Q&A for How to Make Elephant Toothpaste

Making elephant's toothpaste is a fun way to show kids how a chemical reaction manifests itself in physical products/changes.

The chemical formula for hydrogen peroxide is H2O2. As it decomposes, or breaks down, the two molecules of H202 separate into two liquid H2O (water) molecules and a single oxygen molecule. These spare oxygen molecules then bond, forming O2 (gas) molecules, the rapidly forming bubbles of oxygen that rise to the surface of the solution. Without the hydrogen peroxide there would be no bubbles and no foam.

No, you can use 3% or 6% H2O2 instead. The only drawback is that the reaction will be slower and more catalyst may need to be used.

After concentrated hydrogen peroxide is mixed with a soapy liquid, a catalyst (a substance that starts or speeds up a chemical reaction) such as potassium iodide or manganese dioxide is added to rapidly break down the hydrogen peroxide into water and oxygen.

No, you will not be able to do this without hydrogen peroxide. The point of this whole experiment is to show the decomposition of hydrogen peroxide. It shows it turning into water and oxygen gas.

You need a catalyst in order to make the reaction happen fast enough. A catalyst is a substance that increases the reaction speed. The hydrogen peroxide will decompose on its own, but it won't make an effect. So if you decide to do the homemade version, you need yeast; if you do the lab version, you need the potassium iodide.

Yes, you can add different colors and not mix it. If you mix it, it will become brown.

Put the materials in separate, handled plastic bags and carefully carry them to school.

It's quick, just a couple of minutes to get everything started and a minute or two for the reaction to start. No longer than 10-15 minutes, 20 with cleaning.

Nothing special. It's a fun experiment that kids (and adults) love. It's fun to see the foam rise, and you can even make it into a fun show (there are some cool videos on YouTube). It's a nice and easy experiment that can help kids get interested in chemistry.

No, dish soap is required to dissolve the peroxide.

The foam only contains soap, water, and oxygen, so the foam should be disposable. If you used yeast, then you're fine, but potassium iodide might be harder to dispose of.

Use a hose to wash out of grass or do this experiment a day before a thunderstorm.

Yes, you can, but the tube needs to have a narrow opening at the top, because the result will be powerful.

You can buy 30% hydrogen peroxide from a beauty store.

Preferably you should use glass, but if that's not available, then plastic is fine.

The name "elephant's toothpaste" comes from the appearance of the foam since it looks like a huge volume of toothpaste.

A glowing wood splint is a match, or any other source of wood that has been ignited.

1/2 cup 20-volume hydrogen peroxide liquid (20-volume is a 6% solution, which can be found at a beauty supply store or hair salon).

Do the experiment on a large tray. Wipe down any foam that got off the tray with a damp rag.

The dish soap captures the oxygen produced from the breakdown of hydrogen peroxide. As more and more oxygen is produced, the soap begins to form billions of bubbles and pours out of the container as foam.

Yes. The only drawback is that the reaction will be slower and more catalyst may need to be used.

There is only so much hydrogen peroxide in the reaction. Once all the H2O2 has broken down to H2O and oxygen gas, it doesn't matter how much yeast you add. Now, if you added more hydrogen peroxide, you might get more reaction.

30% is the volume of hydrogen peroxide in the overall bottle that you purchase. It is a solution of water, hydrogen, peroxide, and phosphoric acid, of which 30% is hydrogen peroxide. It has nothing to with pounds, but rather a concentration level.

Yes, but be cautious because it will produce a lot of foam.

A glowing wood splint is a matchstick that has been lit, or possibly a thin piece of burning wood.

It can actually leave a small, itchy burn, but nothing more. It won't be dangerous.

No, because it will decompose the bottle.

It can. There are limiting factors. You could add a gallon of yeast, but if there is only half a cup of hydrogen peroxide (H2O2) you won't use all the yeast. The opposite is also true. If you had a gallon of H2O2 and only a pinch of yeast, you wouldn't get the same reaction. The trick is finding the perfect balance.

Yes, it’s very hot. Wear rubber gloves and don’t touch it, as it might burn your skin.