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Author Topic: Jagged Lightning ?....why ?  (Read 5417 times)

Offline neilep

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Jagged Lightning ?....why ?
« on: 27/01/2005 20:54:41 »
Hello Peeps of Wondrous Scientific Orientated lovliness,

I just caught a glimpse of a ligtning storm on TV and it reminded me of a question I want to ask...and that is:

If lightning always seeks the shortest route to earth, then why does it go down tangent avenue and become all jaggedy etc...surely this is inefficient and a pure straight line would be quicker eh ?

Strike  me with a bolt of intelligence  and increase my IQ to two :D

Thanks

Neil

'Men are the same as women...just inside out !'
« Last Edit: 27/01/2005 20:55:19 by neilep »


 

Offline DrPhil

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Re: Jagged Lightning ?....why ?
« Reply #1 on: 27/01/2005 23:12:58 »
Lightning takes the path of least resistance through the air. The path of least resistance is almost never the shortest route or a straight line.
 

Offline gsmollin

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Re: Jagged Lightning ?....why ?
« Reply #2 on: 28/01/2005 16:31:04 »
That's a simplification, but still essentially true. There are powerful electric fields between the cloud and the ground. The air is non-conducting. At some point, in localized areas, the electric field gradient will exceed the ionization potential of the air, and ionized air forms. This sometimes produces a discharge of its own, known as corona, ball lightning, or St. Elmo's fire. If you ever see a corona discharge around some item on the ground, or a tree limb, or whatever, do not approach it! A true lightning strike is imminent. The ionized air can conduct electricity, and a column of ionized air will begin to form, moving back up to the cloud. Now remember there can be many of these ionized areas forming simultaneously. When the ionization reaches all the way to the cloud, a main strike can form. The main strike can be thousands of amperes, and causes secondary strikes by by electric, and magnetic induction. I was once struck by a secondary strike 1/4 mile from the main strike. Many of these strikes will occur in those areas that were partially ionized, so the strike may branch because of that.
 

Offline neilep

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Re: Jagged Lightning ?....why ?
« Reply #3 on: 28/01/2005 20:07:12 »
Thank you Dr Phil and thank you gsmollin for your consice answer. I would love to see ball lightning....so it's not a myth then.....thanks again...my IQ just jumped a notch. Cripes !!..you were struck, diod it knock you out ?...any side effects like glowing teeth and extremities  ?   ;-)

'Men are the same as women...just inside out !'
 

Offline gsmollin

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Re: Jagged Lightning ?....why ?
« Reply #4 on: 28/01/2005 21:16:11 »
Geez you're fast. I was going to edit my post, but too late. Anyway, here is a link that discusses lightning leaders and streamers, and the jagged paths they take:
http://science.howstuffworks.com/lightning4.htm

OBTW, I was going to edit my use of the term "electric field gradient" to "electric field intensity". That's the correct term. As the "ionization gradient" increases in the streamers, it can reach the critical level where the main strike occurs. Not all streamers cause lightning strikes, which is why people can tell stories about ball lightning without having suffered a lightning strike. In some places, like mountains with steep slopes, it is very common to see.

My own minor strike was uncomfortable, but not dangerous. All I can say is that in an electric storm do not touch ungrounded metal, since that is an antenna for lightning. I was leaning on my aluminum window frame when I got nailed. I wonder why electrical codes don't require such large pieces of metal to be grounded.
 

The Naked Scientists Forum

Re: Jagged Lightning ?....why ?
« Reply #4 on: 28/01/2005 21:16:11 »

 

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