May 26th, 2024

Science Smarts: For a longtime special helper

By Patty Rooks on May 4, 2024.

Today’s article is particularly special as I am dedicating it to one of my biggest fans – not to mention biggest helpers – over the years. If there was an event to prepare for or go to for Praxis he did not have to be asked twice, often coming up with ideas to share his love of STEM with others as well.

I reached out to him and asked what his most favourite experiment was that he did with me all these years was and trust me, there were a LOT of experiments over the years. But this is his favourite. I may even have to do the “adult” version with him next time he is home. Let’s get started!

*An adult needs to do this experiment with you.


– Food colouring

– Package of yeast

– Warm water

– Measuring spoons

– Measuring cups

– Empty cup

– Stir stick or spoon to stir with

– Large plastic flask or empty large soda bottle

– Peroxide

– Dish soap

– Safety goggles

– Baking pan

– Flat empty counter or table to work on


1. Find a good place to work as this experiment could potentially make a mess! Outside would be perfect or a good sturdy counter will work, too.

2. Put on your safety glasses.

3. Place the flask on the cookie sheet and set aside for now.

4. Measure three tablespoons (45 mL) of warm water into the empty cup.

5. Measure one tablespoon (15 mL) of dry yeast to the warm water. Stir it well and set aside for a minute or so.

6. Measure ½ cup (125 mL) of hydrogen peroxide and carefully pour it into the flask.

7. Add a few drops of food colouring of your choice. Swirl it around.

8. Squeeze three large squirts (I know such an exact measurement, but it does not need to be precise) of dish soap into the peroxide mixture.

9. Have everyone stand back and slowly add the yeast mixture to the peroxide mixture.

10. Watch what happens.

11. Clean up your mess!!


I call this experiment elephant toothpaste because it looks like toothpaste being squeezed out of a tube and big enough for an elephant to use – it should foam up and squirt right out into the air!

There is a bit of a complicated chemical reaction occurring in this pretty cool experiment! Let us look at this simply. Basically, you start with peroxide and a bit of soap. You add a catalyst to this mixture. As a result of this you start breaking down the peroxide into two of its components; oxygen and water. What you end up with is water and soap and a TON of tiny bubbles as a result of the oxygen being released.

Did you know you should read the percentage of peroxide you use as there are varying strengths – 3%, 12% and even higher? Look around at different stores to see what you can find. The stronger the peroxide, the larger your reaction! Be careful though, and follow all safety rules to keep your science fun and safe.

Patty Rooks, senior scientific consultant PRAXIS, “Connecting Science To The Community.” Contact Praxis at,, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: 12 826 11th Street SE, Medicine Hat, AB, T1A 1T7 Phone: 403-527-5365, email:

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