Working out energy content in fuels

During the last couple of weeks we have been doing a lot of practical activities based around the energy content of fuels. It is a simple process involving heating water with a flame produced by either burning wax, natural gas or ethanol.

Scientists have found that it takes 4.2 Joules of energy to heat 1ml of water by 1 degree C. So as long as we know how many mls of water we are heating and how long it takes and by how much the temperature increases we can calculate the amount of energy produced per unit of time. If we know also how much fuel was consumed (burnt) for example by weighing the fuel before and after heating the water we can calculate how much energy is produced per gram of fuel. This can be used to compare the energy content of our fuels.

Energy content in ethanol