Like so many boys, my son absolutely loves making things explode.
The tricky part is finding ways to have that excitement and still be safe.
Thank goodness for fun, messy science activities, like our soda pop geyser.
Our latest messy science activity was this kid friendly Elephant Toothpaste Experiment.
The chemical reaction in this experiment is often referred to as “elephant toothpaste” because when it foams out of the mouth of the bottle it looks a lot like when you squeeze toothpaste out of a tube. Some joke that if it were really toothpaste, it would be the amount an elephant would need.
Obviously, since liquid dishsoap is used, it should NOT be ingested.
Your child may also like some of these STEM activities for kids.
Elephant Toothpaste Experiment Materials
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- A Clean 16 oz. Plastic Bottle
- Liquid Dish Soap
- 1/2 Cup Hydrogen Peroxide
- 1 Tablespoon (one packet) Dry Yeast
- 3 Tablespoons Warm Water
- Food Coloring (optional)
- Small Cup
For the ultimate reaction, which can produce foam that shoots 5 or more feet into the air, you need to use what’s called 20-volume (or 6%) hydrogen peroxide. This peroxide is stronger than what you find at the grocery store. In the U.S. you can find this at hair salons or online.
We couldn’t wait to give it a try, so we used the standard 3% peroxide we had in the medicine cabinet. Although the reaction wasn’t as extreme, we were not disappointed with the results.
How to Make Elephant Toothpaste
Like I mentioned earlier, this experiment can get messy. It is best done outside, where you can clean up easily with a hose.
Begin by squeezing 7-8 drops of food coloring into your empty plastic bottle. This step is completely optional, but the color does make the reaction even more fun to watch.
Add 1 tablespoon liquid dish soap and swirl the bottle around to mix it with the food coloring.
In your small cup combine the warm water and yeast together and stir for 30 seconds.
Use the funnel to quickly pour the yeast mixture into the bottle.
The reaction will start almost immediately.
If you use the 6% hydrogen peroxide it can shoot several feet into the air, so be sure to get out of the way quickly.
How Does Elephant Toothpaste Work
Yeast contains an enzyme called Catalase. This enzyme breaks down hydrogen peroxid (H2O2) into oxygen gas and water (H2O).
The oxygen gas gets trapped in bubbles made by the dish soap, producing that fantastic foamy solution that erupts out of the bottle.
Once the foamy explosion is finished, you will notice the bottle and foam are warm to the touch. That’s because the experiment not only causes a chemical reaction that produces the foam, it also causes an exothermic reaction — meaning it produces heat as well.
If you use the standard 3% hydrogen peroxide, then the foam is safe to touch. (I’ve heard 6% hydrogen peroxide can cause skin irritation to those with very sensitive skin.)
If your kids are anything like mine, they will find it hard to keep their hands out of it. Mine spent a good 15 minutes playing in the foam afterwards.
More Fun with Elephant Foam
Try some of the ideas below to take your child’s learning even further.
- Does the amount of yeast used change the amount of foam produced? Try using more or less yeast to see what happens.
- What about using more soap? Experiment with different amounts to see what happens.
- Does the reaction still work if you don’t mix water with the yeast before adding it to the soap mixture?
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Originally published June 29, 2017.