Death-by-9-Volt Possible?

Though unconfirmed, the accompanying technical explanation of this ancient Darwin Awards winner gives it a measure of believability. The story goes that a curious sailor, having determined the electrical resistance of his skin, attempted to discover the resistance of his blood… by jamming the ends of a multimeter’s probe, powered by a 9-volt battery, into his thumbs. He was killed, they say, when 90mA of current skipped across his heart.

A purported Navy petty officer explains:

How, you might ask, with only a 9V battery? Easy. One of the “rules of thumb” that the Navy teaches is the 1-10-100 rule of current. This rule states that 1mA of current through the human body can be felt, 10mA of current is sufficient to make muscles contract to the point where you cannot let go of a power source, and 100mA is sufficient to stop the heart. Let’s look at Ohm’s law. Ohm’s law (for DC systems – I will not discuss AC here) is written as E=IR, where E is voltage in volts, I is current in Amps, and R is resistance in Ohms.

When we did the experiment in the electrical safety class to determine our body’s resistance, we found a resistance of 500K Ohms. Using 9V and 500K Ohms in the equation, we come up with a current of 18 microAmps, below the “feel” threshold of 1mA. However, removing the insulation of skin from our curious sailor here, the resistance through the very good conducting electrolytes of the body is sharply lower. Around 100 ohms, in fact, resulting in a current of 90mA – sufficient to stop our sailor’s heart and kill him.

Ohms and amps make my brain’s balls hurt, so I’ll buy his explanation with no further analysis. But I have to ask: Why aren’t more people wiring up 9-volts to a pair of sharp wires and killing people by jamming the points into the skin? Seems like a pretty good weapon. Hell, you could lash it to the end of a spear. (I hope I haven’t just prompted a rash of 9-volt killings.)

Resistance is Futile [DarwinAwards.com]