In this activity, students will use chemical reactions to create toothpaste big enough for an elephant! (It’s not really toothpaste, so please don’t eat it.)

Materials Needed

Per Group (1-3 students):

16 oz. empty plastic soda bottle (preferably with narrow neck)
½ cup hydrogen peroxide (higher concentrations produce more foam)
Squirt of Dawn dish detergent
3-4 drops food coloring
1 tsp yeast
2 Tbsp hot/very warm water
Funnel
Foil cake pan with 2 inch sides

Optional (One per Student):

Lab smock or apron (Some food coloring stains clothes)

Steps:

Have kids don lab smocks. (If applicable)
Dissolve yeast in very warm water.
Place bottle in foil pan.
Using the funnel, carefully add hydrogen peroxide to the bottle.
Add 3-4 drops of food coloring to the bottle.
Squirt some dish detergent into the bottle.
Add the dissolved yeast and quickly remove the funnel.
Observe what happens, visually and by touching the bottle.

Explanation:

The hydrogen peroxide we used is fizzing with bubbles. Just like soda, if you leave it out for long enough, it goes “flat.” When this happens, the peroxide is letting go of one of its oxygen molecules, turning it into water.

The yeast in the solution acts as a catalyst. That means it is something that makes the chemical reaction occur faster. That makes the peroxide molecule (in the hydrogen peroxide) release the oxygen atom faster. We call this an exothermic reaction, which means it makes heat. That’s why the bottle feels warm.

Real Life:

One example of a common catalyst is found in cars. The nasty black smoke that comes from cars is called exhaust and it is really bad for the environment. Scientists realized this a while ago and created a catalytic converter as a solution. This converter uses a catalyst to break down some of the harmful chemicals so the exhaust isn’t as gross.

Adapted from Fantastic Foamy Fountain by Science Bob