Kid Science: Elephant Toothpaste

As much as I love the summertime and the sunshine and letting my kids play outside, there comes a point every day where it's just too hot and we have to come inside and cool off. I made a commitment to myself that I would try to have a balance between structured time and unstructured time this summer, but I haven't been doing as well on the structured time with my kids as I would like. So at the beginning of the week, I decided to do a little experiment that I've had on my mind for the last little while, but hadn't gotten around to: elephant toothpaste.

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Like many kids, mine love anything that bubbles and foams. We've done glow in the dark bath paint, bubble snakes and color explosions and they have all been winners. This experiment only required me to buy one thing I didn't already have on hand (hydrogen peroxide), and now I have it so we can do this another day too.

My kids totally oooh'd and aaah'd over this activity and it kept them entertained even after the initial experiment was over. We did it a couple of times--once with my daughter while my son was napping and then again when he woke up.

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To make your own elephant toothpaste, you will need the following:

6% (20 volume) hydrogen peroxide (also known as developer in a beauty supply store)
dry active yeast
water
liquid dish soap (not antibacterial, such as Dawn)
food coloring (optional)
an empty water bottle (about 16 oz)
a funnel

First, measure 2 Tbsp. very warm water into a small bowl. Add 1 tsp. active dry yeast (1/2 packet) and stir around. Make sure your water isn't too hot or you'll kill the yeast. You can have your child help with this part.

Set your water bottle in the middle of a 9x13 pan. Using the funnel, pour 1/2 c. hydrogen peroxide into the bottle. Add 4-5 drops of food coloring and a couple squirts of dish soap. Swirl it together gently. I wouldn't recommend having your child do this part unless you feel confident they won't spill or lick their fingers if they get stuff on them.

Pour the yeast into the bottle through the funnel. (Again, something your child could do.) Remove it quickly as the reaction will start right away and enjoy the crazy foam!

A few things:

The foam is totally safe to touch! The peroxide gets broken down in the reaction, only leaving water and oxygen behind.
The reaction is exothermic, which means it gives off heat. You can have your child touch the bottle and they will feel the warmth. Pretty cool!
6% (20 volume) hydrogen peroxide is a bit of a specialty item, which you can buy at any beauty supply store (or order it online on Amazon by clicking the link). The kind you buy at the store is only 3% and it will still produce a reaction, but it won't be nearly as impressive.

After the reaction slowed down, I brought out some little cars and plastic animal (one was an elephant of course) and let them play in the foam. I had to take it away before they were actually done playing in it because their hands were starting to turn colors. ;)