Summer is the perfect time to get outside and do some messy science with the kids. This week we had tons of fun making super foamy elephant toothpaste.
- A Clean 16 oz. Plastic Bottle
- Liquid Dish Soap
- 1/2 Cup Hydrogen Peroxide (for best results use 6% but 3% will work)
- 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 on Amazon.
We couldn’t wait to give it a try, so we used the standard peroxide we had in the medicine cabinet. Although the reaction wasn’t as extreme, we were not disappointed with the results.
Creating your own hydrogen peroxide and yeast reaction is simple. It can also get messy. This one is best done outside, where it can be cleaned up easily with a hose.
Begin by squeezing 7-8 drops of food coloring into your plastic bottle.
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 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.
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 produces foam, it also causes an exothermic reaction — it produces heat.
The foam is safe to touch, and if your kids are anything like mine, they will find it hard to keep their hands out of it. They spent a good 15 minutes playing in the foam.
Take this kids activity to another level with the extensions below.
- 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?
- Does the reaction still work if you don’t mix water with the yeast before adding it to the soap mixture?
Kids love messy science experiments. Elephant toothpaste is the perfect foamy fun for summer.
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