Objectives

 To demonstrate how yeast can act as a catalyst to release oxygen

Materials

• Plastic empty soda bottle (16 ounce), preferably with a narrow neck
• 40-volume hydrogen peroxide (available at beauty supply stores)
• Dish detergent (we prefer Dawn®)
• Food coloring (any color but red and yellow if you want to make Halloween orange)
• Small cup
• Dry yeast (fast acting works best—check the expiration date!)
• Water (not boiling, but very warm)
• Measuring cup
• Tablespoon
• Teaspoon
• Funnel (or just be careful pouring)
• Foil pan with two-inch sides
• Wooden craft stick (or something for stirring)

Procedure

Place the bottle in the center of the foil pan. Place the funnel in the bottle opening. Pour one-half cup of hydrogen peroxide into the bottle. Add three drops of food coloring to the hydrogen peroxide. Add a squirt of dish detergent to the mixture too. Dissolve one teaspoon of yeast in two tablespoons of warm water in a separate small container. Pour the mixture into the bottle and quickly remove the funnel.

Conclusion

The reaction creates foam that shoots up out of the bottle and flows into the pan. Hydrogen peroxide is made up of two hydrogen atoms and two oxygen atoms (H₂O₂). The yeast acts as a catalyst. When you pour the yeast into the hydrogen peroxide, you are releasing oxygen atoms. The bottle and bottom of the pan will feel warm due to the exothermic reaction (chemical reaction that produces heat).