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On 6 Jun, 06:45, D Peter Maus wrote:
Brian Oakley wrote: "RHF" wrote in message roups.com... On Jun 4, 3:20 am, "download.com" wrote: "RHF" wrote in message . . Ever wonder why they use Fiberglass Poles in a Tent ? I didn't know that. I learned something!!!!! Burr Burr - Sort of like the story of the Golfer who raised his Cub and said : Looks like We could be getting some Thunder & Lightning . . . zzzzzzzzzzz ZAP ! ~ RHF Filerglass Tent Poles are lightweight and breakdown to a small Packable Size and that is good -but- they also do not function as a Lightning Attractor like a Metal Pole would. The "Plastic" Tent Poles in creap Tents will often start to wrap in high heat areas. Know a few people who will only use the "Non Metalic" Tent Stakes up in the High Sierras as an extra step to protect themselves from T&L -but- they leave their metal Pack Frames in the Tent ? ? ? ;-) . . Now we are getting a little ridiculous. if lightening will jump thousands of feet, what in the world would make you think that a little bit if metal such as a tent pole would attract it away from where it was headed in the first place? Youre talking about hundreds of thousands of volts, if not more. You think that fiberglass wouldnt conduct electricity at that kind of voltage and current? Please ![]() B The issue is not whether the fiberglass pole would conduct better or worse than the metal pole, but rather, the issue is where the discharge originates. There are multiple phases of a lightening strike. Two significant phases, the visible ones, are the leader stroke and the return stroke. The leader stroke is from cloud to sky. It's often not visible, or obscured by the return blast. The leader stroke will strike an object, and often, but not always, create an ionized path that will facilitate the return stroke. It's the return stroke that contains the Wrath of God energy. And the return stroke originates at the surface and moves from ground to sky. The leader stroke, like all electrical phenomena, seek the path of least resistance to ground. Height and conductivity will matter most, here. If there is a high object of relative conductivity, the leader stroke will move there. Living tissue, owing to the solutes within it's fluids, will have a greater conductivity, and/or break down resistive materials under heavy voltage more readily than a fiberglass pole. So, the use of fiberglass is often, but not always, an effective measure of safety where electrical storms are an issue, because an ionized path can be created more readily elsewhere with much lower electric field strength. A metal pole, however, presents a number of electrical advantages to both the leader stroke and the return blast. Among them, besides the obvious enhanced conductivity while in contact with the ground, is the high curvature at the top end of the pole. High curvature on a conductor concentrates the electric field flux offering a dramatically much easier release of current than a flat object. This is why users of a Van De Graaf generator note a corona discharge around the heads of tacks, points of pins, and the like. A metal pole, stuck in the ground offers an enormous level of electric activity that should a potential develop, a discharge would happen at a much lower potential. Making both leader stroke and a return blast more likely than with a fiberglass pole should conditions develop. It also means that many such strokes may be dissipated before they can become dangerous by releasing electrons through corona discharge at points of high curvature. This is how lightning rods work. But in the case of metal tent poles, the ground system is random, not engineered for efficiency, and poles of even height are often too few in number to offer sufficient corona release to forestall a stroke. So, a metal pole becomes more dangerous than a fiberglass pole when conditions are right for lightning to occur. There was a BBC Horizon programme all about lightning in which they had by a sheer fluke of filming managed to shed new light on why nearby objects get zapped too. The leader strike almost invisibly 'meanders' down from the cloud to the ground but stops just short. Then a forest of lightning strokes rise from the ground to meet it, emanating from any good surface like a bloke with a golf club etc. Amazingly they managed to get this on film, only one frame before the main discharge, and it was like white cobras leaping from the ground. Once one of these touches the leader stroke the cloud is earthed and everything happens but apparently all the electrical damage to nearby objects has already been done by these preliminary strokes. Amazing stuff to actually see! D. |
#2
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On Jun 6, 11:50 pm, Duncan wrote:
On 6 Jun, 06:45, D Peter Maus wrote: Brian Oakley wrote: "RHF" wrote in message roups.com... On Jun 4, 3:20 am, "download.com" wrote: "RHF" wrote in message . . Ever wonder why they use Fiberglass Poles in a Tent ? I didn't know that. I learned something!!!!! Burr Burr - Sort of like the story of the Golfer who raised his Cub and said : Looks like We could be getting some Thunder & Lightning . . . zzzzzzzzzzz ZAP ! ~ RHF Filerglass Tent Poles are lightweight and breakdown to a small Packable Size and that is good -but- they also do not function as a Lightning Attractor like a Metal Pole would. The "Plastic" Tent Poles in creap Tents will often start to wrap in high heat areas. Know a few people who will only use the "Non Metalic" Tent Stakes up in the High Sierras as an extra step to protect themselves from T&L -but- they leave their metal Pack Frames in the Tent ? ? ? ;-) . . Now we are getting a little ridiculous. if lightening will jump thousands of feet, what in the world would make you think that a little bit if metal such as a tent pole would attract it away from where it was headed in the first place? Youre talking about hundreds of thousands of volts, if not more. You think that fiberglass wouldnt conduct electricity at that kind of voltage and current? Please ![]() B The issue is not whether the fiberglass pole would conduct better or worse than the metal pole, but rather, the issue is where the discharge originates. There are multiple phases of a lightening strike. Two significant phases, the visible ones, are the leader stroke and the return stroke. The leader stroke is from cloud to sky. It's often not visible, or obscured by the return blast. The leader stroke will strike an object, and often, but not always, create an ionized path that will facilitate the return stroke. It's the return stroke that contains the Wrath of God energy. And the return stroke originates at the surface and moves from ground to sky. The leader stroke, like all electrical phenomena, seek the path of least resistance to ground. Height and conductivity will matter most, here. If there is a high object of relative conductivity, the leader stroke will move there. Living tissue, owing to the solutes within it's fluids, will have a greater conductivity, and/or break down resistive materials under heavy voltage more readily than a fiberglass pole. So, the use of fiberglass is often, but not always, an effective measure of safety where electrical storms are an issue, because an ionized path can be created more readily elsewhere with much lower electric field strength. A metal pole, however, presents a number of electrical advantages to both the leader stroke and the return blast. Among them, besides the obvious enhanced conductivity while in contact with the ground, is the high curvature at the top end of the pole. High curvature on a conductor concentrates the electric field flux offering a dramatically much easier release of current than a flat object. This is why users of a Van De Graaf generator note a corona discharge around the heads of tacks, points of pins, and the like. A metal pole, stuck in the ground offers an enormous level of electric activity that should a potential develop, a discharge would happen at a much lower potential. Making both leader stroke and a return blast more likely than with a fiberglass pole should conditions develop. It also means that many such strokes may be dissipated before they can become dangerous by releasing electrons through corona discharge at points of high curvature. This is how lightning rods work. But in the case of metal tent poles, the ground system is random, not engineered for efficiency, and poles of even height are often too few in number to offer sufficient corona release to forestall a stroke. So, a metal pole becomes more dangerous than a fiberglass pole when conditions are right for lightning to occur. There was a BBC Horizon programme all about lightning in which they had by a sheer fluke of filming managed to shed new light on why nearby objects get zapped too. The leader strike almost invisibly 'meanders' down from the cloud to the ground but stops just short. Then a forest of lightning strokes rise from the ground to meet it, emanating from any good surface like a bloke with a golf club etc. Amazingly they managed to get this on film, only one frame before the main discharge, and it was like white cobras leaping from the ground. Once one of these touches the leader stroke the cloud is earthed and everything happens but apparently all the electrical damage to nearby objects has already been done by these preliminary strokes. Amazing stuff to actually see! D.- Hide quoted text - - Show quoted text - Duncan - Makes you 'wonder' what happen to . . . the Camera that took the Picture z...Zap ! ~ RHF |
#3
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Probally about the same thing that happens to those cameras filming the
Space Shuttles big tank when they are going up.And that camera in the Bruce Willis movie, Armageddon.Bye Bye camera. About three or four something years ago, I saw an interesting article on the internet about Ice Lightning, or maybe it was Lightning Ice.Something about (I think) Ice crystals have something to do with Lightning.It might have been at www.livescience.com where I read that article. cuhulin |
#4
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