Elephant toothpaste is a perfect experiment to explore decomposition and exothermic reactions! Decomposition is a word we use when something breaks down. When a chemical reaction occurs and it releases heat, we call it an exothermic reaction. Follow the experiment below to discover how to make your own chemical reaction that both decomposes and lets off heat!
- 1/2 Cup Hydrogen Peroxide (3% - found in first aid supplies)
- 1/4 Teaspoon Dish Soap
- 1/2 Cup Warm Water
- 1 Teaspoon Active Yeast
- Flat Easy-to-Clean Surface
- Empty Plastic Bottle
- Food Coloring
- Small Funnel
1. Pour 1/2 cup hydrogen peroxide, soap, and a few drops of food coloring into the bottle.
2. Gently swish the bottle around to mix the ingredients. Set the bottle some place where you won't mind getting wet foam everywhere (tray, tablecloth, sink, or outdoors!)
3. In a separate container, pour a tablespoon of active yeast with 1/2 cup warm water.
4. Using a spoon, mix the yeast and warm water together! Wait a few minutes for the yeast to activate!
5. When you are ready, pour the yeast mixture into the bottle. A reaction occurs
immediately upon the addition of the yeast, so make sure you move out of the way!
6. Play with the foam and admire the beautiful exothermic reaction!
What happened? Hydrogen peroxide – H2O2 – is a very special chemical. It is just like water – H2O – but it has one extra oxygen atom. This extra oxygen causes the chemical to be very unstable, meaning it wants to give the extra oxygen away and decompose. It lets off this oxygen as a gas but sometimes it can be hard to see, so we add in soap to catch the oxygen in bubbles. Normally this happens very slowly, but we added a catalyst which makes the reaction happen a lot faster. Our catalyst for this experiment is yeast! When the extra oxygen breaks off from the hydrogen peroxide, all of the energy used to hold the two together is released and lets off heat, causing an exothermic reaction.