Talk:Helium: Difference between revisions
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The last sentence of the first paragraph of [[Helium#Compounds]] says, "If confirmed by experiment such compounds will end helium's chemical nobility, and the only remaining noble element will be neon." This seems to be a strange thing to say. For one thing, as has been previously pointed out under "[[Talk:Helium#Funny stmt|Funny stmt]]", our experimental confirmation of helium compounds will not change helium's inertness itself—it will only modify whether we believe it is inert or not. Additionally, I don't know whether "nobility" is the right term here. We still refer to all of the group 18 elements as [[noble gas]]es, even though we know some of them form chemical compounds, right? I don't feel comfortable enough with my meager grasp of chemistry to change the sentence itself, so could someone address this, please? —[[User:Bkell|Bkell]] ([[User talk:Bkell|talk]]) 17:52, 28 February 2010 (UTC) |
The last sentence of the first paragraph of [[Helium#Compounds]] says, "If confirmed by experiment such compounds will end helium's chemical nobility, and the only remaining noble element will be neon." This seems to be a strange thing to say. For one thing, as has been previously pointed out under "[[Talk:Helium#Funny stmt|Funny stmt]]", our experimental confirmation of helium compounds will not change helium's inertness itself—it will only modify whether we believe it is inert or not. Additionally, I don't know whether "nobility" is the right term here. We still refer to all of the group 18 elements as [[noble gas]]es, even though we know some of them form chemical compounds, right? I don't feel comfortable enough with my meager grasp of chemistry to change the sentence itself, so could someone address this, please? —[[User:Bkell|Bkell]] ([[User talk:Bkell|talk]]) 17:52, 28 February 2010 (UTC) |
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:You are right. These used to be known as the "inert gasses." When scientists began forming compounds with them in the 1960s, "inert" was dropped, and the group became known as the "noble gasses," which does not mean that they cannot form compounds, only that it is difficult to do so. [[User:Plazak|Plazak]] ([[User talk:Plazak|talk]]) 18:00, 28 February 2010 (UTC) |
:You are right. These used to be known as the "inert gasses." When scientists began forming compounds with them in the 1960s, "inert" was dropped, and the group became known as the "noble gasses," which does not mean that they cannot form compounds, only that it is difficult to do so. [[User:Plazak|Plazak]] ([[User talk:Plazak|talk]]) 18:00, 28 February 2010 (UTC) |
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== How rare are helium burning stars? == |
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The article says that "only the very heaviest stars" produce helium ("at the very end of their lives"). Does anyone have the [[percentage]] of such stars? It's not like they are all 'blue supergiants', I have read that even [[Hertzprung-Russel diagram|type K]] will engage in some [[helium burning]], which includes nearly all of those stars that expired by now. But these really are less abundant than less massive stars. |
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Uses of Helium - diving
The section on the use of helium in diving is a bit misleading. Helium in itself does not protect against oxygen toxicity - reducing the amount of oxygen in the mix is what does that. You can achieve this by mixing helium with air and thus diluting the percentage oxygen in the mix, but there is nothing special about helium for this purpose. Helium also does not help reduce decompression time (at least for sports mixed-gas divers, I can't speak for military or commercial uses). Decompression theory is not an exact science, but many models will actually give a longer deco time if you replace nitrogen with helium. The key variable to deco timing is the percentage of oxygen in the mix (so when you reduce the oxygen percentage to avoid an oxygen tox, the trade-off is longer decompression times). The main reason for using helium in a deep diving mix is to reduce Nitrogen Narcosis. N.B. as well as the cost (helium is expensive) one of the problems of using Heliox as a dive gas is that it can affect your nervous system at depth (High Pressure Nervous Syndrome). For this reason, sports divers will normally stick with Trimix. —Preceding unsigned comment added by Rodgerclarke (talk • contribs) 09:59, 3 February 2008 (UTC)
- I'll fix the section so it's clear that any diluent gas can be used to protect against O2-tox. BTW, so called high pressure nervous syndrome is not a problem at most depths technical divers can reach (< 600 fsw). [1] Trimix is used in tech diving (almost all of which is done shallower than 600 ft!) not because of this, but because of cost. Plenty of very deep tech diving (300 to 500 fsw) has been done on straight heliox with no problem. Some (rich) divers prefer heliox because its lower density makes it easier to breathe (lower gas viscosity and density) at 10 to 20 atm. SBHarris 10:15, 3 February 2008 (UTC)
Spammers
This page is being recked by spammers - I think we should go back to a point before vandalism and then lock the page if possible. —Preceding unsigned comment added by Foxfoil (talk • contribs) 18:42, 5 February 2008 (UTC) What 'spammers' are you referring to? You're not being specific 24.184.234.24 (talk) 19:08, 29 May 2010 (UTC)LeucineZipper
Applications has a double negative
Because it is lighter than air, airships and balloons are inflated with helium for lift. In airships, helium is preferred over hydrogen because it is not inflammable and has 92.64% of the buoyancy (or lifting power) of the alternative hydrogen (see calculation.)
75.181.46.158 (talk) 01:43, 24 February 2008 (UTC)
- Inflammable is a bad word, because it means both "flammable" and "not flammable." For that reason, I discourage it ever being used. Let's just use flammable, which can't be misunderstood. SBHarris 02:02, 24 February 2008 (UTC)
- Concurred (I am the second of now three different editors to make that wording change with comparable edit-summary). DMacks (talk) 05:39, 24 February 2008 (UTC)
- Agreed. The word "flammable" is straightforward. The word "inflammable", particularly to a person whose first language is not English, looks as if it should mean the opposite. But it actually means the same. This can be confusing at best. Then to compound it further with a "not" prefix...well. "Not flammable" has a straightforward, unambiguous meaning to anyone, including those not fluent in the subtle inflections of English linguistic idiosyncracies. Feline Hymnic (talk) 09:45, 24 February 2008 (UTC)
- Concurred (I am the second of now three different editors to make that wording change with comparable edit-summary). DMacks (talk) 05:39, 24 February 2008 (UTC)
- Inflammable does not mean "not flammable"! The word "flammable" is a concession to those, who never bothered to find out the meaning of "inflammable". But as even Webster & Co. gave in, so be it. —Preceding unsigned comment added by Fak119 (talk • contribs) 10:03, 25 February 2008 (UTC)
- I agree. This is only one negative. inflammable is positive in that sense.--Stinkypie (talk) 14:51, 18 September 2008 (UTC)
The picture of helium (and other gases)
The picture of an empty vial in the infobox is IMHO not only useless but may lead to a false impression that helium forms a kind of a bubble in the vial. And it looks beige rather than colorless in the picture. These hold for pictures of other colorless gases, too. In my opinion these pictures should be removed ASAP. Regards, Michał Sobkowski (talk) 08:35, 16 March 2008 (UTC)
- The picture's inclusion is a residue of the systematic way minerals and elements are placed in collections for academic use. It conforms to a standard presentation, which, as you point out, is peculiar taken in isolation.
- It would be useful for there to be an image about helium that people could readily identify with. (The picture of a helium discharge tube seems like a step in this direction.) Failing that, there does seem to be some utility in a "seeing is believing" photo which shows, that, in observable fact, helium can't be seen. The alternative ... something along the lines of "helium can't be seen, so we aren't showing it" ... has the disadvantage that it distances a reader from an empirical observation that they could be reasonably expected to want to make for themselves.
- The photos in "Appearance" here and in hydrogen, kryton and neon however, are misleading, since a) they do not show any entity that is colorless, and b) have different colors. An empty test tube or bottle might work to better effect. An Appearance photo such as that in the oxygen article -- of liquid oxygen -- might be useful.
- A solution might be to use a pic of helium IN A DISCHARGE TUBE. Its bright yellow emission-line was observed in the Sun's corona during an eclipse, and was the reason for naming it after the sun (greek, "Helios"). SingingZombie (talk) 17:54, 26 December 2009 (UTC)
Amount of Helium left?
No mention in the article about the amount of helium left in the earth? I read in Wired that we had about a nine year supply at the rate we were using it currently, is this true? KiwiTallGuy (talk) 10:21, 15 April 2008 (UTC)
See the section on Natural Abundance, last paragraph. Chemist Lee Sobotka says (see reference cited) that the largest reserve in Texas has an eight-year supply at current rates, but there is more elsewhere. The reference also says that Sobotka believes that Russia will be the world's major source of helium in 30 years. Dirac66 (talk) 13:43, 15 April 2008 (UTC)
Liquid helium article
There is more information in this article on liquid helium than there is in the Liquid helium article which is little more than a stub. I would think either a merge into Helium of a split out into Liquid helium would be in order. SpinningSpark 19:09, 15 April 2008 (UTC)
- Strongly concur. I think merger into Helium is in order, given how little is in the Liquid helium page. Also, there is info about liquid helium scattered throughout the page here, so seems silly to extract or rewrite that well-integrated material just to fill out a stub-page. DMacks (talk) 20:53, 15 April 2008 (UTC)
language Use
Helium II state
Liquid helium below its lambda point begins to exhibit very unusual characteristics, in a state called helium II. Boiling of helium II is not possible due to its high thermal conductivity; heat input instead causes evaporation of the liquid directly to gas.
The correct term for this is Sublimation link http://en.wikipedia.org/wiki/Sublimation_%28chemistry%29 not evaperation —Preceding unsigned comment added by 67.58.208.247 (talk) 17:28, 2 May 2008 (UTC)
This is a little confused. In your second sentence, I would say that evaporation of liquid helium II IS boiling of helium II. And sublimation means direct conversion of a SOLID to gas, at least for most substances which have only one liquid state.
For helium it is true that direct evaporation of liquid helium II without passing through liquid helium I is ANALOGOUS to sublimation of ice (for example) without passing through liquid water. However before describing the HeII --> gas transition as sublimation in a Wiki article, I think we need a reference to a reputable physics paper or website which so describes it. Without a citation, this description would be "original research" which is against Wiki policy - see WP:NOR. Dirac66 (talk) 21:45, 2 May 2008 (UTC)
- How is an analogy "original research?" Inaccurate perhaps, but OR?! --Belg4mit (talk) 02:44, 4 May 2008 (UTC)
- Using a term in a way not used by the scientific community is OR in wikipedia terms as it is an invention. The OP was not proposing it as an analogy, he/she was proposing it as an actual meaning. SpinningSpark 02:57, 4 May 2008 (UTC)
speach on helium[all you need to know on helium]
Helium’s symbol on the periodic table is He. Its atomic number is 2 and its atomic weight is 4. It is the second lightest element after hydrogen. In its most common form, Helium 4, it has 2 Protons, Neutrons and electrons, though in its second and rare form, helium 3, it only contains one neutron. Helium has the lowest melting and boiling points of all elements being –272.2 C for the melting point and –268.93 C for the boiling point. Most of the time it is in it usual form, gas. Helium is colourless, odourless, tasteless, non-toxic, unreactive, 6 time lighter than the air we breath and part of the noble gas group of the periodic table.
Helium was first discovered by Pierre Janssen on the 18th of August 1868 when he came across a bright yellow line with a wavelength of 587.49nm[nanometers], in the spectrum of the chromosphere of the sun while observing an eclipse of the sun in India. Helium was then discovered by Joseph Lockyer on the 20th of October that same year while observing outer space. Lockyer concluded that it was caused by an unknown element, after unsuccessful testing to see if it were some new type of hydrogen.
Did you know that Helium was the first element discovered in space, before it was discovered on Earth? Also, I bet you didn’t know that Lockyer and an English chemist Edward Frankland, named the element after the Greek word for sun, Helios (written in Greek as it shows on the board). Most helium on earth is stored in the natural gas field in the US. In the modern universe almost all new helium is created as a result of the nuclear fusion in stars.
Helium is commonly used to change the pitch of a person’s voice however it is not a gas that is already in our body so it could be dangerous if too much is inhaled. One danger is as bad as death by asphyxiation (a condition of severely deficient supply of oxygen to the body) within minutes if breathing pure helium continuously. Helium is also used to inflate balloons and to make them rise to the roof or even further if released. These are common at special events, parties and celebrations. Helium is used for many other less common uses for example cryogenics (the study of very low temperatures), Deep-sea breathing gas, Cool superconducting magnets, Helium dating (a method of determining the age of a substance), Providing lift in airships such as blimps and all kinds of non-rigid airships, and as a protective gas for many industrial uses (eg. arc welding and growing silicon wafers) —Preceding unsigned comment added by Maddyson 961 (talk • contribs) 11:05, 20 May 2008 (UTC)
I don't see any specific information here that is not already covered in the Wikipedia article. Please clarify exactly what changes you want made. DMacks (talk) 14:31, 20 May 2008 (UTC)
Applications - breathing gas for deep diving
The last revision by User:Cryptic C62 was useful in bringing the references for high pressure nervous syndrome and the effect of easier breathing using heliox. However, these are concerns manifested principally below 150 m. The edit removed the mention of trimix which is the gas of choice for the 40 m to 150 m range. Since the majority of deep diving is in the latter range, we have lost the principal diving use of helium and substituted its use in exoteric scenarios that is really only of relevance in the field of extreme diving. In my humble opinion, it is also a mistake to take out the mention of "narcosis", since that is what it is known as (I've never heard a diver complaining that s/he had suffered from "pressure-induced neurological symptoms"). Perhaps one interpretation of WP:SPADE might be "Don't use over-technical language when plain language will do"?
As much as I dislike expanding a FA into topics it's not really about, I'll try to re-instate the use of helium in trimix to avoid nitrogen narcosis and do my best to leave in the HPNS. --RexxS (talk) 21:55, 27 June 2008 (UTC)
Uber-nice reference
I stumped onto this document that some of you might want to use to add a bit to the history section. Enjoy! Nergaal (talk) 15:25, 9 July 2008 (UTC)
Shouldnt it be
colour? —Preceding unsigned comment added by 77.99.186.110 (talk) 20:05, 10 July 2008 (UTC)
- I don't know what "it" you're talking about, but WP:ENGVAR might answer your question. DMacks (talk) 20:32, 10 July 2008 (UTC)
Effect of helium on voice
I am no expert on this and i am not debating the factual accuracy of it. In the applications section it says that it affects one's timbre but not pitch. But in the biological effect section it says that it changes the timbre in a high pitched way. How is this possible? Better let someone change it before it loses it's FA status. --Stinkypie (talk) 14:56, 18 September 2008 (UTC)
- Those statements appear to have been present during the various FA reviews, and both statements are specifically cited. Wikipedia is a tertiary source, so we can only report what others say. If they appear to contradict, well, then they contradict--that's an attribute of those sources, not our faithful reporting of them:) Please check those refs to figure out what specific technical meaning each is using here: do they mean "pitch" as the actual frequency or the perceived frequency? Ahh here we go: the bio section says "timbre in a way that makes it sound high-pitched" (emphasis mine), so that doesn't contradict a statement that the pitch actually doesn't change. DMacks (talk) 16:12, 18 September 2008 (UTC)
Helium gas has faster speed of sound than air, therefore as frequency is inversely proportional to the speed of sound – it is the frequency that will change. Therefore the pitch of the voice will change (to a higher pitch). 00:04, 13 August 2009 (UTC) —Preceding unsigned comment added by Yaniss2 (talk • contribs)
- I explain the vocal physics in more detail lower down on this TALK page, section entitled "Correction to Biological Effects". SingingZombie (talk) 16:23, 14 December 2009 (UTC)
Renewability
Should there be something mentioning its non-renewability? I'm no expert, but perhaps it deserves a mention somewhere, now we're in this environmentally conscious world. Greeny--210.50.186.57 (talk) 06:16, 27 October 2008 (UTC)
- Sounds like the "Occurrence and production" section would be the place. Interestingly, once He is released into the atmosphere, it's pretty much gone for good, but it is also constantly being generated inside the earth. So it's not really non-renewable in the same sense as crude oil or other mineable mineral deposits, just that we can't create it on demand like methane. DMacks (talk) 13:00, 27 October 2008 (UTC)
- If I've calculated correctly with the (2008) numbers in the article, current helium extraction is ~30,000t/year, so approximately 10 times the natural generation rate of 3,000 t.--Roentgenium111 (talk) 20:29, 25 February 2010 (UTC)
Hello, I wanted to bring attention to an article on the helium atom, which currently has few articles linking to it. I think it makes sense for something in this article to link to helium atom, but I wouldn't know where to insert this information. Thank you. LovesMacs (talk) 00:43, 14 November 2008 (UTC)
- More than fixed.SBHarris 01:30, 23 July 2009 (UTC)
Density of liquid helium
I believe that the density of Liquid Helium given in http://en.wikipedia.org/wiki/Helium is incorrect as 0.176 g / litre. To the best of my knowledge (and I buy the stuff by the kg), 1 litre of Liquid Helium has a mass of 0.125 kg.
Sincerely,
Andy Soper +27 82 56 27037 a.soper@ru.ac.za —Preceding unsigned comment added by 146.231.129.50 (talk) 14:47, 4 December 2008 (UTC)
- This site says 0.146 kg/L [2] at saturation pressure. The site in the liquid helium article says 0.125 g/mL. Clearly, unless there's that much difference in density due to pressure, we need an authoritative reference. SBHarris 03:44, 11 December 2008 (UTC)
Funny stmt
Compounds section says:
- These predictions may lead the collapse of helium's chemical nobility.
Are you sure? Or is the stmt simply and hillariously jumping between our mental image of the chemical properties and the chemical properties themselves? Or do we believe in magic and mind's control over matter? ... said: Rursus (bork²) 18:16, 18 January 2009 (UTC)
Big Bang
Am I incorrectly assuming that the Big Bang is still theoretical? I was unaware that Helium could indeed be produced by a theoretical model of the creation of the universe. I would assume there would be 100% evidence for the Big Bang being the correct model of creation of the universe before stating that Helium was produced in the Big Bang, instead of being theoretically produced in it. Can we get clarification for the reason this wording was chosen?
- Everything in science is theoretical, but some theories are better than others. If you are unaware that helium could be produced by a theoretical model of the creation of the universe, read Big Bang nucleosynthesis. Not only does simple application of the laws of physics predict that 6 to 7 protons will be made for every neutron in the Big Bang, but it predicts that when they all combine, as well as they can in the next five minutes (or so) that is all they have have before everything cools and expands too much for any more fusion, that the "ash" of the process will consist of about 24% by weight of helium-4, and 76% hydrogen. Which is just what we see in our own gas giants and the spectra of stars everywhere else in the universe. So that's impressive, inasmuch as the theory was not tinkered with to make it "come up with" the right answer on helium abundance. And yet it does. SBHarris 21:49, 5 May 2009 (UTC)
- First i must say this page is truly great,but as a physics prof. i must say that the individual is correct in saying we can not without some plausible doubt say that heliums mass creationwas caused by the big bang. There are to many opposing theories.I am now 62 years old and if it one thing i have learned is do not close the door on alternate theories. I would not have caught this but a student told me that wikipedia said that it was a fact. So please realize you are not only stating a theory(even if it is a great one)as a fact, but you are misleading many who read this.Ps I gave him an A on the paper and made him write another about the big bang and steady state theories —Preceding unsigned comment added by 68.115.131.180 (talk) 15:00, 17 June 2009 (UTC)
- If someone is going to pretend to be a professor, maybe they should remember how to write correctly? 24.21.10.30 (talk) 19:38, 24 August 2009 (UTC)
- Let's give people the benefit of the doubt. Talk pages don't exactly have high standards for grammar and few people in their 60s know how to type fast, let alone well. --mav (please help review urgent FAC and FARs) 01:13, 29 December 2009 (UTC)
- If someone is going to pretend to be a professor, maybe they should remember how to write correctly? 24.21.10.30 (talk) 19:38, 24 August 2009 (UTC)
- First i must say this page is truly great,but as a physics prof. i must say that the individual is correct in saying we can not without some plausible doubt say that heliums mass creationwas caused by the big bang. There are to many opposing theories.I am now 62 years old and if it one thing i have learned is do not close the door on alternate theories. I would not have caught this but a student told me that wikipedia said that it was a fact. So please realize you are not only stating a theory(even if it is a great one)as a fact, but you are misleading many who read this.Ps I gave him an A on the paper and made him write another about the big bang and steady state theories —Preceding unsigned comment added by 68.115.131.180 (talk) 15:00, 17 June 2009 (UTC)
Etymology
Is it worth mentioning in the article that helium got its anomalous -ium suffix because Lockyer and Frankland assumed that the new element would be a metal? The irksome thing is that, while I'm utterly sure that this is so, I can't find an unambiguous reference to cite - can any of you do better? Kay Dekker (talk) 23:02, 21 May 2009 (UTC)
Spelling error
In this article, the word "elegant" is misspelled "elligant".
- Thanks! Materialscientist (talk) 22:25, 6 July 2009 (UTC)
Would somebody please re-sprotect this page?
All the common element articles are excessively IP vandalized, and it's starting now again. SBHarris 18:45, 28 September 2009 (UTC)
Correction to Biological Effects
The explanation of the high pitch you get when you huff helium began by saying something very wrong: that the pitch of the voice is primarily determined by the dimensions of the resonant cavity, not by the stimulating frequency from the vocal folds. You can easily demonstrate how wrong this is by singing and sliding gradually from low pitch to high pitch, all on the same vowel. The resonance chamber from larynx to mouth plus buzz in the skull and sinuses changes only very little, but the pitch changes more than an octave and covers all the pitches between. That means if the cavity were determining pitch, you'd need to be gradually reducing its size for high notes to less than HALF the size for low notes! (For a trained singer with a two-octave range, to less than ONE QUARTER the low-note size.) No. In fact the vocal cavity, like the body of a stringed instrument, is a versatile resonator capable of supporting many frequencies, and what changes is the tension holding the vocal folds together, and the air pressure from below.
The reason the cavity can resonate at many frequencies without changing its dimensions (much) is, it's not like a trombone, which is a simple narrow cylinder, with length much greater than base-radius. The only available path for a sound wave through a trombone is directly from one end to the other, so the pitch is determined by the length, the wavelength of the sound being equal to the length of the cylinder, or an harmonic fraction thereof. In contrast, the voice is better-modelled as a WIDE cylinder, a can, with a pinhole in the center of the bottom, through which vibratory stimulation radiates into the can in all different directions. The path of the resonating wave through the vocal cavity can be direct from entrance to exit, as in a trombone, but it can also be crooked, ricocheting off the walls of the can. This makes many additional baseline resonant frequencies available, plus their harmonics, and the distribution of them--which of the possible vibrations actually occur, and how strongly--is determined primarily by the stimulating vibration, as in a stringed instrument, exactly opposite to what the article said.
Fortunately, I was able to correct this simply by deleting the misinformation, so I have not added any new reference to the article. However, if you want one, here it is: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2689615/ SingingZombie (talk) 10:33, 14 December 2009 (UTC)
- There's an argument over whether the pitch changes at all when you breathe helium. To me, it sounds as if it does. Several speech professionals claim it does not, precisely for the reasons you give (it's an oscillator-driven system not a resonator-driven one). Basically, even if you're breathing 80% helium, 20% oxygen, your vocal folds resonate at the same frequency, and all that changes is the timbre (strength of the various higher harmonics), not the fundamental pitch. Right now I'm sort of agnostic on the issue, not having had the time or the helium to do my own experiments. This article has said in the past that helium does and does NOT change the pitch of the voice. And you can find "explanations" that say both things on the net. If you're doing to go with your idea, you have to go whole hog with J. Wolfe's idea that timbre changes but pitch does NOT. See [3] SBHarris 03:23, 15 December 2009 (UTC)
- Wanna hear something even cooler? The vocal cavity is wide in the larynx up to behind the tongue, where it is narrow, and then it widens again in the mouth-and-sinuses. So it has a peanut-shape (or barbel-shape), just like the body of a guitar or violin! There must be something about the peanut-shape which confers extra resonances.
- By the way, I agree with you about the pitch/timbre ambiguity. That's one of the reasons I just deleted the misinfo but did not add new info. SingingZombie (talk) 17:20, 15 December 2009 (UTC)
- Note that J. Wolfe on the helium-singing article is the same guy on the article you cited. He's a wonk in the field. Wolfe and I had some correspondance in which I essentially said: "well, if the pitch doesn't change, how come everybody thinks it does, and why does it SOUND like it does? To which he essentially replied: "It doesn't sound like it does to ME, and here are the spectral analyses that show that the harmonics are separated by just the same interval on helium, which means that the fundamental (the pitch by definition, even if it's heard as a virtual pitch) is unchanged." So the harmonic power spectum of the voice (particularly amplitude of higher harmonics) is changed by helium, resulting in a major timbre change, but that's it.
We really have to do something about this on the Wikipedia, since if Wolfe is right, the article still remains wrong. Probably this topic deserves its own subarticle, there's so much confusion about it even in the cited literature. I've probably read about 3 different explanation of why helium changes voice pitch, but the biggest academic in the field claims it doesn't change it at all. Go figure. SBHarris 20:15, 15 December 2009 (UTC)
- I think the way the article reads now is fine--"...an increase in the pitch of the resonance frequencies..." Whether it's the overall pitch that changes or only the timbre, the pitches of the individual resonance modes certainly do change. If the pitch doesn't change (as Wolfe says) it's because the relative activities of the resonances also change to maintain the overall pitch, but not the timbre. The pitches of the individual modes--for instance, the shortest mode, straight up from larynx to mouth with no richochets--definitely does change its pitch, according to the change in the speed of sound. SingingZombie (talk) 06:47, 16 December 2009 (UTC)
- Note that J. Wolfe on the helium-singing article is the same guy on the article you cited. He's a wonk in the field. Wolfe and I had some correspondance in which I essentially said: "well, if the pitch doesn't change, how come everybody thinks it does, and why does it SOUND like it does? To which he essentially replied: "It doesn't sound like it does to ME, and here are the spectral analyses that show that the harmonics are separated by just the same interval on helium, which means that the fundamental (the pitch by definition, even if it's heard as a virtual pitch) is unchanged." So the harmonic power spectum of the voice (particularly amplitude of higher harmonics) is changed by helium, resulting in a major timbre change, but that's it.
Elemental mass
Correction to the opening paragraph of the main article: Helium is believed to make up 24 percent of the elemental (i.e., baryonic) mass of the universe (consisting of protons, neutrons, etc.), not the total mass. Most of the mass of the universe is currently believed to be non-baryonic, namely dark matter and dark energy. Compare the opening paragraph of the Wikipedia main article on "Hydrogen". —Preceding unsigned comment added by 76.90.2.195 (talk) 06:11, 25 January 2010 (UTC)
- I added "elemental" to the lead, but note also that it talks about our galaxy, not universe. Materialscientist (talk) 06:26, 25 January 2010 (UTC)
"End helium's chemical nobility"
The last sentence of the first paragraph of Helium#Compounds says, "If confirmed by experiment such compounds will end helium's chemical nobility, and the only remaining noble element will be neon." This seems to be a strange thing to say. For one thing, as has been previously pointed out under "Funny stmt", our experimental confirmation of helium compounds will not change helium's inertness itself—it will only modify whether we believe it is inert or not. Additionally, I don't know whether "nobility" is the right term here. We still refer to all of the group 18 elements as noble gases, even though we know some of them form chemical compounds, right? I don't feel comfortable enough with my meager grasp of chemistry to change the sentence itself, so could someone address this, please? —Bkell (talk) 17:52, 28 February 2010 (UTC)
- You are right. These used to be known as the "inert gasses." When scientists began forming compounds with them in the 1960s, "inert" was dropped, and the group became known as the "noble gasses," which does not mean that they cannot form compounds, only that it is difficult to do so. Plazak (talk) 18:00, 28 February 2010 (UTC)
How rare are helium burning stars?
The article says that "only the very heaviest stars" produce helium ("at the very end of their lives"). Does anyone have the percentage of such stars? It's not like they are all 'blue supergiants', I have read that even type K will engage in some helium burning, which includes nearly all of those stars that expired by now. But these really are less abundant than less massive stars.
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