What You Need:
- Hydrogen peroxide - 12% (available at a chemist)
- Liquid dish soap
- Food colouring
- Package of dry yeast
- Small cup (small enough to fit all the way inside a pumpkin)
- A small carved pumpkin or any other fleshy vegetable (with its base cut off and its insides hollowed out)
- Take the help of an adult when performing this experiment. And remember that it can get a bit messy.
- Fill a small cup with 30ml of hydrogen peroxide (H2O2).
- Add a squirt of dish soap and food colouring to the hydrogen peroxide.
- Place the cup inside the carved vegetable.
- Mix an entire package of dry yeast (10gms) with 4 tablespoons of very warm water in a small plastic cup.
- Pour the yeast solution into the cup and quickly place the carved vegetable on the cup.
Your vegetable will start oozing foam. The catalyst - the yeast solution - reacts with the hydrogen peroxide and leads to the release of oxygen molecules and water. When these molecules pass through the soap, they form foam. In addition to the release of H2O and O2, energy is also released in the form of heat.