It would seem if the charge could enter the blood directly. Blood would then allow it to cross the heart, which could disrupt normal function.
-------------------- "To be or not to be! That is the question! Now, will you answer, dare, double dare, or take the Physical Challenge?" --Mark Summers as Hamlet Countdown: 177 days and counting... or less. My blog. 14 keyboards owed. Posts: 5584 | From: Ohio | Registered: Dec 2003
| IP: Logged |
quote:Originally posted by Casey, proving a circle: It would seem if the charge could enter the blood directly. Blood would then allow it to cross the heart, which could disrupt normal function.
If blood were a really good conductor, and the veins and arteries it travels in were good insulators, yeah, it could be a problem. Fortunately, they're not and not.
Posts: 2079 | From: California | Registered: Feb 2000
| IP: Logged |
I was the youngest of four children. My siblings were 14, 12, and 9 years older than l'il ol' me.
For several Christmases in a row, when my parents would leave the cluttered room of new toys, my siblings would hit the "battery drawer" to power their new transistor radios, walky talkies, and whatever other kind of "grown-up" Christmas prize they had received.
As the youngest, my job was the lick the 9-volts to make sure they were still good. Because they were older and knew more, I never questioned why I would be stuck with this job year after year.
Mom and Dad, after they caught on, eventually put a stop to it.
I never died. I can't vouch that I haven't been brain damaged by this, but I am still alive!
-------------------- Bender: Oh cruel fate, to be thusly boned. Ask not for whom the bone bones, it bones for thee. Posts: 1170 | From: Iowa | Registered: Aug 2004
| IP: Logged |
Ladies and gentlemen, let me introduce you to Ohm's Law. Current is the result of voltage divided by resistance. Now, about batteries...
Batteries are rated in terms of voltage and their energy output in mAh - milliamp hours (how many milliamps they can supply for how long). A 9-volt battery supplies 9 volts under its "rated" load - of 200mAh. That means a 9-volt can supply 200mA for an hour, or 100mA for 2 hours, etc. (In practice, as the battery weakens its voltage drops and it dies more quickly, but that isn't important here.) Put the 9V battery across a wet surface, like your tongue, and there will be sensation from the current that flows *between the terminals*. (Keep your eyes on this phrase, it will be important.) For a new battery, the current will be 9V divided by the contact resistance of the human tongue. How much this is, I don't know, but it's not really important. The energy rating (mAh) of the battery isn't important either because the duration isn't long enough to deplete the battery either.
Usually people get electrocuted and die because they have about 90mA or higher passing through their heart, which causes arrhythmia. Higher currents can stop the heart completely, which is in theory preferred, because you can be kept alive with CPR. (CPR cannot save a person from an irregularly beating heart.) People usually get electrocuted by grabbing a live wire and the current flow between their hands and across their heart, or from their hand to their feet. People can also be electrocuted when standing near a lightning strike, because the lightning will set up a high voltage between their feet (there's a long explanation about ground current flow and gradients here which I won't talk about.) In any case, flow of electricity needs two terminals - in and out.
If you put the battery on your tongue, current will flow between the terminals, and be restricted only to your tongue. You can't die from this - the current flow isn't anywhere near enough and it's local. A car battery would have similar results - the voltage is 12V and while it is much bigger, the current it supplies is limited by the resistance and not the size of the battery. Not that car batteries are harmless - putting a wrench across the terminals will weld it into place.
These numbers vary, but my rule of thumb is that voltages in excess of 25V DC and 50V AC are potentially unsafe. Typically people (like me) work on 24V DC systems live without any risk - you can't even feel the sensation of 24V DC on your fingers. Some electrical meters announce "unsafe voltage" at 30V or higher.
As for the web site, there are other ways to be killed while testing or using batteries besides sticking them on your tongue. Lead-acid car batteries give off hydrogen gas - a spark above a charging battery has had disastrous results. Battery chargers with high input voltages can also be dangerous.
-------------------- "The fate of *billions* depends on you! Hahahahaha....sorry." Lord Raiden - Mortal Kombat Posts: 1587 | From: Ontario, Canada | Registered: Apr 2005
| IP: Logged |
Well, that pretty much sums it up, I guess. I have, and still do, lick 9v batteries to see if they work. There is (IMO) no terrible shock; I wouldn't say it's pleasant, but it's by no means as bad as getting a 110v or 220v AC in you. 12v/500-mA transformer are about the limit for me, if I want to see if something stronger is live I'll break out the multimeter rather then lick it.
I'm sure a 9v battery could potentially be leveraged into killing someone, say by producing a high A/low V thing, hooking it to a set of EEG electrodes (the saline soaked thingiees they put on your scalp when they're checking brainwave activity), hooking it by similarly soaked electrodes to your heart area, etc. But taking even a 12v/1000mA shock to the tounge would probably not worry any normal electrician beyond a degree of discomfort.
Posts: 48 | From: Southern Kansas | Registered: Nov 2004
| IP: Logged |