Talk:radioactive material

I've made the following changes to the definitions:

• I removed the part about unstable nuclei from the first definition. I'm only 90% sure that there are no other reasons for material to be radioactive, and in any case I think the technical definition is operational (it's radioactive if it emits particles) rather than theoretical (it's radioactive if it has an unstable nucleus undergoing thus-and-such kinds of nuclear reaction). But perhaps we should provide the theoretical defnition separately.
• I fixed the wikification of alpha particle etc. Linking to the definitions of alpha etc. didn't seem useful. I also decapitalized gamma ray. I left X ray capitalized, but that link seems to be broken.
• I generalized to "energetic particles", as I'm not convinced that the list given covers everything. E.g., a material might conceivably throw off something more exotic which then decays into something familiar.
• I added "signficantly above background levels" since by the original defnition everything is radioactive, but I believe that in practice the term is reserved for hotter-than-normal stuff. This is worth a bit more research, but I haven't done this (thus this note).
• I made the second definition "colloquial", realizing that this will make some folks uneasy, but ...
• I also shifted from "is" to "thought to be". I believe this definition correctly reflects usage while still pointing out that it's based on a common notion of the technical sense, not the sense itself.

I'm sure this will not be the last word -dmh 04:55, 7 September 2005 (UTC)

Correct, dmh. A few additional words follow here, for example:

1. radioactive substances emit particles from the atomic nuclei, not from the electron shells. Hence X-rays are not considered to be of radioactive origin - so I removed that one.
2. gamma rays are emitted as the nucleus have a surplus of energy. Although that means the nucleus is in an unstable state, I believe it to be a little misleading to claim the whole nucleus to be unstable (which to me sounds as it was going to fall apart)
3. I added instead protons, although not as common, there are isotopes which sends out such.
4. I am not sure about "above background levels" - why would you claim everything to satisfy the definition of 'radioactive' if we removed those words?

\Mike 09:08, 7 September 2005 (UTC)

To say that these ejected particles are "nuclear" are too ambigious, I think. Yes, they originate in the nucleus, but no, there were not necessarily any such particles there to begin with (i.e. the nucleus doesn't contain any of them). Gamma photons definitely not, for example. Neither any β⁺ (positrons). (Oh, behold! The wonders of quantum mechanics ;) \Mike 18:22, 7 September 2005 (UTC)

Looks like we were editing at the same time. OK, so "nuclear particles" is out. Drat. Maybe "as a result of a nuclear reaction" could go in somewhere?. In any case, thanks for the feedback, and here is what I meant by "everything is radioactive", modulo a bit of backpedaling:

I'm not completely comfortable with the current formulation, and what I said was not quite correct (unless proton decay pans out), but my point was this: First, most macroscopic matter will contain minute amounts of radiocative isotopes. The lead in a pencil will contain small amounts of ₁₄C, for example. If you put that pencil lead in a perfectly isolated environment and had very sensitive instruments, you would see low levels of radioactivity as that ₁₄C decays. Nonetheless, we don't consider ordinary pencil lead to be radioactive. Second — and this is what I originally had in mind but I'm no longer so sure of it — I'm pretty sure that any nucleus besides perhaps the lone proton of ₁H can decay spontaneously. The probabilities for a stable isotope are extremely low, but I'm pretty sure they're not zero. Twelve grams of ₁₂C contains Avogadro's number of nuclei, and if you roll the dice 6x10²³ times, it's no longer extremely unlikely that something will happen. In other words, even a lump of pure ₁₂C will exhibit some radioactivity, albeit very, very little. I think.

In any case, as a practical matter, most ordinary matter people will run across is, strictly speaking, ever so slightly radioactive, if only because it will contain trace amounts of radioisotopes. In practice, no one really cares about this. Most of the time, something is either clearly not radioactive enough to care about, or clearly is radioactive enough to care about. The only open question here is, is there a bright line between the two, or (more likely) is it a matter of context. -dmh 18:26, 7 September 2005 (UTC)

Lol, thanks. I think I got a bit carried away with the "nuclear" perspective, and forgot that the term being defined was "radioactive material".  :) \Mike 10:09, 12 September 2005 (UTC)

From RfD page

The following information has failed Wiktionary's deletion process.

It should not be re-entered without careful consideration.

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No more than the sum of its parts. SemperBlotto 07:27, 23 July 2005 (UTC)

Um, it seems to be a set phrase, outside of the nuclear power industry. Keep. --Connel MacKenzie 07:28, 23 July 2005 (UTC)

The definition is way off, a radioactive material should exhibit radioactivity. Whether it has been exposed to radiation or not is irrelevant. Is there anything in the universe that by the this definition does not constitute radioactive material? I would not even say it is the sum of its parts [25 July 2005]

There are different meanings to the term: the technical vs. the colloquial. You are correct in pointing out the common missconception and the technical inaccuracies of the colloquial meaning, but that doesn't make it less used. I would suspect that most people misuse the term in that manner. --Connel MacKenzie 13:59, 5 August 2005 (UTC)

I do not agree with the definition given, however, if this definition is deemed acceptable then this word is not the sum of its parts, as the object is not radioactive, and should therefore be kept. I however would advocate deletion.

I've done some tidying up, ready for deletion :-D

Removing {{rfd}}: we do not delete things because they are not idiomatic. Set-phrases are kept. This (even ignoring the idiomacy of the idiotic colloquial use) is certainly a common set-phrase. Also, thanks to the anon that did the cleanup. --Connel MacKenzie 17:09, 24 August 2005 (UTC)

• Delete. I don't think that set phrase, or idiomatic applies to this term. Radioactive material is simply nothing more than material which is radioactive irrespective of the reason for that radioactivity. As to the definition that is marked "erroneous", why bother to keep things that are wrong? Eclecticology 05:47:46, 2005-08-30 (UTC)

This is a dictionary, not the Repository of All Things Correct. We record usage, noting where one group uses a term in a sense that another considers incorrect (and to be clear here, I'm firmly in the scientific camp on this one). We record common misspellings so that people will know the widely accepted ones. We try to record the full spectrum of intended meanings for terms like conservative and liberal, even though the aggregate is blatantly contradictory. We record that some people seem to think that decimate has to mean "reduce by 10%" even though as far as anyone has been able to tell no one actually uses it that way.

We shouldn't throw out things that are "wrong" because, frankly, we're not that good at making the call. Most of the "This definition is wrong, the One True Definition is thus-and-such." complaints I've seen are superstitious rubbish passed down through a few generations of grammar guides written by self-appointed authorities and ultimately deriving from some patchy special pleading from the assumption that Latin is the gold from which base metals such as English descended through corruption. Decimate means destroy almost completely. You can stand at a podium as well as on it. Its is not the "genitive of it," at least not in the same sense that "des Mannes" is the genitive of "der Mann." The grammar modernes Englishes has no genitive per se, and the genitive of Old/Middle English hit was his.

One of the key features of Wiktionary is that anyone can "correct" it at any time, and so people do. Given that it takes two minutes to blindly insert an old wive's tale about usage and considerably longer to go and gather empirical evidence and present it, with a considerable probablility of having it "corrected" again, it's a minor miracle that we're doing as well as we are. -dmh 14:45, 7 September 2005 (UTC)

• Delete. Same reasons SemperBlotto and Eclecticology give here and I've given previously for Egyptian pyramid, touch-tone dialling, pulse dialling, and quite possibly others. — Hippietrail 20:08, 30 August 2005 (UTC)

• Delete. Not idiomatic. I don't think this phrase is used to refer to something that isn't giving off particles/rays. --Stranger 22:13, 30 August 2005 (UTC)

• Delete. For the same reasons Eclecticology gives. Ian Lewis 16:34, 1 September 2005 (UTC)

I cannot believe you people are suggesting this term is never missused, in exactly this way! Because it is missused more often than it is used technically correctly, it seems absurd to remove either definition: they both are marked clearly. (Well, they were the last time I looked.) Shall I begin pasting in 31,200 print citations?! http://print.google.com/print?q=radioactive+material&btnG=Search+Print --Connel MacKenzie 17:07, 1 September 2005 (UTC)

Connel, you're right, I'm not a physicist. I suppose when someone uses "radioactive" when they refer to a material that has been exposed to radiation, they really mean "irradiated?" But then, shouldn't that be an (erroneous) meaning of "radioactive"? Peace. --Stranger 17:42, 1 September 2005 (UTC)

Connel, if you find citations which do not mean "material which is radioactive" then paste them. Otherwise it is just as easy to find thousands of citations for "radioactive substance", "non-radioactive material", "material which is radioactive", "substance which is radioactive", and even such things as "red car" or "and the" - none of which are idiomatic and none of which belong in a dictionary. — Hippietrail 17:53, 1 September 2005 (UTC)

How about a listing from wordreference.com then? Not all combinations of words are noteworthy, but they (as do I) felt that radioactive material was notable...as well as radioactive dating, radioactive decay, radioactive dust, radioactive iodine excretion test, radioactive iodine test, radioactive iodine uptake test and radioactive waste. --Connel MacKenzie 21:37, 1 September 2005 (UTC)

Notability is too subjective a criterion to be applicable either way. It is a constant source of arguments on Wikipedia, and would be no less so if it were imported into Wiktionary. The idea that something that has been irradiated begins to emit radiation is probably as notable as any other urban myth, but that should not be enough to elevate that misconception to the level of a definition. At best, this false notion should be the subject of a usage note under radioactive. Eclecticology 22:54:30, 2005-09-04 (UTC)

I have placed the back rfd into the article, as it appears this matter is far from resolved TheSimpleFool 15:53, 5 September 2005 (UTC)

I am curently working as a radiation physicist, and to say the least, I was quite stunned to read the erronous definition. I would have never even thought of this definition being used, so for me this was quite an eye opener, it has merit in that I learnt something knew about radiation that I previously didn't. 143.117.143.42 08:20, 6 September 2005 (UTC)

In Brazil in the 1960s a radioactive Cobalt source was quite ludicrously disposed off by throwing it into a foundry. At that time it was undesireable to write off millions of reals(?) worth of steel, so they continued to use the steel from the foundry. This low grade steel used for pots, pans and bedframes emitted radiation, even though the cobalt only consituted a tiny fraction of the material. I would contend that the term radioactive material should encompass any material that has been contaminated with a radioactive substance in addition to one that consists entirely of an isotope with an unstable nucleus. 143.117.143.42 08:20, 6 September 2005 (UTC)

This is a classic case of differing technical and colloquial senses. From a purely physical point of view, the original definition given is rubbish, but (as Connel points out), both senses are correct lexicographically — people use both — and because of this divergence the term is clearly not idiomatic. I've ranted against labeling divergences like this "misnomers" (e.g., a koala bear is a perfectly good bear, just not in the strictly taxonomic sense), but something should be done in cases like the present. In a case like koala bear, I don't believe that many would argue that calling a non-ursid a "bear" is greatly harmful, but in the present case I'm sure a great many physicists and engineers will say that it's vitally important to know whether something is radioactive (and for that matter, to know the difference between radiation and radioactivity). We have a responsibility to note this in some way (and similarly with terms like chemical, natural and artificial). Probably a usage note would be the way to go.

As to the Brazilian cobalt, the steel was clearly radioactive in the colloquial sense. For the technical sense the test is whether the material is throwing off siginficant numbers of particles itself, not whether it has ever been exposed to or admixed with something radioactive. Depending on how much cobalt found its way into the mix, the steel might or might not have been radioactive to a significant degree (I'm guessing that since the story is still told to this day, it might well have been). I say "significantly radioactive" since any macroscopic amount of matter at a temperature above absolute zero is at least somewhat radioactive. The steel in question may have been no more radioactive than Brazil nuts (which register noticeably above background levels), or may not have been noticeably radioactive at all.

At some point, we veer from lexicography into (other) aspects of cognitive science — e.g., the relations among our instinctive notion of contamination, the modern medical concept, and radiation as an agent of disease — but that's for another, longer treatise.

On an aside, is there a catgory for "wrong" definitions, I've found this whole thread fascinating, and I'm sure that radioactive material isn't the sole example of something with such a ludicrous alternative definition (sorry if i've posted this to the wrong place, but I'm quite new to this). TheSimpleFool 08:43, 7 September 2005 (UTC)

Heh. Any suggestions what to call it? (No, wait! Don't go there! There's a monster behind that door!) -dmh 14:51, 7 September 2005 (UTC)

• Deleted. The real issue was not the definition of "radioactive" but whether "radioactive material" was anything more than material that was radioactive. Eclecticology 05:19, 17 September 2005 (UTC)