Paper or a lid to cover the beaker
Place the steel wool in one of the beakers.
Pour vinegar on the steel wool. Allow it to soak in the vinegar.
Remove the steel wool from the beaker and strain the excess vinegar
Wrap the steel wool around the base of a thermometer and place it in the other beaker in such a way that the markings on the thermometer is still visible.
Cover this beaker with a paper/lid to ensure that the heat stays in.
Keep making a note of the increase in the temperature in the beaker, every few minutes.
How does it work?
The temperature in the beaker rises gradually and the beaker may even begin to become foggy. When the steel wool is soaked in vinegar, the protective layer on the steel is removed, allowing the iron in the steel to rust. Rusting is a reaction between iron and oxygen which creates heat energy. Since the beaker is closed, it increases the temperature in the beaker, making it foggy. The reaction between steel wool and vinegar is called ‘exothermic reaction’ as this results in the release of heat.
Burning of fuel or lighting of a candle are few other examples of exothermic reaction.