I say :
NO, because the temperature is too low, it is a pure chemical process.
YES, because when salts are in the fire, its spectrum shows emission lines, e.g. the bright yellow Na-D line. When putting copper salts or even
metallic Cu in the fire, flames will be colored green-blue.
What do you think ?unionised - 24-1-2021 at 04:23
Since you can pass an electrical current through a flame, there's no way to dispute the fact that it's ionised, so it's a plasma.
On the other hand, it's a weak plasma- the degree of ionisation is low.
The yellow colour from sodium in a flame is due to neutral sodium atoms, rather than ions. Fantasma4500 - 28-1-2021 at 02:53
low density plasma, lets settle at that shall we. never really bothered to puzzle this one into place but i always knew fire and plasma was somehow
related unionised - 28-1-2021 at 04:49
There might be ionized atoms in a flame, but calling that plasma is like calling air for helium. rockyit98 - 28-1-2021 at 08:21
Nope! think of it as sea water. got some ions but mostly covalent molecules .and some free radicals here and there.clearly_not_atara - 28-1-2021 at 08:30
Instead of looking at specific questions like "is fire plasma?", physics as a discipline focuses on answers to questions like "how do I determine if a
sample is a plasma or a gas?". You will find a more orderly discussion here:
" A gas has zero conductivity, but when it turns into a plasma, its conductivity steadily grows but doesn't jump."
This is a little misleading: usually there is a point at which one of the derivatives of conductivity with respect to temperature, that is: (d/dT)^n
[S(T)] shows a singularity for some n. Also, sometimes plasmas do have a first-order phase transition, but it tends to be past the point at
which they start to ionized (the weakly-ionized to strongly-ionized first-order transition).
For a particular source you're interested in, the only way to know is to set it on fire and get a couple of electrodes and an ammeter
The best example plasma for teaching is probably a glow discharge, because a: it is relatively common and b: it emphasizes the key measurable property
of plasma (conductivity)
[Edited on 28-1-2021 by clearly_not_atara]metalresearcher - 28-1-2021 at 10:00
Glow discharge, is that not the same as a Corona discharge, appearing at high voltage power lines ?
In that case, the air close to the high voltage conductors, where the corona appears is also a plasma ?clearly_not_atara - 28-1-2021 at 10:09
Yes, that is definitely a plasma.macckone - 28-1-2021 at 16:38
It is partially ionized gas, aka plasma.
It isn't pure plasma, like in a sustained electric arc.
It is like asking if a slushy is a liquid or a solid.
Another example is fog or clouds, is it a liquid or a gas, in this case it is a suspension.
There should probably have its own name, I don't know ... like ... partially ionized gas.Morgan - 28-1-2021 at 16:51
Tidbit
"St. Elmo's fire is a weather phenomenon in which luminous plasma is created by a corona discharge from a sharp or pointed object in a strong electric
field in the atmosphere (such as those generated by thunderstorms or created by a volcanic eruption)." https://en.wikipedia.org/wiki/St._Elmo%27s_fire
