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ocheewah
Skeptic Friend
USA
50 Posts |
 Posted - 09/16/2005 : 07:52:29
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http://www.abc.net.au/news/newsitems/200509/s1461751.htm
You hear about this kind of thing periodically. Someone want to take a shot at explaining it to me? If he was melting plastic and leaving scorch marks behind him, why wasn't he burned as well?
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Those who danced were thought quite insane by those who could not hear the music. |
Edited by - ocheewah on 09/16/2005 07:54:13
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Valiant Dancer
Forum Goalie
USA
4826 Posts |
Posted - 09/16/2005 : 07:58:17 [Permalink]
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quote:
Originally posted by ocheewah
http://www.abc.net.au/news/newsitems/200509/s1461751.htm
You hear about this kind of thing periodically. Someone want to take a shot at explaining it to me? If he was melting plastic and leaving scorch marks behind him, why wasn't he burned as well?
Because he had the same charge as his clothes. There was no difference in charge between him and his clothes so there was no movement of static electricity from him to his clothes. |
Cthulhu/Asmodeus when you're tired of voting for the lesser of two evils
Brother Cutlass of Reasoned Discussion |
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markie
Skeptic Friend
Canada
356 Posts |
Posted - 09/16/2005 : 08:28:23 [Permalink]
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quote:
Originally posted by ocheewah
http://www.abc.net.au/news/newsitems/200509/s1461751.htm
You hear about this kind of thing periodically. Someone want to take a shot at explaining it to me? If he was melting plastic and leaving scorch marks behind him, why wasn't he burned as well?
quote:
Victorian authorities believe a man built up at least 30,000 volts of static electricity in his jacket simply by walking around the western Victorian city of Warrnambool yesterday...."This poor guy has built up static electricity thanks to an unfortunate combination of insulating clothes that he's wearing, static, synthetic clothes, just walking along and he's just building up this static charge everywhere," Dr Kruszelnicki said.
Fact. One doesn't just invent such things. Hey, with some modifications perhaps a novelle type of electric power generating device could be in the works :)
(I heard very recently that a device has been developed which is worn on one's back, and which produces and stores electricity produced by walking motion, sufficient to power several electrical devices like cellphones, mp3 players and such.)
Mark
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ocheewah
Skeptic Friend
USA
50 Posts |
Posted - 09/16/2005 : 08:43:17 [Permalink]
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| Suppose that makes sense. I really am a fairly intelligent creature but my brain does not always grasp basic scientific principles unless they are put in ten words or less. That whole left brain/right brain thing. |
Those who danced were thought quite insane by those who could not hear the music. |
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H. Humbert
SFN Die Hard
USA
4574 Posts |
Posted - 09/16/2005 : 09:46:37 [Permalink]
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quote:
Originally posted by Valiant Dancer
Because he had the same charge as his clothes. There was no difference in charge between him and his clothes so there was no movement of static electricity from him to his clothes.
Yeah, but 30,000 volts!? Wouldn't the guy fry himself the second he grabbed a metal door handle?
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"A man is his own easiest dupe, for what he wishes to be true he generally believes to be true." --Demosthenes
"The first principle is that you must not fool yourself - and you are the easiest person to fool." --Richard P. Feynman
"Face facts with dignity." --found inside a fortune cookie |
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Valiant Dancer
Forum Goalie
USA
4826 Posts |
Posted - 09/16/2005 : 10:03:40 [Permalink]
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quote:
Originally posted by H. Humbert
quote:
Originally posted by Valiant Dancer
Because he had the same charge as his clothes. There was no difference in charge between him and his clothes so there was no movement of static electricity from him to his clothes.
Yeah, but 30,000 volts!? Wouldn't the guy fry himself the second he grabbed a metal door handle?
Depends on the amperage. He seemed to be insulated enough where he didn't discharge across his heart or crispy himself. Seemed to be zapping from his clothes to his environment.
The voltage doesn't kill you, the amperage does. |
Cthulhu/Asmodeus when you're tired of voting for the lesser of two evils
Brother Cutlass of Reasoned Discussion |
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Dr. Mabuse
Septic Fiend
Sweden
9688 Posts |
Posted - 09/16/2005 : 15:43:40 [Permalink]
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If the clothes he was wearing was conductive, he would primarily be inside a Faraday's Cage, in which case he will be protected. And if the clothes he was wearing had lower resistance than his skin, that's where the current would flow.
An electrical spark is about 2000 volts per cm, which means that he was building up for a 15cm (close to 6") spark.
30'000 volts is usually found in the ignition systems of cars, however, the spark-plug has a much smaller gap.
It does seem unlikely, but not impossible. |
Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
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"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
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Send them unarmed civilians for target practice..
Collateralmurder. |
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tw101356
Skeptic Friend
USA
333 Posts |
Posted - 09/16/2005 : 19:51:02 [Permalink]
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At boarding school, my friends and I would hold hands and scuff our leather-soled shoes on the wool carpet to build up a charge. Then one of the end people would touch a victim on the ear. Cheap thrill, I know.
When we touched a radiator we could get a spark to jump a gap of almost an inch. One person said that a one inch spark indicated about 20 kilovolts. Lo and behold, my ancient CRC Handbook of Chemistry and Physics has a table showing spark length between sperical electrodes which backs this up.
Scuffing feet doesn't generate much current, but the voltage is pretty impressive.
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- TW
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ktesibios
SFN Regular
USA
505 Posts |
Posted - 09/16/2005 : 20:04:44 [Permalink]
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I have my doubts about this. Human body models used in ESD susceptibility testing use a body-to-surroundings capacitance of 100 to 250 pF. A 250 pF capacitor charged to 30 kV stores 112.5 mJ of energy. That's roughly equal to 0.0106% of the energy released by a kitchen match head (said to be about 1 BTU by the US DOE's Energy Information Administration). That's plenty to destroy the gate insulation of MOSFETs or even damage PN junctions, but I find it hard to believe that it would be enough to melt plastic objects or scorch carpets.
Here is a neat little paper about experimental validation of industry standard ESD test "signals". The experimenters actually charged real human test subjects up to nice high voltages and had them zap it to targets while capturing voltage and current waveforms.
Ouch. 
While the peak currents can be several amperes, the current flows mainly through the skin and the pulse duration is only in the hundreds of nanoseconds maximum, so it's no surprise that static electric shocks don't fry you. |
"The Republican agenda is to turn the United States into a third-world shithole." -P.Z.Myers |
| Edited by - ktesibios on 09/16/2005 20:07:04 |
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BigPapaSmurf
SFN Die Hard
3192 Posts |
Posted - 09/19/2005 : 05:36:39 [Permalink]
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He must have been discharging all over the place, strange indeed. I know! God did it.
How bout a 500 kilovolt shock?
http://hypertextbook.com/eworld/vdg.shtml
quote:
Sparks
When the grounded discharge wand is brought near the collector dome, lightning discharges will occur, accompanied by a crackling sound. Try varying the distance between the wand and the collector to see the different types of sparks the generator can produce. Some are white-hot and quite intense, others are a red-purple and less intense. Try to see how long you can get the white-hot sparks to jump. Under the best circumstances, sparks can leap up to fifteen inches. I believe the rule is three inches for every 100,000 volts.
Current Kills, not Voltage
If you feel adventurous you can try discharging the generator without the wand. Bring the side of your forearm near the collector. Do not allow the generator to run long before doing this. If you come up on it pretty fast it won't have time to accumulate a lot of charge and you can zap yourself with relatively little pain. You could also try holding a fluorescent tube. The length of the tube offers some protection from really violent shocks and the tube will light up. The voltage is still high enough to hurt slightly but the current is so low it really can't harm you
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"...things I have neither seen nor experienced nor heard tell of from anybody else; things, what is more, that do not in fact exist and could not ever exist at all. So my readers must not believe a word I say." -Lucian on his book True History
"...They accept such things on faith alone, without any evidence. So if a fraudulent and cunning person who knows how to take advantage of a situation comes among them, he can make himself rich in a short time." -Lucian critical of early Christians c.166 AD From his book, De Morte Peregrini |
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filthy
SFN Die Hard
USA
14408 Posts |
Posted - 09/19/2005 : 06:04:38 [Permalink]
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I've been wondering about this since reading of it yesterday. It hardly seems posssible that a human could transfer that much voltage, even at low amp, setting stuff on fire(!), and still stand up without shaking. I once got nailed by the coil on my race bike (80,000v) and was twitchey for the rest of the day.
Thanks for all the info.
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"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
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and Crypto-Communist! 
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beskeptigal
SFN Die Hard
USA
3834 Posts |
Posted - 09/20/2005 : 01:32:05 [Permalink]
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Not being the expert, I can't make a definitive guess but I do have to maintain a bit of skepticism here.
I once put a nice foam pad in the back of a little pick up truck I owned at the time. I ended up having to hold onto the wheel well to stay grounded since my every movement created a charge. I can't see it building up much higher than that experience and no fires were sparked. |
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