how well does water conduct electricity? do people really die when they drop toaters in the bath?
Water does not conduct electricity especially well. When there are impurities in water, like natural minerals and stuff in tap water, or salt in oceans, it becomes a slightly better conductor.
If you’re in a bathtub, the drain pipe makes an excellent ground.
I don’t know of any statistics regarding accidents; any modern building will trip a circuit when it shorts to ground so you’re not likely to die.
Back in the day, however, it was probably a more common occurrance.
Not to nit-pick, but as far as I know, pure water doesn’t conduct electricity at all.
Then, the minute you add something like a salt (any salt’ll do- not just sea or table salt) it becomes a very good conductor. (depending on the amount of ions in the water, of course)
Pure water is a rather poor conductor of electricity. The conductivity of a liquid can usually be determined by the concentration of ions present in solution. For pure water, the total concentration of ions (H[sub]3[/sub]O[sup]+[/sup] and OH[sup]-[/sup]) is 2 x 10[sup]-7[/sup] Molar. (equal parts of each ion).
Tap water is a fairly good conductor of electricity because it contains dissolved salts. For example, tap water containing 100 parts per million of dissolves salts has an ion concentration of 0.011 Molar, an ion concentration that is five orders of magnitude greater than that of pure water.
What water does do is greatly decrease your body’s contact resistance, making it more likely that you will suffer injury in the event that you do become part of an eletrical circuit. The bathtub itself doesn’t make this much more likely, since most tubs are either porcelain coated or made from some kind of polymer. But as friedo has pointed out, the conductive metal fixtures are right there in front of you, and I can imagine that the first thing some hapless person might do when startled by a submerged hair dryer would be to grab hold of the metal fixtures in a hurried attempt to exit the tub. With a modest amount of electrically conductive water between you & the hair dryer, all you need to do to complete the circuit is grab hold of the fixtures.
I estimate that you’d draw several milliamps at least, which is enough to make you muscles contract violently. Death would probably result from banging your head on the tub or drowning.
Normal contact resistance varies widely depending on the relative dampness of the skin. This can be easily demonstrated by holding the leads of an ohmmeter with dry hands, and again with slightly damp (moisture from your breath is more than enough) hands. The change is something like 100:1, dpeending on a few other factors like how hard you grip the test leads. And yes, pure distilled water is one of the best insulators, but by the time you’ve gotten your hands wet, we’re no longer dealing with pure water. The dried salts on your skin are sufficient to make a reasonably effective electrolyte.
In fact, one of the body’s first natural reactions to danger is to make itself a better conductor of electricity.
If you’ve come upon an unfortunate victem of bathtub electrocution, be sure to visit this thread where we’ve been trying to determine if it’s possibly to insulate a body against electrocution.
What I want to know is who in the hell eats toast while bathing?
–Tim
“But I like to eat [toast] in the tub” said the cat. “You should try it sometime” said the Cat in the Hat.
So, if salt water is a good conductor of electricity (or at least better than pure water), then what the deal when lightning strikes the ocean? If someone is swimming in the ocean, how far away does s/he have to be to not get electrocuted?? On a smaller scale, what about electric eels?
Lightning striking water will have a dispersing effect. The shock spreads out, so the intensity fades with distance. You typically get a spherical shaped charge zone, the closer to the strike the more danger. I’m not sure the actual distances.
Same thing with electric eels, I imagine.
The links I found on google all say they can make up to 650 volts, but nobody talks about range of effect.
Attrayant said: " Death would probably result from banging your head on the tub or drowning."
Actually death would be more likely to occur because the frequency of the alternating current (60 Hz) tends to disrupt the natural rhythm of the heart and causes it to beat in a rapid and ineffectual manner. In the right circumstances, only about .006 amps is required to cause this.