Let's use some household materials to create a chemical reaction that we can see and feel!
12% Hydrogen peroxide (also called 40 volume at beauty supply stores)
Narrow necked container or Erlenmeyer flask
Safety glasses and gloves
Optional glitter or food coloring
Mix 1 tablespoon of the yeast with 3 tablespoons of warm water in the small glass.
Place your narrow-necked container or Erlenmeyer flask on the tray.
While wearing gloves and safety glasses, pour 1/2 cup or 120 mL of hydrogen peroxide into the narrow-necked container or Erlenmeyer flask.
Add a few squirts of dish soap and any glitter/food coloring you would like into the hydrogen peroxide.
Pour the yeast and water mixture into the hydrogen peroxide and watch what happens.
Try putting your hand near the reaction without touching it, do you notice anything?
Reflect on this activity and extend it:
What has happened? Hydrogen peroxide has the chemical formula of H2O2. This means that when it breaks down it becomes O2 and H2O; you might know those better as oxygen and water. What happens when we mix oxygen, water, and soap? We make bubbles. But why does it bubble so much? In this reaction, the yeast acts as a catalyst - something that sparks a reaction. The yeast causes the hydrogen peroxide to break down so quickly that it makes foam so large and fluffy that it almost looks like toothpaste for an elephant!
Why is it hot? This reaction is something called an exothermic reaction meaning that it is a reaction that releases heat!
How can we change this reaction? Try adding some water to the hydrogen peroxide before adding the yeast, does this change the reaction? can you add so much water that the reaction doesn't happen?
You can download a printer-friendly version of this activity below!