Dental Care

Elephant Toothpaste

Making Elephant Toothpaste:  A Fun and Educational Science Project

Many people have never heard of elephant toothpaste. 

This foamy substance isn't really toothpaste - people just call it that because when it's made, it looks like enough toothpaste to clean an elephant's teeth.

Making this foam is a fun way to teach kids some basic chemistry, and all you need are some ordinary household supplies. 

Sometimes called the "marshmallow experiment," the process of making foam is a favorite with kids and a whole lot of fun for everyone watching.

There are a few variations on this popular science demonstration.  Some use concentrated hydrogen peroxide (a 30% solution) for very dramatic results, but this concentration is difficult to obtain unless you're a chemistry teacher. 

Highly concentrated hydrogen peroxide can also be dangerous, and working with it requires safety equipment and a variety of precautions. 

So, we'll discuss how you can make elephant toothpaste in a way that's safe for kids and not at all dangerous, provided everyone wears safety glasses.  Simply use a 3% solution of hydrogen peroxide instead of 30%. 

The results won't be quite as dramatic but they'll still be very impressive, and it's much safer than using 30% peroxide.

How to Make Foam

First, we'll describe the process of making elephant toothpaste and how it works. 

At the end of this article we'll give you detailed, step-by-step instructions so your kids can make their own elephant foam (with some minimal adult supervision) and learn a little science at the same time.

Basically, making elephant foamy toothpaste involves mixing hydrogen peroxide with liquid soap and then adding a catalyst (yeast or potassium iodide, for example) to make the hydrogen peroxide quickly break down into oxygen and water. 

This rapid breakdown of peroxide releases oxygen, which is quickly pushed out of the mixture's container.  And, as the peroxide is breaking down into oxygen and water, the liquid soap in the mixture combines with the water that is produced and becomes foamy. 

The oxygen gushing out of the container carries millions of tiny soap bubbles along with it, producing a rising column of foam that kids like to call "elephant toothpaste."  Many people add food coloring to the mixture before adding the catalyst, because the colored column of foam that results resembles toothpaste even more closely.

The key to this fun science experiment is making the hydrogen peroxide break down into its constituent oxygen and water molecules as quickly as possible.  The catalyst speeds up the breakdown process. 

How Does it Work?

As mentioned earlier, the peroxide releases a large amount of oxygen as it is breaking down, and the more highly concentrated the peroxide, the more oxygen it will release. 

This is why science teachers often make elephant toothpaste with a concentrated 30% hydrogen peroxide solution - the chemical reaction is very dramatic because so much oxygen is released. 

However, 30% peroxide is difficult to find and dangerous to work with.  It should only be used while you're wearing safety goggles, gloves and other protective equipment. 

The 3% hydrogen peroxide you can buy in grocery stores and pharmacies is much more dilute and safer to work with.

Hydrogen peroxide (H2O2) basically consists of water molecules (H2O) with an extra atom of oxygen (O) attached.  Making elephant toothpaste is a great way to teach kids how substances can be broken down into their constituents with the assistance of catalysts. 

And, it's messy, with foam flowing up out of the container and going everywhere, so you know kids have a lot of fun watching it!

Kid-Safe Elephant Toothpaste "Recipe"

You'll need the following materials:

  • One 16 ounce empty plastic soda bottle, preferably with a narrow neck
  • ½ cup 3% hydrogen peroxide (you can buy this at any drugstore or grocery store if you don't have some already)
  • Liquid dishwashing detergent (one squirt is all you'll need)
  • A few drops of food coloring
  • One packet of dry active yeast dissolved in about two tablespoons of warm water
  • A funnel

  • A foil pan with fairly high sides

  • Safety glasses or goggles

Add the food coloring to the hydrogen peroxide.  Then, after you put on the safety glasses, stand the plastic bottle in the middle of the foil pan. 

Use the funnel to pour the peroxide into the bottle.  Squirt some dishwashing liquid into the bottle, add the yeast, remove the funnel quickly and then stand back and watch the foam erupt! 

The catalytic action creates foam that shoots up out of the bottle and resembles toothpaste being squeezed out of its tube. 

The foam consists of soap and water with oxygen bubbles, so it's safe for kids to play with.


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