- As little Timmy opens his first Christmas present, the sound of excitement fills the room, but the bright red radio control truck doesn't work without its counterpart, the simple D-Cell battery. What exactly makes this small piece of metal so crucial to today's society?
The Science of Portable Electricity
- A D-cell battery, the largest of the zinc-carbon family of batteries, is essentially a storage container for the chemicals inside of its casing. The battery has two terminals, one positive (the nubby end) and the negative (the flat end). Behind the scenes, zinc and carbon plates alternate between an acidic paste which acts as an electrolyte to produce reactions which give off electrons that gather at the negative terminal of the battery, at this point there is no reaction going on.
Let's Get The Juice Flowing!
- Inside a battery.
So how does this piece of metal make Timmy's truck work? The answer lies in the electrons' natural urge to want to go to the zinc plate at the end of the positive terminal--electrons love zinc and will put up with carbon as long as you give them what they want. If you connect a wire straight from the positive to the negative terminal, the battery would wear out faster than you could say banana, so instead we need something to ease the load on the reactions, like a toy truck for instance. As the wire goes from the negative terminal and powers the truck a second wire coming from the truck connects to the positive terminal which activates the chemical reaction inside, thus creating a circuit.
The Death of a D
- Unfortunately, the end has to come sometime. This happens when there is no more zinc in the battery. Each time a reaction takes place, a little bit of the zinc gets eaten away by the electrons, when it's all gone, the battery's had it and it's time for a new one.