After another day of copious diligence, you have arrived at the end of this subsection. At this point in time, you comprehend the differences between energy flow and energy flux. While the overall energy may be conserved, you have seen that one type of energy can be converted to others, depending on the circumstances as well. Armed with this knowledge, you’ve applied the First Law of Thermodynamics to compare the contributions of a few different forms of energy to the total energy contained within a mug of hot chocolate.

Up until now, this week has been quite conceptual without a lot of calculations involved. In the next subsection, however, we’ll combine expressions for the various forms of energy, to arrive at a general balance equation for the total energy contained within a system.