I have been learning the concepts of voltage, current, and resistance. I am aware of Ohm's law and have read a lot of materials on it, but none of what I have read addresses a few questions that have been popping up in my head. Many educational sources like to compare the situation to a water pressure system. The problem with that analogy is that with water, knowing how much volume per second is displaced is enough to know how much work that water can do. With electricity however, you must not merely know the flow rate (amps) but must also know at what voltage those amps are! I don't understand why merely knowing how many electrons are traveling down the circuit's line isn't enough. Isn't that all the information you should need? I mean, each electron has a definite charge, and if X electrons are moving down the circuit and they all have this definite charge...why must more be known? The way I've been interpreting it is that voltage causes electron flow which in turn causes power. Yet the way it's presented seems to keep the concept of voltage entangled with the subsequent current, and thus necessary to make calculations regarding power. Which leads to another question I have. If voltage represents the difference in charge from one point to another and thus the electric potential energy, why doesn't voltage decrease over the lifetime of a battery sitting on a circuit? I would imagine all those electrons moving from the negatively charged area to the positively charged area would slowly but surely bring the system to an electric equilibrium, thereby dropping voltage to 0. Yet nowhere do I see this phenomenon mentioned. Does this happen and if not, why not? Thanks for any help.