About how to prevent being struck by lightning

[moo]

Thanks for the link Alex4eva.

The link I had for the homemade detector mentioned earlier is dead, but here's an image I had saved. The ferrite rode is inside a PVC pipe with end caps.

moo

 

[tehno]

Lightning, about 100,000,000 volts of it, travels through air, a pretty good insulator, often more than a mile to the ground. How can 6" of tire compare?

It's nonsensense to say that lightning is about 100 000 000 V.
Even aproximately.
Nobody has ever measured lightning potential (I think it's impossible ).
Only you can do is to measure currents and the induced potentials in struck objects.

 

[Loren Booda]

tehno,

Just Google "lightning volts" and you may have your answer.

"Sometimes I've believed as many as six impossible things before breakfast."

 

[tehno]

tehno,

Just Google "lightning volts" and you may have your answer.

"Sometimes I've believed as many as six impossible things before breakfast."

"The Google answer" vary between 10,000,000 V and 1000,000,000 V.
3 order of magnitudes..And that's just an aproximation

 

[SF]

Well, I'd reckon since not all clouds are the same, the lightnings must also be different :)

 

[indoforce]

So if standing with feet together is safer, would it be safest to stand on the toes of one foot?

 

[PhanthomJay]

Crouch and place your heels together..AND...block your ears with your hands. The sound of lightning that close can blow your eardrums out. BTW, if the rare event that an electrical power line ever fell on your car with you inside it, STAY IN THE CAR. Numerous deaths have resulted when the driver panics and exits the auto, making contact with the vehicle and ground, and its curtains. Inside, you're much more protected as in a Faraday cage. I wouldn't touch any metal though, hands off the keys. Wait for professional help to arrive.

 

[PhanthomJay]

So if standing with feet together is safer, would it be safest to stand on the toes of one foot?

Hah, if you can crouch on one toe and block your ears, you're much more athletically inclined than I. The heel to heel approach may burn your feet, but it's better than taking 100,000 amps thru the heart for sure.

 

[moose]

Inside, you're much more protected as in a Faraday cage. I wouldn't touch any metal though, hands off the keys. Wait for professional help to arrive.

Yeah, it's not really a perfect Faraday cage as some people imagine it to be.

 

[Loren Booda]

Two of us watched in horror as a friend standing on a train had 5,000 volts arc to the left side of his neck (and blow off the bottom of his left shoe). Had the electricity arced to the right side of his neck, we were told, his heart would have been fried. The spark also ignited the vapors of the tank car in which he had been peering, giving him 50% burns. One other strange thing: the potential in his body was great enough to blow his metal frame glasses off of his head. He recovered more or less fully.

 

[HalfManHalfAmazing]

I saw criss angel get shot by lightening.

 

[tehno]

Two of us watched in horror as a friend standing on a train had 5,000 volts arc to the left side of his neck (and blow off the bottom of his left shoe). Had the electricity arced to the right side of his neck, we were told, his heart would have been fried. The spark also ignited the vapors of the tank car in which he had been peering, giving him 50% burns. One other strange thing: the potential in his body was great enough to blow his metal frame glasses off of his head. He recovered more or less fully.

He tried to commit suicide,or he didn't know the train powerline was energized?He was lucky he didn't buy the farm ..
BTW,his glases were not blew off of his head due to potential ,but probably by a powerful electric arc action .
The arc phenomenon occurs in explosive fashion (the same reason why you can hear thunder caused by lightning) :beside expansion of air and almost "instantenous" melting of materials in contact zone of the arc currents can peak kiloampere range causing strong local magnetic forces of repulsion.
I think an electric chair in states used voltage of aproximately 5000 V for executions .Your friend was very lucky.
Speaking of lightning and that you are completely safe in car or hause you may want to read this report: http://www.news.com.au/story/0,23599,20548077-13762,00.html

(And please don't laugh at it)

 

[Loren Booda]

And people laugh at safe sex.

 

[wxrocks]

Of course lightning has potential

It's actually easy to approximate the voltage of lightning -- What you really have is a capacitor with air as the dielectric. According to wikipedia, the dielectric strength of air is about 3 MV/m -- so using that knowledge and a few intro physics equations it is pretty easy to at least estimate the potential in lightning.

 

[tehno]

Firstly,at 2500 m altitude ,the dielectric strenght of air is ~ 2 MV/m.
But I disagree with you on basis of another (measured )fact.
Just a second or so prior to the lightning,a typical measured field on terrestial level is typically 10 kV/m = 0.01 MV/m.
With assumption of uniform field distribution, the voltage taken along path 2000-3000 m turns out to be :20 - 30 MV.
Taking your value of 3 MV/m in the account this voltage can be as high as:
9000 MV.
Man that's 9 Gigavolts !
Easy eastimate?I don't think so!

 

[jdlawlis]

potential difference during lightning strikes

Richard Feynman has a good discussion of thunderstorms in his three volume Lectures on Physics (see Volume 2, Chapter 9). He estimates that the charge on the bottom of a cloud during a thunderstorm is large enough to produce a potential difference of 20, 30 or even 100 million volts between the cloud and Earth. This results in an electric field strength on the order of 1E5 V/m, which is an order of magnitude lower than the dielectric breakdown of dry air at atmospheric pressure. The dielectric breakdown of air at the base of a thundercloud is much less than 3E6 V/m, however, due to reduced air pressure (Paschen effect) and the presence of water droplets (Macky effect).