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Re: Sparks and temperature

Subject:  Re: Sparks and temperature
  Date:  Fri, 9 May 1997 01:47:59 +0500
  From:  "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
    To:  Tesla List <tesla-at-pupman-dot-com>


On Tue, 6 May 1997 19:38:42 +0100 V C Watts
<V.C.Watts-at-btinternet-dot-com> wrote;

> Please excuse any protocol anomalies as this is my first response to any
> group and I only joined the list a few days ago.

I would have never known if you hadn't told us! Your doing great for 
a Newbie!

>> On Mon, 5 May 1995 12:49:00 +0500
>> <alfred.skrocki-at-cybernetworking-dot-com> wrote
>> If you take a neon sign transformer and connect it to an 
>> adjustable gap and set it just to where a spark can't jump then 
>> hold a match several inches under the gap a spark will immediately 
>> jump the gap and continue to arc until the match is removed, then 
>>it will stop.
 
> The suggestion was that the heat cause the gap to spark.  Is it not
> possible the cloud of electrons around the flame would be ionizing the
> air and helping the conductive path.

VERY ASTUTE OBSERVATION! I am surprised that none of my more 
experienced colleagues didn't postulate that! I thought that too
initially and I have tried it with air piped to the gap from a hot air 
gun, I also tried sending the air from the hot air gun through a 
small air deionizer and then to the gap and in all cases the results 
were the same. My conclusion is that heat decreases the breakdown 
voltage of air. Actually this is why a Jacobs ladder works, the high
voltage initially can just jump the small gap at the bottom, but the 
heat created by the arc lowers the breakdown voltage of the air above 
it so the spark can rise up between the angled electrodes (being 
encouraged to do so by the convection due to the rising hot air) 
until it reaches the top when the rising air causes the arc to break
with a resounding snap only to start all over again at the bottom 
gap. Sure in the case of the Jacobs ladder the metal ions assist
matters as well.

                               Sincerely

                                \\\|///
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                           Alfred A. Skrocki
                   alfred.skrocki-at-cybernetworking-dot-com
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