We are all used to the term ‘counting the calories’, but what does it actually mean? A calorie is a measure of the potential energy available from the chemical reaction of a substance. We are used to using the term calorie to identify the fat content of a food, this is simply due to the fact that the greater amount of fat present, the more potential energy, or calories are available. The calorie has been replaced in the UK by the joule as the unit of energy, with 1 calorie being about 4.2 joules.

Fyling Hall’s Year 12 chemistry pupils have been investigating energy changes, or more correctly called enthalpy changes, of a range of chemical reactions. Take a look at Archie investigating the enthalpy change for the reaction between zinc and copper sulfate solution, i.e. counting the calories.