Elephant toothpaste is a popular school science project that makes a bottle erupt with a huge stream of colorful foam. It matters because it shows how a chemical reaction can happen very quickly when the right helper is added. Students can see bubbles, heat, and motion all at once, which makes invisible chemistry easier to understand.
Safety goggles, a tray, and adult supervision are important because the foam can overflow fast.
Key Facts
- Overall reaction: 2 H2O2 -> 2 H2O + O2
- Yeast contains catalase, an enzyme that speeds up the breakdown of hydrogen peroxide.
- Dish soap traps oxygen gas and water in bubbles, making the foam column.
- The reaction is exothermic, so it releases heat and the bottle may feel warm.
- Warm water helps wake up the yeast, but very hot water can kill the yeast.
- Use 6% hydrogen peroxide only with adult supervision, goggles, and a tray to catch spills.
Vocabulary
- Hydrogen peroxide
- A liquid chemical, H2O2, that can break down into water and oxygen gas.
- Catalyst
- A substance that speeds up a chemical reaction without being used up.
- Catalase
- An enzyme found in yeast that helps hydrogen peroxide break down quickly.
- Exothermic reaction
- A reaction that releases energy as heat to its surroundings.
- Foam
- A mixture of gas bubbles trapped inside a liquid or soft solid.
Common Mistakes to Avoid
- Touching the foam with bare hands right away is unsafe because the mixture may still contain hydrogen peroxide and can be warm.
- Using boiling water with the yeast is wrong because very hot water can kill the yeast and slow or stop the reaction.
- Forgetting the tray is a problem because the foam can overflow quickly and make a slippery mess.
- Calling the dish soap the catalyst is incorrect because the yeast catalase speeds the reaction, while the soap mainly traps oxygen gas in bubbles.
Practice Questions
- 1 If 50 mL of hydrogen peroxide is mixed with 10 mL of dish soap and 20 mL of yeast mixture, what is the total liquid volume before the reaction starts?
- 2 A group uses 100 mL of 6% hydrogen peroxide. If another group uses half as much, how many milliliters of hydrogen peroxide do they use?
- 3 Explain why the foam rises out of the bottle and why the bottle may feel warm after the reaction.