I'll try. Some have done a decent job here already. Watts = volts * current (amps). It's hard to compare words like "force" and "quantity" for volts and amps

I'll try. Some have done a decent job here already. Watts = volts * current (amps). It's hard to compare words like "force" and "quantity" for volts and amps, but here's maybe a practical definition. High voltage is dangerous because it can leap through air (arc) to form a circuit. If part of that circuit is _you_ (like, from a high-voltage wire, through you, to the ground), then you can be made dead, quite quickly. That's why high-voltage (sometimes called "high-tension") wires are carried by tall towers with the wires far apart -- if the wires were closer together, they could arc between them and short out. Essentially, high voltage overcomes insulation -- whether the insulation is air (for high-above-ground wires) or various forms of plastic (for wires buried underground). That's what makes it dangerous, and why electrical panels have warnings that say "Danger: High Voltage". But even very high voltage won't hurt you if the current (amps) is too low. But "low current" isn't something you typically encounter in, for example, household AC wiring because the supply of current is generally very large. So high voltage can kill you, but only if the current (amps) is high enough. In most practical situations where you might be exposed to electricity from the grid, the current is plenty high. That's why the signs say "Danger: High Voltage" and not "Danger: High Amps" or "Danger: High Power" (watts). But how high is "high"? A 12-volt car battery (I wonder how long that term will be meaningful...) isn't very high voltage. You can safely put your dry fingers across the terminals of a 12v battery and not feel a thing. On the other hand, the 120-volt (or 240-volt) electricity coming out of a wall socket is most definitely unsafe to grab with your dry fingers. I've been accidentally shocked dozens of times by 120v electricity, and it is attention-getting. It can kill you fairly easily if, for example, the alternating current of the electricity causes your muscles to contract, forcing you to hold on ever more tightly to the wires. Usually, it's your heart in the path of the current that takes the, um, beating. If you get a shock across just the one hand that you're sticking accidentally into a live electrical box, your tendency is to retract your arm. Very quickly. But even 120 or 240 volts won't jump across very much air, like, essentially, none. Compare that to the 100,000+ volts that are carried by the high-tension lines at the top of int[er|ra]state transmission lines -- that's enough voltage to arc across many inches of air without any trouble at all. So why do we use high voltage at all, why can't we just use low voltage everywhere and be safer? That's where the magic of the power equation (Power (watts) = Volts * Amps) comes in. But that's for another discussion.