Hi, for a science project I have, I need to find the energy efficiency of biodiesel and biomass. Does anyone know what that would be?

How do I prove that my biodiesel is different from the vegetable oil from which the diesel was derived? I am making biodiesel for a science project on a very very minimalistic budget (25 dollars). Is there a cheap yet effective way to tell the difference between biodiesel and vegtable oil? I do not have anything that runs diesel in my home. Please exclude things that can be derived locally, unless you know for a fact that this is something that can be found anywhere (i.e. in a supermarket).