Science Buddies: "Ask an Expert"

hey,
Have read the
https://www.sciencebuddies.org/science- ... able-fuels
and have a few queries.

1) How do you calculate the energy input for the fuel, for calculating energy efficenciy. I know how to calculate energy output but no sure for input.
2) Why do you need record the time taken when the fuel is burning.

Thank you

Hi matcha,
In regards to you question 1, can you help clarify what you are looking for in the energy efficiency calculation please?
In this particular experiment, all of your "energy" is "captured" in the changes of the water temp. Since it is the same setup / mechanism for heat transfer, we would expect the efficiency to be the same independent of the fuel.

In regards to your second question, I believe the time can help show you the rate of the heat transfer. For example, if one of the fuel burns hotter, you would expect that it would take less time to heat up the same volume of water.

I hope that helps. Please post again if you have any other questions.
Willey