Where Do Elephants Pack Their Toothpaste? In Their Trunk!
This demonstration’s called Elephant’s Toothpaste because the chemical reaction produces a large foamy mess that looks like toothpaste squirting out of a tube. It is so big that only an elephant could use toothpaste this large. It is, of course, not
toothpaste so please do not try to brush your teeth with it! The kids-safe version below is harmless but certainly wouldn’t taste very good.
- Baking soda
- CO 2
- H 2 O
- O 2
- H 2 O 2 ,
Hydrogen peroxide – 6% if possible. 3% (what is sold in drug stores) will give off a smaller reaction
Liquid watercolor or food coloring (optional)
Medium-sized soda bottle (empty)
Tiny scoops & spoons (about ¼-ish teaspoon) + a Tablespoon measure
Tub of water/sink close-by
- Before you do anything, put the soda bottle on a baking tray or large bowl.
- Mix 1 Tbsp yeast into 3 Tbsp of warm water in a small paper cup. Consistency should be that of melted ice cream. Set aside to get all bubbly and happy (as yeast and warm water always do)
- Using the funnel, carefully pour about ½ cup of the Hydrogen Peroxide into the soda bottle
- Add some liquid watercolor (optional)
- Add about 1 Tbsp of dish soap to the Hydrogen Peroxide
- Use the funnel to pour the yeast mixture into the bottle, then step back.
When hydrogen peroxide breaks down, it turns into oxygen (O 2 ) and water (H 2 O). Normally this breakdown happens very slowly. But the reaction could be done faster by adding a catalyst. Yeast is an organism that contains a special chemical called catalase that can act as a catalyst to help break down hydrogen peroxide. Catalase is present in almost all living things that are exposed to oxygen, and it helps them break down naturally occurring hydrogen peroxide.
This means that if you mix yeast with hydrogen peroxide, the hydrogen peroxide will rapidly break down into water and oxygen gas. The oxygen gas forms bubbles. These bubbles would usually escape from the liquid and pop quickly. But, adding a little dish soap provides additional surface tension, allowing the bubbles to get trapped and creating lots of foam. This foam looks like a giant squeeze of toothpaste—almost big enough for an elephant!
Because this reaction is exothermic, the bottle and the foam will be warm.