Chemical Cells And Fuel Cells C

Somewhere in the room you are sitting in there is almost certainly a small sealed cylinder that is quietly eating itself. A cell in a torch, a remote control or a smoke alarm works by letting one metal corrode on purpose, in a container built so that the electrons released have nowhere to go except the long way round, through your circuit. That is the whole trick of a chemical cell: take a reaction that would otherwise waste its energy as heat, and force the electrons to do a job on their way from one reactant to the other.

It also explains the one thing everybody knows about batteries, which is that they go flat. The reactants are sealed inside, there is a fixed amount of them, and when they run out the voltage collapses. This lesson takes that limit seriously and then shows you the engineering answer to it: a cell you never charge and never throw away, because you pipe the reactants in from outside as fast as it uses them. Hydrogen goes in, air goes in, electricity comes out, and the exhaust pipe drips water.