Elephant Toothpaste

Please read the procedure before beginning! After reading, please watch the video. Some activities require more time and clean up than others. You also have the choice of performing these activities in a way that suits your needs.

Materials

· Safety glasses

· Tall-neck bottle of 6% hydrogen peroxide

· Cup of dish detergent

· Vial of food coloring

· Paper cup

· Warm water (not included)

· Tablespoon

· Yeast packet

· Tongue depressor

Procedure

Wear the provided safety glasses for the duration of this activity.

1. Be sure to do this activity on a surface that is easy to clean—a sink, washable tray, or disposable box is ideal.

2. Remove the lid from the tall-neck bottle. Do not spill or remove any liquid from the bottle—this liquid is 6% hydrogen peroxide, which can be a mild skin and eye irritant.

3. Carefully pour the food coloring and dish soap into the bottle.

4. Add 3 teaspoons of warm water to the paper cup. Add the yeast and stir with the tongue depressor for 30 seconds.

5. Quickly add the yeast mixture to the bottle to create elephant toothpaste! Stand back, as the bottle will overflow like toothpaste being squeezed from a tube.

6. Clean up by throwing out your disposable container or washing your foam down the drain! The foam is just dish soap, water, and oxygen, so it is safe to touch.

Science Behind it!

The elephant toothpaste is created due to a chemical reaction between the yeast and the hydrogen peroxide. Yeast are tiny living things, and all living things contain an enzyme called catalase, which acts as a catalyst for hydrogen peroxide (H₂O₂) to break it down into water (H₂O) and oxygen (O₂). The oxygen fills the bubbles in the dish soap, making it foamy! The foam and bottle feel warm because this is an exothermic reaction.

Chemical reaction – a process in which something is changed into something else

Enzyme – made by living organisms to act as a catalyst for chemical reactions within them

Catalyst – something that causes or increases the rate of a chemical reaction

Exothermic – the release of energy as heat

Try repeating the experiment using the same materials, but replace the 6% hydrogen peroxide (20 volume hair developer) with 3% pharmacy hydrogen peroxide. What is different about this reaction? All living things contain catalase, even us! This is why 3% hydrogen peroxide bubbles when used on a cut or scrape—the oxygen produced kills the germs to keep the cut clean.