Re: visibility of an arc

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Thomas Coyle" <zxcasd@xxxxxxxxx>

I'm not sure I agree with this - I have trouble believing that the 
sparks we're seeing are getting the air up to 10,000K, which is what 
would be required to get the characteristic blue color if it's just 
blackbody radiation.

Of course, there's a "simple" way to test it - just enclose a coil in 
plexi, evacuate it, and replace it with neon (for example). Of 
course, that sounds an awful lot like a plasma globe, which colors 
definitely aren't caused by blackbody radiation.


On 4/10/06, Tesla list <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx> wrote:
Original poster: Jim Lux <<mailto:jimlux@xxxxxxxxxxxxx>jimlux@xxxxxxxxxxxxx>

At 08:04 AM 4/10/2006, Tesla list wrote:
>Original poster: BunnyKiller <<mailto:bunikllr@xxxxxxx>bunikllr@xxxxxxx>
>
>Hi Langer...
>
>we see it pretty much the same way we see a neon tube glowing...


Folks.. all this talk of ionization levels and such are fine, and
there's no doubt that some of the light coming of the sparks on a TC
is from excited nitrogen.  Nitrogen has a whole raft of lines all the
way from red to blue.

However, the dominant source of light is going to be blackbody
radiation from hot gas, at least for any spark that's reasonably bright.