottle before adding the yeast and then feel it after the reaction has subsided.  Can you feel a difference?  You should be able to feel the heat from the exothermic reaction.  At this point it is safe to touch the bubbles.  As a matter of fact, you can play with them now.  Just be careful and don't get any in your eyes or mouth.  Also, if you used food color, be careful not to get any on your clothes or anything else you don't want to get stained.