Talk:Plasma (physics)

Flames

Unfortunately I can't edit this page myself. Too bad, but I hope someone will read this and do the correction.

In the "common forms of plasma" we have "Some extremely hot flames [citation needed]".

First of all - the citation can be found in the "flames" article:

Secondly, that citation doesn't claim that only "extremely hot flames" are plasma, but rather that ALL flames are plasma, including the flame of a candle: "What about fire? The flame of a burning candle is ionized, as we now know, and thus a plasma". So the article should be corrected by replacing "Some extremely hot flames" with "The flames of a fire (even candles)". 85.250.65.114 (talk) 10:38, 27 May 2012 (UTC)

I agree that this should be fixed. There's a nice YouTube video called "Electric Flame" (linking to youtube is so complicated). It demonstrates that flames contain ions. Tadmuck (talk) 19:10, 2 March 2013 (UTC)

State of matter

I didn't see any citation for plasma being a forth state of matter. I came here looking for evidence of it but all I could find was a table that seems to be trying to show that it is a 4th state but it's not very convincing. Specific question I am left with: If gases become plasmas when they are ionized, why do liquids not have a separate state of matter when they are ionized? Calling plasma a separate state of matter seems premature since they are apparently still being heavily researched and it also seems like something self-important physicists would claim, hence why I am looking for the actual citations.

Also, why is this article restricted to (physics)? shouldn't it also have a (chemistry) entry or preferably none of these parentheses at all? esp. given its status as 4th state of matter it would be of interest to students of chemistry69.223.177.179 (talk) 23:24, 16 January 2012 (UTC)

"State of matter" is not such a well-defined concept that everyone agrees on what is or isn't a separate state, and consequently it isn't of central importance to the physical sciences. There is a disambiguation article on Plasma, without parentheses, but chemists will be interested in the same definition of plasma as physicists. Art Carlson (talk) 07:51, 17 January 2012 (UTC)

It's really considered to be "common knowledge" that plasma is considered to be a fourth state of matter.  ;) — Preceding unsigned comment added by 68.196.248.241 (talk) 01:11, 16 June 2012 (UTC)

Removed ball lightning

I have removed ball lightning because the page linked doesn't even say what it is, so we can't say it is plasma.

From the page:

Ball lightning is an unexplained atmospheric electrical phenomenon. The term refers to reports of luminous, usually spherical objects which vary from pea-sized to several metres in diameter. It is usually associated with thunderstorms, but lasts considerably longer than the split-second flash of a lightning bolt. Many of the early reports say that the ball eventually explodes, sometimes with fatal consequences, leaving behind the odour of sulfur.

[23 May 2006]

Iæfai (talk) 02:52, 19 March 2012 (UTC)

Definition in Introduction

Not to nitpick but since this is a physics-related topic and a certain amount of "rigor" might be expected, I wonder if it might be more appropriate to say that plasma is a *kind* of matter, or *form* of matter; rather than a "state of matter." After all, plasma is an actual "physical substance" with mass, electrical charge, etc., it's not just a state, it's the actual matter itself. "State of matter" implies that Plasma = state - - but Plasma *is* matter. I only mention it since, like I said, it's a physics-related article and a certain amount of "rigor" might be appropriate.

I think "state of matter" is more appropriate, similar to its use when describing solids, liquids and gases. They could also be argued to be "kinds" or "types" of matter, but we are describing the state of matter here. --Iantresman (talk) 22:34, 8 November 2012 (UTC)

Comparison to the gas phase

In the section "Comparison of plasma and gas phases", the text reads that plasma ".. is closely related to the gas phase in that it also has no definite form or volume".

One of the characteristics of plasmas, is that it may indeed have both definite form and volume, eg. filamentation, the stars, heliospheric current sheet, etc. Should we reword, or find a different similarity? --Iantresman (talk) 22:59, 8 November 2012 (UTC)

What about the CRT

Does a cathode ray tube, or for that matter, any vacuum tube have a plasma? I like to saw logs! (talk) 06:17, 30 January 2013 (UTC)

'...Even black holes' (disapprove of this description)

Even black holes, which are not directly visible, are fuelled by accreting ionising matter. This is a weird assertion; that black holes are 'fuelled'. I cannot find any support for that idea in the reference either. 70.185.104.164 (talk) 06:39, 21 April 2013 (UTC) BGriffin