Talk:Helium

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Helium is a featured article, which means it has been identified as one of the best articles produced by the Wikipedia community. If you see a way this page can be updated or improved without compromising previous work, feel free to contribute.

Article changed over to new WikiProject Elements format by maveric149

Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory - Helium (http://periodic.lanl.gov/elements/2.html). Additional text was taken directly from, from the Elements database 20001107 (via dict.org (http://www.dict.org)), Webster's Revised Unabridged Dictionary (1913) (via dict.org (http://www.dict.org)) and WordNet (r) 1.7 (via dict.org (http://www.dict.org)). Data for the table was obtained from the sources listed on the main page and WikiProject Elements but was reformatted and converted into SI units.

Talk

The "magic number" reference needs to be described in the magic number disambiguation article as the existing entries do not apply to this context. RedWolf 03:52, Dec 31, 2003 (UTC)

The second paragraph under "Forms" begins, "As it is cooled past 2.1768 K at its vapor pressure..." But the table of data says "not applicable" under vapor pressure. Huh? And why wouldn't the vapor pressure be applicable to helium if it can exist as a liquid? Eric119 23:42, Mar 14, 2004 (UTC)

What about the effects of helium on the human voice? Sure, it's not of great scientific value, but it is nonetheless a property helium is noted for. I'd add it myself, but I forget the way it actually works...

--Furrykef 22:56, 21 Mar 2004 (UTC)

I'd like to see something about helium and the voice too. --Andrew 18:32, May 21, 2004 (UTC)

When discussing solid and liquid helium, the article claims:

helium vapor is very dense

Now, if that's true, it must be true in some very restricted way, since it's one of only two gases that are less dense than air at STP. Perhaps what is meant is that gaseous helium ad atound 5 K is very dense? That's certainly true; it'll expand 60 times going up to room temperature if it behaves like an ideal gas; does it behave like an ideal gas? --Andrew 18:32, May 21, 2004 (UTC)

safety

What about the effects of human ingestion? ~Resister 02:17, May 31 2004 (UTC)

Well, first of all it's a gas so ingestion is extremely unlikely. If ingested though, helium would not be expected to have any effect on the body because it is inert; it does not react with other chemicals. The only problem I could foresee would an expansion of the gas after ingesting a concentrated or cold quantity, which might cause pain and flatulence. That is an effect of any expanding gas though. - Centrx 18:55, 31 May 2004 (UTC)

I heard that inhaling helium, from balloons for example, kills brain cells. Anybody know? ~ Resister 23:01, 3 Jun 2004 (UTC)

While I am happy to accept there is no biological or chemical effect on the body of breathing helium, I think it would be responsible to mention its potentially fatal suffocating effect in the summary at the top of the article. I couldn't find how to edit the top section, but recommend "Helium is not toxic and has no biological effect, though it is possible to damage yourself through suffocation by breathing it excessively. See below." Steve Carter 3 Nov 2004

Yet, this is true of any substance. It's nothing peculiar to helium. - Centrx 20:43, 5 Nov 2004 (UTC)

"Guns don't kill people. Bullets do.", eh? Unlike many substances, helium has the appeal of being 'fun' - I added a caveat to the biological effects. Also replaced a different link for http://hoaxbusters.ciac.org/HBUrbanMyths.shtml#helium whose advice is just plain irresponsible. You may not even have time to notice before you pass out and crack your skull. Femto 20:12, 22 Nov 2004 (UTC)

Excessive inhalation of helium has the potential for injury as it has the same effects as excessive inhalation of any gas. In other words, the danger of helium in this respect is the same danger as that of any other gas, and that danger is a property of how human lungs suffocate. This is an encyclopedia, not a practical self-help guide where the article might explore the incidents of a thing that are not of that thing. It is far more relevant to include the injurious power of the bullet in an article on bullets, because the bullet is designed for injurious purpose, so the properties of the bullet proceed from injurious power. The properties of helium proceed instead from its physical composition, and its injurious power is incidental to its properties, rather than the cause of them. - Centrx 21:35, 11 Dec 2004 (UTC)

The gun analogy was merely to illustrate that if an article contains a safety-related statement that may be read as "guns are harmless", it shouldn't neglect to also mention bullets. I too think that no article on any substance needs an explicit warning not to choke on it, unless, the danger is real and reasonably common. That's why I still maintain the suffocation danger from helium as a party gag is very peculiar to helium (by definition), and that it is relevant to the subject. Femto 15:32, 12 Dec 2004 (UTC)

Narcotic effects of inert gases

Interestingly, most inert gases have an anaesthetic effect. Xenon, for example has been tested (and works well) as an anaesthetic gas, but is not used due to its expense. --Blainster 12:29, 1 Apr 2005 (UTC)

I never heard that before. Do you have a reference? Is it supposed to be all chemically inert gases (such as nitrogen) or only the noble gases? Xenon's anaesthetic effect is well-documented, but I haven't read about any others. --Andrew 05:43, Apr 2, 2005 (UTC)

Nitrogen is not an inert gas. It is not appreciably reactive at room temperature, but it is far from inert. At high pressures and temperatures, it will react with many compounds.

Darrien 06:03, 2005 Apr 2 (UTC)

The reactivity or inertivity (new word?) of a gas has little do with the narcotic effect. Also, this effect changes at different mixtures and pressures. Both inert and reactive gasses have such an effect, even pure oxygen. The exact mechanism is unknown, but some think, in the case of nitrous oxide or xenon, that it dissolves in the blood and causes displacement of oxygen. It is interesting to note, that some gasses are *less* narcotic than air (apparently)[1] (http://www.techdiver.ws/exotic_gases.shtml#6). Building a table of the exact narcotic effect at any pressure would probably end up a phase diagram for every gas. In the safety section of helium, one might mention only, that it is less narcotic than air, oxygen, or nitrogen. (Those kids who got suspended for sniffing helium at a school, under the school's zero drug tolerance law, could take that bit of info to court) Splarka 21:53, 9 Apr 2005 (UTC)

Yes, well, exciting as discussing the precise definition of chemically inert is, I'm still waiting for any kind of reference on the supposed narcotic effect. It's certainly not simply "displacing oxygen" (e.g. [2] (http://www.anaesthetist.com/anaes/drugs/xenon.htm): "Xenon inhibits the plasma membrane Ca2+ pump, altering excitability. It inhibits the nociceptive responsiveness of spinal dorsal horn neurons.") --Andrew 01:48, Apr 10, 2005 (UTC)

My point was, that whatever it is xenon does (when mixed proportionally with oxygen), helium apparently does it less than most gasses including nitrogen (which is what the majority of people inhale, with oxygen). This would mean it is not terribly important to mention in the safety section of Helium. Splarka 02:43, 10 Apr 2005 (UTC)

Does any gas other than xenon do it at all? --Andrew 03:16, Apr 10, 2005 (UTC)

Krypton, argon, and nitrous oxide. Read: [Exotic diving gasses (http://www.techdiver.ws/exotic_gases.shtml#6)]. It depends on the pressure and mixture. Of course, any non-oxygen gas can cause a loss of conscsiousness, due to lack of oxygen. These are different because they are mixtures of gasses that cause narcotic effects while still distributing the proper amount of oxygen to the body. Apparently even pure oxygen can do this in some cases. It is odd that helium is listed as less narcotic than nitrogen though. Does that mean breathing heliox would make humans less silly? Splarka 03:54, 10 Apr 2005 (UTC)

Okay, this is progress. Now, that page does not define what they mean by "narcotic". It has a specific meaning (see narcotic) but I think they mean nitrogen narcosis, which seems to occur upon exposure to various gases, not only nitrogen. Different gases lead to different problems:

nitrogen: nitrogen narcosis
oxygen: oxygen poisoning
helium: high pressure nervous syndrome
xenon: anaesthesia (even at ambient pressure)
nitrous oxide: anaesthesia (even at ambient pressure)

It looks (from the various references below) like any gas you breathe will potentially lead to nitrogen narcosis if the pressure is high enough for long enough, but some (oxygen, helium, chlorine, etc.) lead to other problems first.

To answer your specific question, helium doesn't make divers silly at all (party-goers, perhaps...). HPNS is rather different, and happens first.

This article (http://bja.oupjournals.org/cgi/content/full/89/1/17) describes (in very technical terms which I mostly don't understand) the mechanism of action of general anaesthetics. It gives figures for the anaesthetic partial pressures of argon (18 atm), krypton (4.5 atm), and xenon (0.95 atm). It also makes it sound like any gas that doesn't do something else first will have an anaesthetic effect.

This article (http://www.abysmal.com/web/library/articles/physiology_and_pysics_of_helium.html) or this one from the same site (http://www.abysmal.com/web/library/articles/mixedgases_and_diving.html) talks in slightly more detail about the narcotic effects of various gases.

In any case, none of this is relevant for helium safety; this discussion should maybe move to Talk:nitrogen narcosis. --Andrew 07:29, Apr 10, 2005 (UTC)

They seem to use the adjective narcotic in "the narcotic effect" and "narcotic factor", rather than the noun, simply for comparison. According to Websters: narcotic (adj) "1 a : having the properties of or yielding a narcotic b : inducing mental lethargy : SOPORIFEROUS". I would tend to say that is an accurate description in b of the effects of xenon, nitrous, nitrogen (at high pressure), and narcotics in general. Even the noun has the secondary definition of 2 : something that soothes, relieves, or lulls, leaving narcotic with no specific meaning, which easily applies to drugs, gasses, and watching C-SPAN.

But yes, this is just semantics, the answer to the original question is: helium does not have any noticable anaesthetic effect in the way xenon does (and I have yet to see two papers fully agree on how any gaseous anaesthetic works). If any mention is made regarding this in Helium, it should be in the lack of such effects. It might just prevent things like this! (http://www.azcentral.com/families/education/articles/0929gr-heliumZ12.html). How about "Although some noble gasses, such as xenon can cause anaesthetic effects at ambient pressure when inhaled, helium does not." This could prevent such strange conversations as we've just had. Splarka 08:52, 10 Apr 2005 (UTC)

I think a judicious reference to inert gas narcosis earlier on might be sufficient. After all, we can't warn against every idiot there is (not even the ones with law degrees). --Andrew 09:29, Apr 10, 2005 (UTC)

Helium, unlike Xenon is not an anæsthetic:

Xenon-atoms are so large that the outer electrons are only loosely attached. In water, the polar water-molecules polarizes the Xenon-atoms. The Xenon-atoms have many water-molecules statically clinging to them. The globs interfere with synapses and ion-channels. Helium-atoms are too small to polarize significantly. Theorectically, Radon is a better anæsthetic than Xenon because its atoms are larger and polarize more readily in water thus forming bigger better globs, but sufficient Radon to use as an anæsthetic would pose a definite radiological hazard.

— Ŭalabio 02:41, 2005 Apr 29 (UTC)

Well, if you follow the various links above (I know they're a mess) or go look at Inert gas narcosis, what you'll find at least one research paper giving a rather different description of what's going on. That's not to say your explanation is necessarily wrong; with a few minutes of searching I'm sure you could find several more research papers, each with a totally different proposed mechanism of action for xenon.

It seems to be the case that pretty much any gas you breathe will act as an anaesthetic at high enough pressure; xenon is just the right size (or something) so that atmospheric pressure (a little less, in fact) is enough to see the effect. Some gases, of course, have other problems first; helium causes high pressure nervous syndrome, for example. --Andrew 02:52, Apr 29, 2005 (UTC)

Although all gases under pressure cause problems, the forcing molecules through membranes of nitrogen-narcosis has different effects than than gumming up of ion-channels of the Clathrate of water and Xenon:

Nitrogen-Narcosis:: Paranoia and Vertigo

Xenon:: Loss of higher cognitive function leading to loss of consciousness

Nitrous Oxide:: Disassociation

Diethyl Æther:: Disassociation

High pressure nervous syndrome:: dizziness, nausea, vomiting

They are not all the same. I suspect that Clathrates of Xenon and water block ion-channels, gases (as opposed to Clathrates) interfere with the lipid-bilayer, and nitrous oxide and Diethyl Æther work chemically.

— Ŭalabio 05:21, 2005 Apr 29 (UTC)

Speed of sound

I changed the following statement: ...the speed of sound in helium is about twice that in air (at room temperature and pressure)... into ...the speed of sound in helium is about thrice that in air ... "about thrice" means: square root of ((Molar mass of air) divided by (Molar mass of Helium)), i.e. sqrt(ca. 31/4) = 2.8 This value is approximatly the same at nearly all temperatures and pressures. Malbi

I'm a bit confused with the above statement regarding the speed of sound in helium. If helium is less dense than air (which is what makes it lighter than air) and sound travels faster in a more dense medium (e.g. water and metal), how can sound travel faster in helium than in air? Michael

It sounds like a myth to me that the pitch change is due to the speed of the soundwaves in Helium. Can anyone explain exactly how? I would expect it to be more directly due to the mechanical effect of lower-density gas pushing through the vocal chords, i.e. their tension is proportionally worth more in the equation. This may indirectly come full circle to the speed of sound, but it remains a misleading explanation. Steve Carter

Basically: the frequency of your voice stays the same, but the vibration echo of your vocal chords down your throat gets less iterations, since the speed of sound is faster the waves become stretched (while staying the same amplitude) and therefor more 'hollow'. The opposite happens with a heavier gas (have access to xenon?).

To say it another way: "The voice sounds different because the natural resonant frequencies of cavities in the head are raised or lowered in proportion to the speed of sound. Of course the resonant frequencies of these cavities are only one ingredient in the way we sound. The gas does not alter the frequency of the vocal cords nor does it affect how fast we talk. The vocal tract acts as a filter for the sounds produced by the vocal cords in a manner similar to the treble and bass controls on a stereo." [3] (http://sprott.physics.wisc.edu/demobook/chapter3.htm)

That is, if you were to speed up the playback rate of your voice on a tape recorder, you would be changing the frequency. But, if you remove the bass and increase the treble, you would be changing the formant (simlar to helium). 64.162.11.244 23:22, 31 Mar 2005 (UTC)

Bad idea! Xenon is (mysteriously) a general anaesthetic - it could kill you! --Andrew 03:22, Apr 1, 2005 (UTC)

I like your explanation, though, it's perfectly plausible. But I'm not entirely sure it's correct - the vocal cords' resonant frequency is highly variable (and under muscular control). So it varies as you talk. In order to produce audible speech, you have to tune them to resonate at a frequency that produces a lot of sound. Som of this is determined by their shape, but some is determined by the resonant frequencies of the nearby cavities. So it may be the case that we instinctively tighten our vocal cords and raise the pitch in order to produce a sound when our voicebox is filled with helium. I don't know; we need an authoritative reference. --Andrew 03:22, Apr 1, 2005 (UTC)

It takes more than one breath of xenon to do that, apparently. I would trust breathing xenon more than sulfur hexafluoride, except for the price. Also, the vocal cords' resonant frequency does vary as we talk, but the frequency and amplitude are in direct relation to each other. More amplitude = lower frequency. All helium does is increase the speed of sound. I don't think helium would have any direct effect on the vocal chords except to make them very slightly more dense. In effect, it turns your head cavity into a smaller space as far as the echo is concerned. All modifications we do of that space are thus scaled down (or up with a heavier gas). If you listen to side by side wav files of a person speaking with and without helium, they are the same pitch. Also, if you have access to voice changing software that can change just the timbre you get the same effect.

1 part in 200,000

Could somebody please fix "only 1 part in 200,000"? What is that? Is it 5 mg/kg, or 5 µmol/mol, or 5 ml/l, or what? Gene Nygaard 23:42, 14 Dec 2004 (UTC)

The concentration is a dimensionless volume fraction of 0.00000524, you can work with any unit you like, m³, µl, or hogshead. m³ would be appropriate for gas volumes. However I'm not sure whether the article should give an accurate value "5.24×10^-6 m³/m³", or an approximation in natural language "1 volume part in 200,000". ('Volume' must be clearly said.) Any third opinions? Femto 13:30, 15 Dec 2004 (UTC)

Being gases it is of course also the molecular ratio... --Andrew 14:16, Dec 15, 2004 (UTC)

...which may be an additional convenient conversion, though my source ([4] (http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html) taken from Earth's atmosphere) is given "by volume", probably to avoid confusion with "by weight", which also seems like a good idea for the article. Femto 14:59, 15 Dec 2004 (UTC)

Recent edits

First of all, doing a total revert in which eminently valid edits are removed (for example, errant brackets) is not appropriate for a wiki and indicates a lack of consideration in the reversion. As for the other edits, they stem from the fact that this is an encyclopedia rather than a how-to guide, especially one on such a trivial and tangential topic as trying to change the pitch of one's voice by inhaling helium.

In the introduction, the reason that information is provided about the biological role of helium is because it is a significant characteristic of chemical substances that is often presented at the top-level in chemical data. Information about something so trivial as inhaling helium for voice change and which is extremely uncommon as a danger, however, is not. As a matter of introduction, it would be more appropriate to an encyclopedia to remove the biological information entirely than to leave it in the intro so hackneyed and so irrelevant.

As for helium hydrofluoride, this is theoretical and should be supported by some evidence in authoritative sources. Indeed, if one searches for "helium hydrofluoride" on regular Google or Google Scholar, there are no hits on the scholar, and the only hits on regular Google point to this article. Also, it would be unbalanced to present only helium hydrofluoride as a theoretical possibility when there are other theoretical possibilities, and possibly many others.

Sulfur hexafluoride has nothing to do with helium. The extensive talk about voice pitch changes is already rather tangential, and sulfur hexafluoride is a tangent on that. Even if it were valid, and it's not, there are other substances that affect the pitch of the human voice when inhaled.

As for the lengthy part about voice pitch changes, as I noted above this is not a how-to guide. An article in an encyclopedia presents fact--and should do so nonconvolutedly--whereas the section on voice change presents advice which, aside from being inappropriate for an encyclopedia, treads on some medical ethics. Wikipedia ought not present advice and, more importantly, it ought not present medical advice. So, while it may be appropriate to mention the possibility of oxygen asphyxiation in the article, it is not appropriate to recommend that, in order to prevent dangers to ones health, one should allow "a few minutes" of breathing before inhaling helium. Aside from that, it's a rather wishy-washy section as well so that, even if it were appropriate to make medical recommendations (and so generally at that), it is clear from the text that this advice is not coming from a medical professional. - Centrx 07:22, 8 Jan 2005 (UTC)

First of all, I did not do a total revert. Just look at the diffs to see that I approved many changes and mainly put back content which I think should not be removed to this extent without explanation or consent. (I liked the blimp image markup better with matched brackets—it actually displays the image...)

There are "noble gases", sometimes called "inert gases", but "inert noble gases" is rudundant and the grammar could be mistaken as if there were non-inert noble gases. It would be better to mention the inertness of helium through putting back "one of the least chemically active materials known". (Or the least chemically active material—it is easy to find on the web that noble gases are the least active of the elements, and helium is the least active of the noble gases, but not much about the general case. If somebody could confirm this please?)

"No biological effect" may have an unambiguous meaning in chemical data books, but in an encyclopedia it can be mistaken as "it can't harm you", so I'd agree it would be better to entirely remove the biological info—if the common classification nomenclature "simple asphyxiant" couldn't be worded and extended in a clear and encyclopedia-appropriate way. I don't see anything hackneyed or irrelevant at all here with "no immediate biological effect except possible harm through oxygen deprivation". Do you have a better way of saying "this stuff doesn't really do biological harm but you can suffocate on it"?
What happens when a commonly available gas is inhaled is certainly not irrelevant to an article about that substance, as you said, the biological effect is a significant characteristic. I would word it this way in the introduction for any simple asphyxiant. It has nothing to do with the voice changing properties of helium, how does this affect the relevance of the information in the lead paragraph? (Even then, helium is not an "extremely uncommon" danger. It should be easier and cheaper to come by for most people than many other gases. Helium plus a plastic bag is the tool of choice of some right-to-die proponents for assisted suicide for example. [5] (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12198347&dopt=Abstract))

Regarding helium hydrofluoride: search with various combinations of "helium", "helium compound", "HHeF", the alternative name "helium fluorohydride", or researchers "richard wong", "robert benny gerber", "chaban", "lundell", to see that this appears to be a well-founded and published chemical theory about which an encyclopedia can report in a factual way. I would prefer an only exemplary but specific mention of "HHeF", over a generic "other compounds" which discards useful information: you can begin a search from "HHeF" and "synthesis pathway", but not from "other compounds".

Regarding helium-3: nothing bad with the edit except one detail. Removing "captured" changed the meaning of what happens with the solar wind. The word should remain included in the article unless you have evidence to the contrary.

I'll explain why I had restored the voice change section if you explain what was meant with "due to oxygen deprivation caused by the of air normal for breathing" and "fatally pressure" vs "fatally overpressure".<p>Agreed on the sulfur hexafluoride, it doesn't really need to be mentioned. Though consider that removing such tangents only makes this section less un-relevant to helium and more likely to stay, instead of growing into a separate article. I also shall insist on saying perceived pitch, since it's just this distinction that's important here.<p>I read the voice section as a description of how a semi-scientific experiment is performed. (That's as much "how"-to as it gets, and I fail to see what's wrong with it.) It's an easily understandable demonstration of the biological and physical properties relevant to the subject of this article. It is relevant only to this article (you wouldn't do this experiment with hydrogen sulfide even if it were sold in balloons). It does not give medical advice, but states the factual medical information that one should need some fresh air after inhaling an asphyxiant such as helium is.<p>If it's clear that it's not coming from medical professionals (I hope that's clear. Wikipedia content is not professional advice, medical or otherwise, period. This does not mean however that we can't or shouldn't include such content.), what's wrong with keeping it? An article can't grow too much, but it can shrink too much. Even a wishy-washy section with admittedly not the best wording does not deserve to be reduced to nothingness, if there's a chance that it could be reworded and improved instead. Improving the bad—not removing it—is one of Wikipedia's main principles, isn't it?

Lastly, "with audio samples that demonstrate the unchanged voice pitch" would be a better link description than the too non-descriptive "regarding voice change" since the relevant feature of that site are those samples.

Femto 22:01, 8 Jan 2005 (UTC)

Yes, as I see now you did not do a total revert, but there were a few minor grammatical and formatic changes that were not retained. I don't know what you mean by the blimp and the brackets, but the brackets to which I refer were simply two, "]]", at the end of a sentence after a period which do not seem related to any image and which showed up in the presentation of the article.
Yes, it is redundant, but it is no more redundant than putting a sentence about chemical inactivity in the introduction. It should be changed to to "inert gases".
The point about suffocation is that pretty much anything that one inhales can suffocate. It is not something peculiar about helium, and if it warrants mention in helium then it warrants mention in numerous other articles where it is quite clear that it does not warrant mention. Death by inhalation of helium is extremely rare and there needs to be some evidence that it is somehow common for it to warrant mention in the introduction. There's no point in putting it in the introduction if it's not relevant to the element, and if suffocation would simply not have happened to anyone who read the article. The fact remains that the element has no effect on the biology of a human and the encyclopedia ought not cater to the lowest denominator of people, so low that they would not be reading an encyclopedia article on helium, who cannot keep themself from suffocating. The suffocation really requires repeated and determined effort, you can't just suffocate from inhaling two balloons even if one is right after the other. In order to suffocate someone really must go a minute or more without inhaling any oxygen. It's really just not a valid concern, and there needs to be some evidence that it is.
Okay.
The meaning using "capture" is simply wrong. The stellar object is not seizing or catching the particles, it is merely being bombarded by it. In astronomy, capture would be if the stellar object brought the particles into its gravitational field, when instead the bombardment would happen even if the object had no gravity, as the object is in the path of the particles being projected from the star. In physics, capture occurs when a particle absorbs another particle, and does not refer to stellar objects absorbing particles. The reason the particles are in the regolith is because the stellar object was bombarded and has nothing to do with capture. Putting both capture and bombardment in the same part is redundant and inaccurate.
It shouldn't be how-to at all, and the medical information is speculative, not factual, and makes recommendations to individuals, not general information on effects on the human body. What is the distinction of "perceived"? Are you saying that the helium has some effect on the listener's ear rather than on the pitch of sound released by the speaker? The helium changes the pitch of the voice because it changes the vibrations produced from the lungs, and that pitch would be changed regardless of whether there is anyone there to hear it.

- Centrx 22:59, 8 Jan 2005 (UTC)

Regarding inertness: Rather, it's not certain to be totally inert, which is why "noble gas" is used so today, but at the same time, the reason that it's redundant is because the reason that extra "chemically unreactive" information is there is because a reader might not recognize "noble gas" in the first place. Anyhow, I don't think that it possibly being hte least chemically reactive element known should be in the introduction anyway, and so belongs more in the body of the text with a more thorough discussion, rather than the silly trivial-pursuit style rankings that are really pretty...trivial. - Centrx 23:04, 8 Jan 2005 (UTC)

The brackets are the closing element after the caption of the image markup [[image:Goodyear.jpg|frame|right|Because of its low density, helium is the gas of choice to fill [[airship]]s such as the iconic [[Goodyear Tire and Rubber Company|Goodyear]] blimp.]] Trust me, I fixed it.

As a chemical group, "inert gases" doesn't seem to be as well defined as "noble gases", and it would make their link an awkward renamed redirection. How would be "one of the inert, noble gases of the periodic.." (note the comma)? Is the multiple adjective comma with a compound noun like this acceptable English grammar?

Retaining something after being hit by it certainly fits my definition of "capture", regardless of more clear definitions in physics or astronomy. Actually, I don't know much about lunar regolith, or whether the helium is simply retained from the solar wind, as opposed to being created by a reaction from the bombardment. I just want to remark that the word "capture" was previously used, and removing it did substantially change how I read that sentence.

I admit I like the conciseness of "Although this inhalation may be amusing, it can be dangerous if done to excess, as the helium displaces oxygen needed for normal respiration." which appears to be a good compromise between too much and too little. (I edited the ruptured lungs sentence a bit though.)

Yes, I'm saying the apparent pitch is influenced by the listener's psychoacoustic perception. Harmonics can pretend fundamentals that are not the same as the physical sound. (Take the missing fundamental phenomenon for example.) Strictly "speaking" (hah), helium does not make you speak higher but only sound different. Femto 18:46, 9 Jan 2005 (UTC)

The definition of "capture" you have in your head is not the definition supported by usage in English. The prime English definition of "capture" is one of seizing, it is an active taking rather than a passive bombardment (subjection to a stream of particles). In modified scientific usage, the astronomic and physical definitions are as I indicated, and do not fit the use as it was in this article.

The pitch of a sound depends on the rapidity of the vibrations of the medium (air). The helium changes the pitch of the voice regardless of whether it is perceived at all. To say that it changes the "perceived pitch" is to indicate that it does not actually change the pitch of the sound, only the perception of it, which is false. - Centrx 21:28, 22 Jan 2005 (UTC)

The rapidity of the vibration does, in fact, not change. What changes is the intensity distribution in the overtones of the main fundamental oscillation—which has no effect on the pitch by any meaningful physical definition. Still, helium voices are described as high-pitched because these unfamiliar harmonics are (but don't have to be, depending on the listener) perceived as an imaginary high pitch with yet another overtone spectrum. Femto 15:16, 23 Jan 2005 (UTC)

Perhaps a separate page like Voice changes with inhaled gasses or Inhaled gas vocal effects or such would be a good place to deposite this information, away from the elemental helium page. I notice the SF6 page mentions helium, but all possible gasses should be mentioned (krypton, argon, neon, xenon, propane, radon [6] (http://websql.physics.ucla.edu/demos/acoustics/effects_of_sound/voice_with_helium_and_sf6.htm) as well) on all such pages, or none at all. Such a page would also be a good place to discuss the actual result of the voice change, whether it be pitch, perceived pitch, frequency, amplitude, timbre, formant, or little green men (there seems to be no one answer, but I believe the "pitch" stated on the main page is incorrect, as that is just the perceived frequency). It could also be used to mentioned the use of increasing tape speed to fake Helium voice in media. This would not only unclutter the talk pages for each gas, but the main pages as well. 64.162.11.244 23:34, 31 Mar 2005 (UTC)

Anyone please keep this from happening??

HELP! Often, when I visit a Wikipedia article on an element, I get the article itself doing fine, but then, from then to the remainder of when Wikipedia is being used in the current window, each subsequent page has a not-loading background. Does anyone know how to help this?? Georgia guy 01:53, 18 Mar 2005 (UTC)

feedback to mav's expansions

The History section comes first and is almost one screenful of text. You're scaring them away, I tell 'ya! Put the Notable characteristics first, then it's close enough to the top to merge the "colorless, odorless.." introductions. Generally, much could be trimmed with some section regrouping. Several things are mentioned multiple times as asides to sections which they don't really belong in. The low boiling point is mentioned four times or so, and there may be some "superfluous superfluidity". (shoot me) There's a history/production and an occurence/production subsection, split by two other unrelated sections.

>> Helium in the form of alpha particles is radioactive. It can cause significant tissue damage, especially if inhaled into the lungs, even though thin cardboard can shield people from its effects.

If I'm not mistaken, it's not the helium that is radioactive. The danger from inhaling any radioactive alpha emitter substance is most specific to the lungs because that's an unlikely place to have some cardboard (or a few cm of air) between you and the radiation source.

Totally bogus. I removed it. (No naturally-occurring isotope of helium is radioactive; alpha particles are helium, as is mentioned about four times elsewhere in the article, but this has nothing to do with the safety of helium). --Andrew 05:23, Mar 31, 2005 (UTC)

>> It has a mobile, rapid flow through even capillaries 10^-5 or 10^-6 cm wide and moves in a 3 × 10^-6 thick film called a Rollin film

That's a funny choice of unit for these numbers (or none at all in the latter case).

>> Helium is chemically un-reactive under all normal conditions due to its valence of zero, meaning it has no free electrons which makes it an electrical insulator.

As opposed to, more reactive gases with non-zero valencies that are conductive? This is confusing.

Femto 22:20, 30 Mar 2005 (UTC)

I just saw your comments. Must go to bed now, but I've already reorganized this article to conform to WikiProject Elements standards (which has the notable characteristics section first). I'll go through and fix many of the other items later, but the the units you mention were the units in my reference for that (yes, the unitless number does need a cm). What SI unit do you suggest should be used?

100 nm–10 nm and 30 nm, or if the implied (non-)precision from giving just orders of magnitude is important, keep the exponent notation, but use m. Femto 11:19, 31 Mar 2005 (UTC)

Also, some characteristics should be repeated in different sections since different aspects of those features are talked about (this is especially true for the applications section where a characteristic is why helium is used for a certain thing). We also can't expect people to have read the whole article in order. But I'll still take a look to see if any repetitive info can be condensed or even eliminated. --mav 03:25, 31 Mar 2005 (UTC)

Actually, we should expect just that! Namely, that people want to read and need to comprehend not more and not less than the entire encyclopedia entry which they look up. The fact that an article can be read in parts, as though it contained different topics, is a sure sign that it is about different topics. Discovery, production, nuclear properties, superfluidity, vocal effect, etc.—it has become quite much for a single article. It may be time to split off some content into the common "Main article:" subsection format, with abstracts that outline all features once, just enough to understand the topic as a whole, and links to more detailed sub-articles which take the bulk off of the main page. Femto 15:02, 1 Apr 2005 (UTC)

This article is not nearly large enough for splitting and summary yet (talking about prose here - the table alone is ~5KB). See Wikipedia:Summary style --mav 16:50, 1 Apr 2005 (UTC)

I don't see a lower size limit though for summarizing the largest sections in order to avoid having to introduce some basic characteristics more often than once in the next higher detail level. Femto 20:17, 1 Apr 2005 (UTC)

Problems

>> Since helium has no free electrons heat is transmitted through it based on the element's quantum-mechanical character.

What is this supposed to mean? And does it apply to gaseous, solid, liquid, or superfluid helium? Shouldn't it apply to anything with no free electrons? (What is meant by a "free electron"? Solid argon has no free electrons either...)

Source: The Encyclopedia of the Chemical Elements, page 263 "Materials that are good heat conductors are usually good electrical conductors; however, helium has no free electrons and is an electrical insulator. It transmits heat by virtue of its quantum-mechanical character-...." It applies to helium II.

Fix: I simplified the version in the article to "Heat is transmitted through helium II based on its quantum-mechanical character." --mav

"based on its quantum-mechanical character" is pretty unclear. I rewrote it so that it says (I think) the same thing but should be more specific. I note that our heat articles are a mess. --Andrew 07:29, Apr 2, 2005 (UTC)

>> Helium solidifies only under great pressure, the variation of which can change the volume of its colorless almost invisible solid by more than 30%.

This is a cumbersome sentence. But I think it means that Helium solidifies under pressure. If more pressure is applied to solid helium, it compresses (like other solids). But once it's been compressed by 30%, something happens (what?).

Source: LANL.gov [7] (http://periodic.lanl.gov/elements/2.html) "Solid 3He and 4He are unusual in that both can be changed in volume by more than 30% by applying pressure."

Fix: "'Helium solidifies only under great pressure. Variations in the amount of pressure used to create this colorless almost invisible solid can affect its volume by more than 30%." -- mav

It sounds like what they mean is "using practical laboratory equipment, we can compress it by more than 30%", which is a useful statement (although not as useful as if they gave the pressures, or the bulk modulus). --Andrew 07:29, Apr 2, 2005 (UTC)

OK, now the bulk modulus is there, and it's really low (ie, highly compressible). --Andrew 19:47, Apr 4, 2005 (UTC)

Helium: It squeaks. It squirts. It's squishy! Femto (could not resist) 18:46, 6 Apr 2005 (UTC)

I'll get to the other sections of the page some other time. --Andrew 06:06, Mar 31, 2005 (UTC)

>> Although this seems paradoxical, it cools when it expands at temperatures below its Joule-Thomson inversion temperature.

What is its Joule-Thomson inversion temperature? Or is it pressure-dependent?

My source (The Encyclopedia of Chemical Elements, page 261) does not say. Here is what it does say though. "Helium, unlike most gases, heat upon free expansion at usual temperature (has a negative Joule-Thomson coefficient). When cooled to a sufficiently low temperature, to cools upon expanding. This is the Joule-Thomson inversion temperature, and is not accurately known." I left the 'not accurately known' info out of my version since this source is from 1968 and this fact may very well be accurately known now (my source gave a range of 32 to 50 K at 1 atm). A Google search (http://www.google.com/search?q=Joule-Thomson+inversion+temperature+helium&ie=UTF-8&oe=UTF-8) failed to uncover this datum, however. --mav

Bleagh. Well, I suppose we can't expect the Web to deliver every obscure little piece of data that we want. I'll try to check out a recent CRC handbook in the McGill library. --Andrew 07:29, Apr 2, 2005 (UTC)

40 K (At standard pressure, presumably. I don't know if or how big a difference it makes.), according to this Google cache hit [8] (http://www.google.com/search?q=cache:CoMqSs-5srEJ:edu.chem.tue.nl/6KM10/sheets/JTvalve.pdf) citing Atkins, Physical Chemistry, 5th edition, pp. 104-107. Femto 13:07, 3 Apr 2005 (UTC)

The way I (barely) understand it (and changed the article), this cooling is true for any gas and not exceptional. The notable characteristic is that unlike most other gases, He's JT T_inv is so low that it makes a difference at ambient T. Femto 13:07, 3 Apr 2005 (UTC)

OK, now there's an article at Joule-Thomson effect (and not just a stub) which explains a bit; Joule-Thomson coefficient and Joule-Thomson inversion temperature both redirect there. --Andrew 21:17, Apr 3, 2005 (UTC)

>> Its index of refraction is so favorable that helium gas is used to fill the space between lenses in high precision optical instruments.

Favorable in what way? Why is a near-vacuum IOR valuable? Perhaps it's because the IOR doesn't vary much with temperature?

Already answered in the ===Gas and plasma phases=== section (no need to repeat everything there with corresponding uses): "Helium's index of refraction is so close to unity that light passing through it is distorted less than than it would going through any other gas." Source: The Encyclopedia of Chemical Elements, page 261 " -- mav

Well, I had a problem with it there too - refraction does not "distort" light, at least not in a well-designed system. It bends it, in a completely predictable way. Perhaps the problem is chromatic aberration? Is there significant chromatic aberration due to air inside a high-quality telescope (compared to the significant chromatic aberration induced by the glass)?

Ah, it's thermal ripple they're trying to reduce, because it's in solar telescopes. Fixed. --Andrew 21:14, Apr 4, 2005 (UTC)

>> (there is a relatively high concentration of helium at 600 miles, about 1000 km).

How high is "relatively high"? Why does this occur?

My source (The Encyclopedia of Chemical Elements, page 257) does not say. This is what it does say "At a height of 600 miles there is a "layer" where the concentration of helium atoms is unusually high, compared with other elements at this level." --mav

It'd sure be nice to have some information about this. [9] (http://www.ux1.eiu.edu/~cfjps/1400/atmos_struct.html) and [10] (http://www.oma.be/BIRA-IASB/Public/Research/Thermo/Thermotxt.en.html) seem to provide enough information; the magic word is "heterosphere". --Andrew 07:29, Apr 2, 2005 (UTC)

>> In this way an estimated 0.5 ft³ (14 liters) of helium is produced from every cubic mile of the Earth's crust .

Per second? Per year? Ever?

Per year. My mistake. Fixed. --mav

>> There is one He-3 atom for every million He-4.

Where? Is this in the Earth's crust, in the atmosphere, in the ocean, in the universe?

My source (Nature's Building Blocks, page 178) did not say. Here is what it did say: "Helium has two stable isomers [sic], helium-4 and helium-3, although there is only one atom in a million of the lighter isotope." To me that means 'in the Universe', but since my source did not say that, I didn't guess. --mav

Helium isotopic abundances vary depending on the origin: :::*[11] (http://www.grisda.org/origins/25055.htm) (by a creationist no less!) claims that cosmogenic helium has a He-3 proportion hundredsof times higher.

This peer-reviewed paper (http://www.ingentaconnect.com/content/klu/asys/2002/00000045/00000002/00378626) gets a He-3/He-4 ratio of 1.7·10^-4 in the local interstellar medium (compare with our ratio of 1.37·10^-6, which is for the Earth's atmosphere).

>> Equal mixtures of liquid He-3 and He-4 below 0.8 K will separate into two immiscible phases due to their dissimilarity.

What sort of dissimilarity? Simply the mass, or some quantum-mechanical magic? Or is it that one becomes a superfluid and that quantum-mechanical magic expels the other kind of helium?

The Encyclopedia of the Chemical Elements, page 264 says that it is due to each following different quantum statistics (whatever the hell that means - that's why I didn't add that info before). Info added. --mav

The magic buzzwords are boson and fermion, which I have at least a tenuous understanding of. Also discussed on Helium-3 and Helium-4 --Andrew 07:29, Apr 2, 2005 (UTC)

I've also fixed a few things I was pretty sure of. --Andrew 06:55, Mar 31, 2005 (UTC)

Good job. Thanks. :) --mav 05:05, 2 Apr 2005 (UTC)

Well, I would never have expanded it to its current size, so hopefully if we both keep hacking at it it'll get a lot better. --Andrew 07:29, Apr 2, 2005 (UTC)

>> There is only a trace amount of helium-3 on Earth, produced from the beta decay of tritium, and from the decay of lithium.

What isotope of lithium? The usual ones are all stable.

I don't think I wrote that. But a simple check finds that it might be wrong. [12] (http://environmentalchemistry.com/yogi/periodic/Li-pg2.html) Looks like it is proton emission from lithium-4 (not sure where the extra neutron goes though..). Fixed. --mav

There's no extra neutron; you have just the right collection of nucleons. But Li-4 is synthetic, so if it's making He-3 something has to be making it. [13] (http://environmentalchemistry.com/yogi/periodic/He-pg2.html#3) lists no naturally occurring parent nuclei. I think He-3 is not being made in the Earth; what there is is diffusing upward from the lower mantle and core where it has been since the Earth formed. But I'm not sure. --Andrew 07:29, Apr 2, 2005 (UTC)

I took this out; if we find other ways helium is produced we can put them in, but decay of lithium-4 looks unlikely. --Andrew 20:47, Apr 5, 2005 (UTC)

>> Even though the creation of helium in the crust is fairly uniform,

Doesn't it only occur where there are uranium deposits? On what scale is it uniform?

For god's sake. The reason is due to the fact that uranium is found fairly uniformly in the crust (I don't know about the other alpha emitters - thus I did not say anything about parent isotopes). See uranium#Production and distribution. My source did not indicate the scale of uniformity and frankly why the hell would an encyclopedia article need to go into such detail about something that is not directly related? That is more appropriate for the uranium article. --mav

The article currently gives the impression that all rocks contain about the same fraction of uranium, which is just not true; uranium-bearing minerals occur in veins, and the distribution is sufficiently non-uniform for natural nuclear reactors to occur (Oklo, in Gabon). So a claim that the uranium is uniformly distributed is a little dubious. Maybe all cubic miles of the Earth's crust have about the same amount of uranium (that is, the veins are smaller than that and evenly distributed?) I think the key fact is that helium is obtained not from places there's uranium but from places there's natural gas. The uniformity of uranium is, as you say, a side issue. But I think we should be careful not to mislead. --Andrew 07:29, Apr 2, 2005 (UTC)

I found a reference that talks about the geology; the distribution of U+Th is not uniform, so I tried to clear up the story. --Andrew 20:47, Apr 5, 2005 (UTC)

Remaining problems

>> the United States whose National Helium Reserve is by far the largest supplier of the gas.

Is this still true? They're supposed to be phasing it out starting in 1996 (according to the article).

Argh! I'll have to look into that later (too many contradictory sources). --mav

According to [14] (http://www.nap.edu/openbook/0309070384/html/index.html), the actual selling isn't supposed to start happening till this year and nobody wants it anyway - commercial users just take the stuff from natural gas deposits. On the one hand this suggests that they're still the biggest stockpiler of the gas, but on the other it suggests nobody's buying it from them. I haven't read the whole book, though. --Andrew 21:02, Apr 5, 2005 (UTC)

Fixed. --mav

>> Due to its very poor solubility in water (the least soluble of any gas), it only makes up 4 parts per trillion in seawater.

Does this actually have anything to do with solubility? Is 4 ppt really the solubility, or does the stuff just outgas when uncovered?

Yes it does have everything to do with solubility. See the cites and remind yourself of the bonding properties of this element. --mav

I know it doesn't dissolve easily. But there's so little in the atmosphere that even if it were soluble, it might just leave the water and pass into the air, where it would escape the Earth entirely. Is the solubility of helium really as low as parts per trillion? This Material Safety Data Sheet (http://www.matheson-trigas.com/msds/MAT10640.pdf) gives a solubility figure of 0.98% at 0 C (I don't know what the percent is of, maybe molecule ratios again, but in any case it's more than parts per trillion). So I don't think the low solubility has much to do with it. Think of it this way: oxygen is pretty soluble in water. But if you close a canister with water and air, and then keep scavenging all the oxygen from the air, by the end there won't be any left in the water either.

I deleted the reason from the article; I'll be happy to put it back after we discuss it here. --Andrew 07:29, Apr 2, 2005 (UTC)

Billion and trillion are ambiguous (not just here). Volume parts or mass? Small liquid concentrations are usually in µg/L or ng/L. Femto 11:57, 31 Mar 2005 (UTC)

Volume parts or mass? What do you mean? It means exactly what it says. But let me spell it out for you: 1 helium atom per trillion molecules of everything else in seawater. See the trillion and billion articles to learn about their current usage. But for those still stuck in 19th century England I've parenthetically put 10⁹ and 10¹² behind their corresponding words. --mav

ppt sometimes means parts mass per trillion parts mass, especially when the two things being measured are heterogeneous mixtures of molecules. --Andrew 07:29, Apr 2, 2005 (UTC)

It could mean either one kg of helium per one kg of seawater, or one dm³ of helium gas at STP per one dm³ of seawater, or one mole of helium atoms per one kg of seawater divided by the weighted averages of its molecular masses. You're not suggesting that Germany, Spain, The Netherlands, Hungary, Sweden, Denmark, Norway, Finland, etc. are stuck in 19th century England because their current usage is to associate a different number with one billion? The terms are language dependent and potentially confusing in international writing. Both ambiguities can be avoided by finding an appropriate unit. Femto 13:04, 2 Apr 2005 (UTC)

The language here is English and there is disambiguation behind the terms. That is fine the way it is. --mav

I'm now pretty sure that solubility is not the reason for the small amount in the oceans. If you're happy with that I think we're done with this complaint. --Andrew 03:40, Apr 6, 2005 (UTC)

Right, but there still remains that "parts per" concentrations are meaningless if they're not defined in terms of which part is meant of what part. Femto 18:46, 6 Apr 2005 (UTC)

>> Helium I contracts with lowering temperature and boils with heat input until it reaches the lambda point, when it suddenly expands and stops boiling. Expansion decreases below the lambda point to about 1 K when it ceases entirely and starts to contract again.

I don't understand this sentence at all.

Source: The Encyclopedia of the Chemical Elements, page 263 "Liquid Helium I contracts with lowering temperature till the lambda point is reached; at this transition temperature the liquid suddenly expands. The rate of expansion decreases as the temperature is lowered below the lambda point, and at about 1°K the expansion ceases entirely and the normal contraction displayed by Helium I returns." and ".... Helium I exhibits the usual boiling of a cryogenic fluid due to heat input into the system. When the temperature reaches the lambda point the boiling stops immediately and the liquid is very quiescent."

Fix: Now that I look at it, I think I tried to put too much information in too few sentences. New wording "Like other cryogenic liquids, helium I boils when heat in added to it. It also contracts when its temperature is lowered until it reaches the lambda point, when it stops boiling and suddenly expands. The rate of expansion decreases below the lambda point until about 1 K is reached; at which point expansion completely stops and helium I starts to contract again." --mav

Now I'm dubious. Normal liquids boil when heat is added if and only if they're at their boiling point. Liquid nitrogen is the same. Is liquid helium somehow different? If the lambda point is independent of temperature, perhaps they're talking about cooling the liquid and also changing the ambient pressure so that it always remains at its boiling point? (Pumping out the gas above would have this effect, and is almost certainly a good idea). I suppose that if the fluid is at the lambda point, heat goes into changing the state from helium I to helium II. (And not into boiling the liquid) --Andrew 21:17, Apr 3, 2005 (UTC)

I don't know. What I got from the sentence is that cryogenic liquids boil whenever heat is being added. --mav

Well, that's not true; but as we say in the article, helium II doesn't boil, it evaporates (because of its heat conductivity). So liquid helium really does stop boiling when it turns into helium II. --Andrew 03:40, Apr 6, 2005 (UTC)

>> and moves in a 3 × 10^-6 cm thick film called a Rollin film, named after the man who first characterized this trait, B. V. Rollin.

Under what circumstances does it move in the film? Is this when it's flowing along a surface with one boundary free in a vacuum? Is this the thickness of some sort of boundary layer?

Source: The Encyclopedia of the Chemical Elements, page 263 [immediately following a description of what happens when helium II is put into a cup - a description I didn't understand and thus did not include] "The liquid flows in an extremely thin layer, or film, only 3 x 10^-6 cm thick. The film is called the "Rollin film," after B.V. Rollin, who first studied and characterized it." [Then, getting back to the cup description] "The rate of transport of helium in the film is almost completely independent of the nature of the cup material or the height of the cup. Helium II is thus called a "superfluid" and the phenomenon is termed "superfluidity." "

Fix: I've changed sentence in this article to "When in contact with a surface it moves in a 3 × 10^-6 cm thick film regardless of surface material and seemingly against the force of gravity (when in a cup, it can escape by moving up the sides of the cup). This film is called a Rollin film and is named after the man who first characterized this trait, B. V. Rollin." --mav

Under what conditions does this occur? I think the story of the cup might be important. Is this a phenomenon analogous to capillarity, in which it will crawl on its own, or it it the self-siphoning effect (which needs an established liquid film to continue)? Certainly if you pour it along a surface it may well flow in a much thicker sheet. --Andrew 07:29, Apr 2, 2005 (UTC)

Okay, details added for this and the fountain effect. We may want to move some of this to superfluid or Helium II. Do you have a reference for the claim that it moves toward a heat source because of its thermal conductivity? I know the Rollin film effect can cause creep toward a heat source. Are you sure that the thickness of the film is independent of surface composition? The flow rate seems to be (from your quote) but that doesn't imply the thickness is. --Andrew 20:51, Apr 4, 2005 (UTC)

Source: The History and use of our Earth's Chemical Elements, page 208 "Second, it is an excellent conductor of heat. As a supercold liquid, it will move toward heat - even flow up the sides and over the top of a container." This is the same source that also said "The nuclei of helium atoms are called alpha particles, each of which has a charge of +2 and an atomic weight of 4." Skimming the source, I also noticed some other things that you've caught. I've come to realize that using this source was a mistake and recently read a very bad review of this book: "Now, even a remedial book of this sort would be nothing to sneer at, and I would have rated it much, much higher were it not for the fact that, not only does it offer but a smidgeon of information about each element, but that information is badly written (often quite prolix), and worse, replete with the most glaring inaccuracies and downright errors! (http://www.amazon.com/exec/obidos/ASIN/0313301239/104-2672701-1698341)" So it appears this source is worse than useless, and I will therefore just throw it away. I've also removed the disputed "fact" gleamed from this source. If you see an inline cite for this ref, then be extra critical of the cited content. --mav 01:11, 6 Apr 2005 (UTC)

>>Helium was first liquefied by Dutch physicist Heike Kamerlingh Onnes in 1908 in Leiden by cooling the gas to less than one kelvin. He tried to solidify it by reducing the temperature to 0.8 K but failed because helium does not have a triple point temperature where the solid, liquid and gas phases are at equilibrium.

Indeed it does not have a triple point[15] (http://www.speclab.com/elements/helium.htm), but what does this have to do with solidification? It didn't stop his student... it sounds like he just didn't apply enough pressure.

It's also the case that helium has a triple point of another sort, at which helium I, helium II, and gaseous helium coexist[16] (http://hyperphysics.phy-astr.gsu.edu/hbase/tables/phase.html). --Andrew 03:40, Apr 6, 2005 (UTC)

Danger of alpha particles

I think it's highly misleading to put alpha particles in the "helium safety" section. Alpha particles are not produced by helium in any form; ionizing helium does not produce alpha radiation, and inhaling helium is not dangerous. Inhaling alpha particles is impossible, as they are moving at high velocity. If they slow down, they immediately de-ionize and become safe helium. I'll try to rephrase things so they are not too misleading.

For comparison, high-velocity beams of any ion are exactly as dangerous as alpha radiation; most do not occur naturally. --Andrew 18:32, Mar 31, 2005 (UTC)

+2 helium ions are alpha particles. --mav 07:02, 2 Apr 2005 (UTC)

No! All alpha particles are helium ions, but not all helium ions are high-energy particle radiation from alpha decay. Femto 13:06, 2 Apr 2005 (UTC)

My bad - I majored in biology and minored in geology. :) --mav

Actually - that came from a very bad source. See above. --mav 12:03, 6 Apr 2005 (UTC)

From the EPA (http://www.ingentaconnect.com/content/klu/asys)

What are the properties of an alpha particle?

An alpha particle is identical to a helium nucleus having two protons and two neutrons. It is a relatively heavy, high-energy particle, with a positive charge of +2 from its two protons. Alpha particles have a velocity in air of approximately one-twentieth the speed of light, depending upon the individual particle's energy.

In other words, if it's not fast-moving, it's not an alpha. --Andrew 22:52, Apr 2, 2005 (UTC)

I deleted the paragraph about alpha particles. It is unfortunate that the general precautions for helium and a description of the vocal effect share the same section. Should we be listing the general precautions here at all? What does "Containers of helium gas at 5 to 10 K should be treated as if they have liquid inside." mean anyway? Jan van Male 06:26, 7 Apr 2005 (UTC)

And why did you delete that paragraph? Yes - precautions should be listed in this article. Read the rest of the para: "This is due to the rapid and large increases in pressure and, if allowed, volume that occur when helium gas at that temperature is warmed to room temperature." -- mav 10:09, 7 Apr 2005 (UTC)

I deleted the paragraph on alpha particles because I agree with Andrew that speaking about alpha particles in a helium safety section is misleading. From the above discussion I got the impression that the paragraph was originally included because of a misunderstanding. Namely that He is a source of alpha radiation, which it is not. I concluded that there was consensus on this issue but apparently I was wrong.

Let me clarify my issues with the precautions a bit further. I believe it is necessary to warn about the possible health risks when performing the vocal effect trick and clearly such a warning should be next to the description of the effect. Of the other two remaining warnings one is specific to divers and the other to treatment of storage containers containing low temperature liquid helium. The diver warning could be moved to the paragraph on heliox (but essentially is already there). My question is do we want warnings about the treatment of storage containers? There definitely is more (http://www.camd.lsu.edu/msds/h/helium_liquid.htm) to add but I'd say it is not encyclopedic.

I still maintain that "Containers of helium gas at 5 to 10 K should be treated as if they have liquid inside." does not tell me anything. Call me dense but I don't get how to treat something as if it has liquid inside. What does it mean? Jan van Male 14:58, 7 Apr 2005 (UTC)

Some remarks after a lot of improvements

First of all: I'm impressed by the rate of improvements on this page. The coverage and quality has vastly improved since this was nominated as FA. Some remarks:

I wondered whether you are aware of the Liquid helium page and the request for a merge with this page. I guess we could merge liquid helium with helium-3 and helium-4 and delete/redirect.

Oops! No, I wasn't. It looks like it should be folded into this page, or a "Main article: liquid helium" tag could be added to this article, and we could move some of our content there. Liquid helium contains information about both He-3 and He-4 as well as their miscibility; I don't know which of the superfluid properties work for He-3. --Andrew 23:41, Apr 6, 2005 (UTC)

Offloading some of the detail to the liquid helium article was my plan all along. Please proceed but leave a summary here. --mav

I'd like to see a phase diagram as shown here (http://boojum.hut.fi/research/theory/helium.html) but maybe they belong in the helium-3 and helium-4 articles.

Me too, but I don't know that to do about copyright issues - we certainly can't collect the data to make our own, and effectively tracing somebody else's seems pretty dubious from a copyright point of view. Some abortive searching for a free one went nowhere, but there's some hope a US federal government agency has posted something.--Andrew 23:41, Apr 6, 2005 (UTC)

(I am not a lawyer.) I don't see how the relative position of lines in a diagram could be copyrighted whose shape is uniquely determined only by descriptive physical property data. Attribute the source to make sure, but as long as we don't copy the exact image or any creative content like colors, text style or placement and such, tracing the plotted lines should be fair use, if anything. Femto 14:14, 7 Apr 2005 (UTC)

The crystal structure as shown in the picture at the top right of the page is the most important structure, there is also a body centered cubic phase. This affects at least one other element (carbon). Are there more and what is the best way to deal with this?
- Mention this in the crystal structure part of the table (not the image). --mav
From the solid and liquid phases section: "The rate of expansion decreases below the lambda point until about 1 K is reached; at which point expansion completely stops and helium I starts to contract again." Something is wrong here. Liquid helium of 1 K is below the lambda point, therefore it is helium II. However, the second part of the sentence does not reflect this and it seems more than a typo. What is intended here?
The transition between helium I and helium II appears to be not at a fixed lambda point but rather at a lambda line see here (http://www.fluidmech.net/msc/super/super-f.htm)
- At any particular pressure it is still a point. This is also true for any other phase change. --mav
When speaking about the low density of liquid helium: "which is only 1/4th the value expected from classical physics". How does classical physics predict densities of liquids?
- Encyclopedia of Chemical Elements did not say. --mav
"This is probably due to its boiling point being so close to absolute zero" It would be nice to know whether wikipedia is unsure or that scientists don't know the cause of this effect.
- That statement was based on the ref given in the corresponding para. --mav

Jan van Male 23:18, 6 Apr 2005 (UTC)

"The coverage and quality has vastly improved since this was nominated as FA." Gee - thanks a lot for noting the original major expansion that got us here to begin with (expansion since then has in fact been minor). I won't be expanding any more element articles for a while. --mav 10:15, 7 Apr 2005 (UTC)

I'm sorry for not mentioning your large contribution. Be sure it is appreciated. I'm fairly new here and jumped in after the FA nomination and didn't look at the history but simply at what was there at the time. I was and am impressed by the rate of improvement since then on a rather specialised and sometimes difficult subject. That the rate was even higher before ... I was simply unaware. Jan van Male 13:51, 7 Apr 2005 (UTC)

My mistake then - I'm just a bit shell-shocked by the unexpected amount of rework that had to be done due to using a bad source. --mav 16:19, 7 Apr 2005 (UTC)

periodic table at top

Why is the first picture that jumps in the reader's eye the periodic table? Is this really the most important thing to show about helium? Someone who looks up "helium" and cares about where it is in the periodic table will - in all likelyhood - already know where it is. For someone who doesn't know already, the little image probably isn't very useful, either. To add to the confusion, "He" (and "Ne") are written to the left(!) of the table.

That is the standard format for all elements' pages, so should not be changed just for one of them. The link to Neon is the element directly below Helium on the PTOE. It makes more sense for an element like Rhenium where you can see the full effect. Elements with similar bonding sites have very similar properties, so knowing the next/previous element vertically is very useful. Splarka 01:11, 7 Apr 2005 (UTC)

Good point: It does make sense for Re, and there is value in consistency. So it should be in the article somewhere. But why in the top space? (and why with "Hydrogen" as its first link?) If I may compare the position of an element in the periodic table with the location of a city: The article London doesn't start with a world map, and it doesn't prominently feature a link to Slough.

Well, I more meant it being at the top (along with having the links to above/below) was the standard, not just having such an image. All the elements seem to have it at the top right (except for notices, disambiguation, etc). If there were significant meanings of Helium that had little/nothing to do with the element, then I can see where such a case might be argued (as for Mercury, but that gets a disambiguation page). But since helium is mostly found as a monatomic gas in elemental form (excluding compounds and ionized radiation), helium is one of the most elemental elements we deal with regularly. As for hydrogen, all elements have a link to the elements above/below and to the left/right on the table. For helium, only neon and hydrogen are in such relations. I think if you have an overall problem with this, you might bring it up in Template talk:Element, Wikipedia talk:WikiProject Elements, or Talk:Periodic table. I find it useful when comparing elements, to have such information readily available. Splarka 01:01, 8 Apr 2005 (UTC)

Thank you - you're right, it shouldn't be discussed here. Should we delete it from this page?

I am not sure. Other people might ask the same question on a page about elements rather than in a general element forum (like the PTOE page). If so, this would be the second best place for them to find this discussion (the other being hydrogen). If anyone who is part of the Wikipedia talk:WikiProject Elements wants to move or delete this section, feel free (I am too n00b to make such a decision). Splarka 22:14, 8 Apr 2005 (UTC)

No - that image should not be deleted. It is used to navigate the periodic table, to quickly tell the reader where they are in the table, and to present other data. --mav 12:21, 9 Apr 2005 (UTC)

I mean, delete this section of the discussion. Splarka 21:05, 9 Apr 2005 (UTC)

Ah - not that important either way. --mav 01:34, 10 Apr 2005 (UTC)

Compressibility of Helium

Q: Hello.

Can anyone help me with this? There are small helium canisters sold that can be used to inflate your own party balloons. I think a canister that is about 14" tall x 12" dia. round can inflate about twenty 18" diameter balloons. How big or small would a canister of helium be that would inflate either one or one-hundred balloons? In other words, I don't know if it's a straight ratio or what. Would it mean that the volume in the 14" tall canister can be divided by 20 balloons and that would give me the compressed volume needed to fill just one balloon? How big would a canister be that fills just one balloon and how big would it be to fill 100 balloons?

Thanks for any help.

A: Yes, you're correct. It's linear. So a 6" tall by 4" dia. canister would hold enough for one balloon, and you'd need a 25" by 20" to fill 100 balloons.

Of note is that you'd need to adjust your math for outside pressure. If you completely empty a canister, you need enough helium to fill both the balloon and the canister (as the canister will stop filling the balloon when it equalizes with the outside pressure). So: If you had a canister exactly the size of your balloon, you'd need twice the pressure in the canister as out, to inflate it. If it was 10 times smaller, you'd need 11 times the pressure. If it was twice as big, you'd need 1.5 times the pressure. Also, it is linear, until you get enough pressure to liquify it (but there is not much danger of that with most helium you will encounter). Also of note: those low pressure cheap disposable party cansiters have oxygen in them, to prevent kids from suffocating who breathe the air, as well as save money on helium. They don't have as much lift as welding grade helium (which comes in tanks pressurized at about 2000 PSI). Splarka 22:32, 8 Apr 2005 (UTC)

A2: it might be linear. If the pressure inside the tank is the same, then a tank that is twice as big holds twice as much. But the big monster tanks are likely to be at a different pressure than the kids' party tanks; if as Splarka suggests, they are partially full of oxygen too, this may confuse your calculations.

For big tanks, they are actually listed by their capacity, not by their physical size - for example, you might get a 300 cubic foot tank (a common size), which would contain enough helium to fill 300 cubic feet of balloons (in fact a bit less since balloons are somewhat over atmospheric pressure). --Andrew 05:18, Apr 9, 2005 (UTC)

nationalities and obvious occupations

Maveric149 wrote: "putting nationalities back ; no harm in having them here and nationality is very important in the history of elements".

Q: Why do you find it very important in the history of elements? I understand that some people take great pride in the achievements of their compatriots and I don't want to discuss the merits or shortcomings of this position. People are different; they have all sorts of hobby horses. Other people e.g. would be interested in knowing how many of these were white males. This sort of information can be looked up in the individual people articles. Each of these interests can be important in their own right, but what does this have to do with helium in particular? I am not sure if there is really no harm done by inserting nationalities where they are redundant, but this is not my point. I think a good encyclopedia article should go beyond avoinding harm. It should try to express as much pertinent information as possible, and separate the chaff of information glut from the wheat.

Also, what do you think is gained by inserting obvious occupations, such as "chemist"?

Minor questions:

why do you call someone who is born in London "English" and someone who's born in Glasgow "British"?
Is "Swedish chemists Per Teodor Cleve and Abraham Langlet in Uppsala in Sweden" really an improvement? Uppsala University is arguably the best known university in Sandinavia, and Uppsala already has a link to sweden, for those who don't know.

Thank you!

The history of the discovery of the elements has always been very competitive between nations. Also, every source I've used to expand this article has mentioned the nationality of the person making whatever discovery. Doing this is a very common practice outside of Wikipedia and is done for every element I know of here in Wikipedia. Lastly, that info does not take up much space, we should not expect each user to to click on the names, and the info here helps to contextualize (very few people know who the scientists are, but a great many will know something about the nation the person was in). --mav 12:04, 9 Apr 2005 (UTC)

Molar volume

I believe the value listed for the molar volume is a copy from webelements.com. Comments on the validity of the value can be found here. Looking at webelements suggests that the value does not refer to a solid phase, since they also do not list the density of the solid. Listing the molar volume of the solid phase here is not very helpfull because helium is 1) only solid at very extreme conditions 2) highly compressible as a solid. Now if someone can come up with reliable data for the molar volume at the gas phase... Jan van Male 22:38, 8 Apr 2005 (UTC)

All gases have essentially the same molar volume at STP (22.4 liters?) up to tiny variations based on intermolecular attraction (only relevant if the gas is nearly liquefied). Observe that, as a random sample, chlorine gives a molar volume that has to be for some sort of liquid or solid. Both Wikipedia:WikiProject Elements and the the original WebElements source fail to define what they actually mean by the molar volume for gases; I posted a comment on our WikiProject Elements page hoping someone will help. --Andrew 05:13, Apr 9, 2005 (UTC)

That was me who added "(solid)" here, based on the calculation 4.003/21.0=0.19, a quick web search result (http://216.239.59.104/search?q=cache:vc779XQv0CMJ:www.lps.ens.fr/~balibar/acoustic.pdf+%22solid+helium%22+density+%220.19%22&hl=en) saying the density of hcp solid helium is 0.19 g/cm³, and the rationale better have something that might be wrong for now than something that definitely is misleading. More at Wikipedia Talk:WikiProject Elements later this day. Femto 12:30, 9 Apr 2005 (UTC)

p-block? s-block?

Is Helium in p block? It should be s-block. ChongDae 06:39, 28 Apr 2005 (UTC)

Good catch! Corrected now, thank you Jan van Male 16:16, 28 Apr 2005 (UTC)

I thought the s-block was the first 2 columns of the periodic table (the alkali metals and alkaline earth metals.) Is helium really one of these kinds of elements?? I always thought it was a noble gas. Georgia guy 21:13, 26 May 2005 (UTC)

Did this question get sorted? Looking at s-block, Helium isn't included. Someone has changed Periodic table (block) to exclude it. Noisy | Talk 12:59, May 29, 2005 (UTC)

It's s-block in the sense that in the ground state both of it's electrons are in s-orbitals, but of course it doesn't behave at all like the other s-block elements. They easily lose electrons from their loose outer s orbit, that makes them chemically active. But Helium only has the S-orbit, and it is full, so it doesn't easily accept or lose electrons, making it inert. The best solution is probably to group Hydrogen and helium together into "s-block oddities".Zeimusu | (Talk page) 14:11, 29 May 2005 (UTC)

natural abundance

The reasons why the word '(atmospheric)' doesn't belong in the dialog box:

The dialog box is unform across all because it was agreed on by the wikiproject.
The article on natural abundance specifically states that The abundance of an element varies from planet to planet.
The natural abundance would be the same if it existed in the core of the planet so the descriptor ("atmospheric") wouldn't work for other elements.

--User:Sunborn/si 04:02, 5 May 2005 (UTC)

Well, no, actually. To quote from the article:

Rocks from the Earth's crust have isotope ratios varying by as much as a factor of ten

That number really is only correct for the atmosphere. Or at least, if you have a good number in front of you, you should check where it's for, because it really does vary a lot, and for a good reason. Uranium and thorium distributions vary and rock permeability varies, so the amount of He-4 that has formed and/or been trapped varies; the amount of primordial He-3 also varies, in different ways.

This is a common problem with the tables of data we have used for element and isotope data; they don't record enough information to tell what the measurement is of. For isotopic abundances, it mostly won't matter (as long as you look at terrestrial numbers) but helium is an exception. (Technetium also). --Andrew 04:34, May 5, 2005 (UTC)

So then, we have two options, add the word atmospheric which would not be according to the template or set He-4 to 100% and put He-3 to 'trace'. I prefer the latter for the sake of uniformity. --The Sunborn

Uniformity is just not that important - it's certainly not worth removing useful information over. We already have all sorts of necessary deviations from the infobox format - for example, we give a pressure for the melting point of helium since it does not solidify at ambient pressure. No other element does this. --Andrew 15:33, May 5, 2005 (UTC)

Redudancy

I was about to pull these sentences out until i realised that the article has been featured. I will therefore not temper with the article but can't help but feel the the gas use has been mentioned way too much. Pulling this peice off may improve the article. "Helium is used in cryogenics, in deep-sea breathing systems, to cool superconducting magnets, in helium dating, for inflating balloons, for providing lift in airships and as a protective gas for many industrial uses (such as arc welding and growing silicon wafers). Inhaling a small volume of the gas temporarily changes the quality of one's voice." gathima 01:45, 8 May 2005 (UTC)

Companies producing helium

Does anyone know the name of the companies that produce the gas? The only pertinent piece is this. "After the "Helium Acts Amendments of 1960" (Public Law 86-777), the U.S. Bureau of Mines arranged for five private plants to recover helium from natural gas."

Information on unstable isotopes

User:Sunborn had removed the information on stablites of synthetic isotopes of Helium. I reverted. Is there any special reason why we shouldn't include this information.? Zeimusu | (Talk page) 07:16, 18 Jun 2005 (UTC)

It has been decided in the two wikiprojects of Elemenets and Isotopes that only the isotopes with a half-life greater than 0.5 Megaseconds or around a week. So in accordance with this I removed all unstable helium isotopes from the box. It is of course emphasized this applies to the infobox and not the overall article. The isotopes should be included in article but it was decided that having over 60 isotopes in an infobox would be not wanted. (Indium has more than 67 isotopes) Trace isotopes and those of human importance are also included in the infobox. --metta, The Sunborn 20:23, 18 Jun 2005 (UTC)

Ok, that's good with me, and thanks for letting me know. It might be an idea to put a note to the above effect in talk or in the edit summary, to stop lusers like me from reverting. Zeimusu | (Talk page) 13:33, 21 Jun 2005 (UTC)

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