Hi, I am working on this project that has to involve physics, chemistry and biology. The chemists in my group will be performing an experiment to measure the enthalpy of combustion of three different fuels: alcohol, diesel and petrol. My task as a physicist is to, using their results, measure the efficiency of the fuel. I've never learned this in class so I am a bit lost... I have to work with the energy I put in and the energy given out when burning the fuel. (The experiment is like this one: http://www.ausetute.com.au/heatcomb.html) I have no idea if any of this is correct, but this is what I thought: So, the energy put in would be the heat energy from the flame and the energy released I could find by checking by how much the temperature of the water increased, and then use the Specific Heat Capacity calculation? I don't know... I am a bit lost. Can anyone please help me/point me in the right direction? Thanks.