Talk:Kelvin/Archive 1

"Water" != H2O
Isnt water meant to infer H2o is in a liquid form? Isnt steam meant to infer H2o being near a gasious form? isnt Ice meant to infer H2o being in state with near zero excitation to it? me thinks water should be replaced with H2o

Spelling
Is the Kelvin temperature scale actually supposed to be written as a lower-case k? I thought k stood for kilo- and K stood for Kelvins. --24.72.34.179 22:44, 14 Jun 2004 (UTC)

I think they meant that:
 * 1) A "kelvin" is written with a lowercase "k", just like "ampere" is written with a lowercase "a", even though it's named after a person too.
 * 2) However, the abbreviation for a kelvin is an uppercase "K", just like the abbreviation for an ampere is an uppercase "A".

200 K = 200 kelvins 200 A = 200 amperes

Perhaps the wording needs some clarification, or perhaps it's unnecessary. -- Curps 23:46, 14 Jun 2004 (UTC)

Page 31 of the United States National Institue of Standards and Technology (NIST) Special Puplication 811 (Guide for the Use of the International System of Units (SI)) states that unit names should be spelled out in full like any other English noun, with lower-case letters, except at the start of a sentence or in a title. However, if you write "degree Kelvin", Kelvin should be capitalized (since it's a type of degree, same way you'd write "Kennedy High School" and "high school") The publication actually uses celsius for the example but it's the same principle. A capital K should be used when abbreviating, since the unit is named after a person. -- Uberdog 02:14, 30 Jun 2004 (UTC)


 * According to the BIPM (see here), the "degree Kelvin" ceased to exist 36 years ago:
 * The 13th CGPM (1967-1968, Resolution 3) adopted the name kelvin (symbol K) instead of "degree Kelvin" (symbol °K) and defined the unit of thermodynamic temperature as follows (Resolution 4): ... 
 * On the other hand, Celsius has a capital C because it hasn't been adopted by the SI. -- Heron 08:25, 30 Jun 2004 (UTC)


 * No. Celsius has a capital C because it's one of the quirks of the English language (these are language-specific rules; it's different in German, for example, with all nouns capitalized) that the nouns naming units after people are not capitalized, but the proper adjectives identifying particular ones of ambiguous unit names are capitalized. Thus, when kelvins were called "degrees Kelvin" they also had a capital K, and the R is capitalized in degrees Rankine.


 * Furthermore, you are also wrong about degrees Celsius not being adopted by the CGPM. They are indeed part of the SI (which, as a system of measurement, cannot "adopt" anything), a derived unit with a special name.Gene Nygaard 13:39, 10 Dec 2004 (UTC)

In case anyone's interested, here's a NASA styleguide, which is where I confirmed my suspicion that a space belongs between the number and the symbol for Kelvins, unlike in many places in Wikipedia. NASA occasionally has trouble with units, but hopefully they can spell them right. -- Tantalate 01:47, 4 Aug 2004 (UTC)


 * I agree. The American NIST checklist mandates a space between every number and its unit.  The official SI brochure always uses a space (e.g. here), but I can't find an explicit statement on the BIPM site that a space is required. -- Heron 08:13, 4 Aug 2004 (UTC)


 * This topic comes up occasionally in other discussions. ISO 31-0 and the UK equivalent BS 5775 apparently recommend a space before the unit, but I have not seen the original text of either. I also find the recommendation in:
 * US NIST publication 811
 * US NIST checklist
 * UK NPL
 * IEE guide
 * misc.metric-system faq
 * The scope of the references certainly includes metric units. Whether the authors would recommend the same format for non-metric units is unclear to me. It may be implicit in the IEE reference and the unseen ISO and BS references. I would be surprised if any respectable author/editor would specifically want all copy to have spaces before metric units but not before imperial units. In summary, there are respectable references that say a space should be used and none that say a space should absent. Where each character is costly (such as on a cellular phone display), I don't think people worry too much if the space is absent, but Wikipedia pages have plenty of room for space characters.
 * Bobblewik 09:17, 7 Aug 2004 (UTC)

Any reason why both 273.16 ("...one kelvin is the fraction 1/273.16 of...") and 273.15 ("°C = K − 273.15") is used? which is the right one?


 * They are both right. 273.16 is the definition of the kelvin with respect to the triple point of water.  273.15 is the offset between the Celsius scale and the kelvin.  See the BIPM website. --Heron 14:18, 19 Oct 2004 (UTC)

What about the title of the article? Does it come under starting a sentence (therefore a capital) or should it start in lowercase to show that it is not capitalised at the middle of sentenses? I thought it should be lowercase, but that was removed and aparently this has been discussed before. Daniel 23:43, 29 January 2006 (UTC)


 * Yes, it has been discussed before. See "Technical Limitations" further down this page. The point is that if you're going to put that lowercase warning at the start of this article, then you need to add it to every other article whose name is a common noun, from aardvark to zymurgy. There is nothing special about SI unit names. They are not like those pretentious trademarks that are supposed never to be capitalised. The SI people (BIPM) could have saved us a lot of trouble by saying "spell unit names as common nouns, even if they are named after somebody", but instead they cocked up and wrote the incomplete instruction "do not capitalise, except at the start of a sentence", thus leaving certain cases, like article titles, undefined. We should use our common sense and use the simpler "common noun" rule unless somebody tells us clearly otherwise. --Heron 13:21, 30 January 2006 (UTC)

Definition and comparison with Celsius
I just had an edit of mine reverted and I'd like to explain myself. The BIPM brochure on kelvin, which link I added to the article, states the following (emphasis is in the original):


 * The 13th CGPM (1967-1968, Resolution 3) adopted the name kelvin (symbol K) instead of "degree Kelvin" (symbol °K) and defined the unit of thermodynamic temperature as follows (Resolution 4):


 * The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.


 * Because of the way temperature scales used to be defined, it remains common practice to express a thermodynamic temperature, symbol T, in terms of its difference from the reference temperature T0 = 273.15 K, the ice point. This temperature difference is called the Celsius temperature, symbol t, and is defined by the quantity equation


 * $$t = T - T_0$$

I re-stated and summarized this as follows:


 * The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. It is defined as the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. A temperature given in kelvins, without further qualification, is measured with respect to absolute zero, where molecular motion stops. It is also common to give a temperature (a so-called Celsius temperature) relative to the reference temperature of 273.15 K, approximately the melting point of water under ordinary conditions.

I think this is a fairly faithful rendering of the BIPM's description, but I'm open to discussion on the point. Our prior (and, after the revert, our current) definition reads as follows:


 * The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. It is defined by two facts: zero kelvins is absolute zero (when molecular motion stops), and one kelvin is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. The Celsius temperature scale is now defined in terms of the kelvin, with 0 °C corresponding to 273.15 kelvins, approximately the melting point of water under ordinary conditions.

The problem with this description is that it does not make any distinction between the kelvin unit of temperature versus the Kelvin thermodynamic temperature scale, which measures temperature relative to absolute zero. For example, take the statement that "zero kelvins is absolute zero". Consider the question: what temperature change is necessary in water at standard temperature and pressure in order to liquefy it? The answer is "zero kelvins", but this most certainly does not indicate that the liquefied water would be at absolute zero.

My version of the definition used terms and phrases introduced by the BIPM brochure:


 * 1) a kelvin is 1/273.16 of the thermodynamic temperature of the triple point of water,
 * 2) it is common to measure relative to 273.15 kelvins, and
 * 3) such practice is referred to as "Celsius temperature".

It also includes some embellishments I thought were fairly benign (and were pre-existing):


 * absolute zero is where (not "when") molecular motion stops, and
 * 273.15 kelvins is approximately the melting point of water.

All in all, I think this is a fairly uncontrovercial definition of the kelvin, and I'd like to reinstate it, or something like it. --Doradus 03:30, Dec 30, 2004 (UTC)


 * No objections in almost 9 months; I have restored my paragraph with a slight modification to avoid the phrase "so-called Celcius scale". --Doradus 16:38, September 7, 2005 (UTC)

Dispute - Definition of Kelvin
When I look this up, there seems to be a descrepency between the definition of absolute zero with Zero Kelvin and what is provided by my Physics professor and my physics textbook. Here, it says ..."is measured with respect to absolute zero, where molecular motion stops (except for the residual quantum mechanical zero-point energy)." However, my physics professor and my textbook explicitly disagrees with that exact definition and the textbook says (emphasis mine): "Absolute zero is not the temperature at which all molecular motion ceases."

As such, the book continues to describe it as: "One way to determine absolute zero is to graph the pressure of a fixed volume of gas as a function of temperature." So the book graphs the temperature of several gases' pressure as temperature drops, and they after many readings, you can then continue to "extrapolate the linear relationship, as described by the Ideal Gas Law." This results in a point in which this converges to a point called absolute zero. My textbook describes it as: "The absolute zero of temperature can also be described as that temperature at which all of the energy that can be removed from the object has been removed."

The textbook I used is: "The World of Physics: Mysteries Magic & Myth" by Dr. John W. Jewett, Jr., Published by: Harcourt College Publishters. ISBN 0-03-031944-7. If someone can verify/support this (or disprove it) with other sources, it would be appreciated. -- Akosygin 22:43, 23 January 2006 (UTC)


 * I don't understand your point. The article only makes a qualified statement with respect to molecular motion, just as your textbook does.  Only difference is, your textbook doesn't spell it out as much. The "can be" vs. "has been" is just a different way of explaining the zero state energy zero-point energy explained at that link in the definition here, isn't it? Gene Nygaard 01:13, 24 January 2006 (UTC) fixed link Gene Nygaard 01:28, 24 January 2006 (UTC)


 * Well, the article makes the exact statement in which the textbook specifically says it is not. "absolute zero, where molecular motion stops" is exactly the definition as stated by the textbook of what absolute zero is not. It specifically states that is not what it is, and yet the article says in a way that molecular motion stops. Therefore, it is rather contradictory to say that the article AND the textbook is correct when they are opposite statements. That is why I am requested either: A.) A rewording of the statement in the article; or B.) support for, or disprove, of what my textbook has said what absolute zero is specifically not. -- Akosygin 01:18, 24 January 2006 (UTC)


 * It is only a qualified statement. Sure, try to reword it if you like.  But this isn't an "accuracy dispute".  Your textbook's statement is at least as misleading, if not more so.  Remove those templates.  BTW, I fixed the link in my earlier reply above, so it's not a redlink but the one in the article.Gene Nygaard 01:28, 24 January 2006 (UTC)


 * Before I take up on your offer to reword it, let me find additional support for this so that I may more appropriately provide the new wording. If anyone else has additional support either way, help in sheding some light in to this would be appreciated. -- Akosygin 04:24, 24 January 2006 (UTC)

"Technical limitations"
Is the "technical limitations" note necessary? "Kelvin" is capitalized at the start of a sentence or in a title, just like cat, washing machine, or any other common noun. The page follows Wikipedia's capitalization convention; what's wrong with that? --tilde 00:21, September 7, 2005 (UTC)
 * Hmm, yeah, I guess you're right, it really isn't any different from any other noun, I just figured since it is never referred to as Kelvin anymore, but that's really true of anything -- MacAddct1984 23:08, September 7, 2005 (UTC)

Kelvins v. kelvin?
Which is it? I thought this unit was always said in the singular. That is, "0 kelvin", "10 kelvin", "a difference of 42 kelvin", "measured in kelvin", and never "kelvins". Is that right? —BenFrantzDale 22:32, 9 October 2005 (UTC)


 * No. Gene Nygaard 22:52, 9 October 2005 (UTC)


 * I think this is a habit ingrained from the "degrees kelvin" days. It's not the norm any more.  --Doradus 03:13, 10 October 2005 (UTC)


 * Yes, that's what I would have said if I'd had more time. In the old days before the name was changed, the K was capitalized because it was an adjective, modifying the noun degrees, and that's just a quirk of English usage that we do it that way.  But also, the "s" was then added to degrees, the noun part, and the adjective "Kelvin" didn't change in the plural when we had degrees Kelvin.  But now the kelvins are the noun, and they take the normal plural, and are written with a lowercase k just like volts and watts and amperes and newtons and joules.
 * Lot's Lots of people haven't figured that out, of course—they probably didn't pay much attention in English class to little nuances like parts of speech—so you do often see things like 298 Kelvin or 298 kelvin. But the keepers of our standards realize what's going on, and add the normal "s" in the plural of the spelled out word.  Gene Nygaard 04:38, 10 October 2005 (UTC)
 * I did pay attention in English (and I do appreciate your use of em dashes), but from my science and engineering studies, "kelvins" just sounds wrong. I'd be interested in seeing a reference that says that's correct if you have one. (Either way, I think Doradus is dead on in terms of etimology.) —BenFrantzDale 20:27, 20 October 2005 (UTC)


 * Rule in NIST SP811 section 9.2 (kelvins not listed among exceptions)
 * "Plural unit names are used when they are required by the rules of English grammar. They are normally formed regularly, for example, "henries" is the plural of henry. According to Ref. [8], the following plurals are irregular: Singular - lux, hertz, siemens; Plural - lux, hertz, siemens. (See also Sec. 9.7.)"
 * Usage in BIPM SI brochure section 2.1.1.5
 * "A difference or interval of temperature may be expressed in kelvins or in degrees Celsius (13th CGPM, 1967-1968, Resolution 3)."
 * Gene Nygaard 21:23, 20 October 2005 (UTC)


 * It is interesting to note that in the paragraph where Gene Nygaard rails against people for not paying attention in English class the first word has been misspelt. There shouldn't be an apostrophe in "Lots". A case of the pot calling the kettle black I think. Pedro20 03:34, 9 November 2005 (UTC)


 * I don't spell lots with an apostrophe; thanks for calling it to my attention. It is a typo, a miscommunication between my brain and my fingers, something I find happening more often all the time. I will correct it, just as I do when the s is missing in the plural of kelvins (but it's usually only my own mistakes that I will change on a talk page). (signed later, Gene Nygaard 08:31, 9 November 2005 (UTC))


 * I work in the Aerospace industry in the UK, but have frequent dealings with US parts of the industry. In the UK the plural is 'kelvin', however the US (which, as we all know, hasn't used English for nearly two and a half centuries ;-) ) uses 'kelvins'.


 * Well, the scientific community elsewhere in the world says "kelvins" when speaking English, so it would seem that the Americans are the ones speaking correct English afterall. I certainly wouldn't go to the store and ask for a dozen banana.


 * No, but you might ask for a dozen sheep, a dozen trout, or a dozen salmon - to name but a few :)

Temperature and energy
How can Kelvin be converted into electron volt, let alone with a dimensionless conversion factor as in this article? Temperature and energy are different physical properties. Kelvin is a base unit and $$eV=1.602*10^{-19}J=1.602*10^{-19}kg*m^2/s^2$$. --Hardy 21:46, 16 October 2005 (UTC)
 * That looks like its the average energy per atom, which may or may not be correct, but either way it is certainly true that temperature is not energy and any exposition of the above formula should make that clear. &mdash;BenFrantzDale 20:22, 20 October 2005 (UTC)
 * I agree. According to my physics book ("Gerthsen Kneser Vogel: Physik") and sources in the WWW the average kinetic energy of particles of an ideal gas is

\overline{\mathrm{E_{kin}}} = \frac{3}{2} \cdot k_B \cdot \mathrm{T} $$.
 * So even the constant of proportionality is incorrect. I wonder were these formulae came from originally. --Hardy 10:16, 22 October 2005 (UTC)
 * Shouldn't that be

\overline{\mathrm{E_{kin}}} = \frac{f}{2} \cdot k_B \cdot \mathrm{T} $$.
 * Where f is the number of degrees of freedom? &mdash; Sverdrup 10:52, 29 October 2005 (UTC)


 * That is right, but for ideal gases f is 3. So the formula applies to ideal gases and approximately to ::::monoatomic gases as He. For gases whose molecules consist of two atoms as O2 f is 5. For molecules with more than two atoms that are not on a straight line f is 6. Anyway imho the section "Temperature and energy" is not relevant for this article and should be removed. Otherwise we could add still more relations between temperature and energy as energy per water molecule or per iron atom. --Hardy 18:51, 30 October 2005 (UTC)

So do you guys have the rigth formula? Looks kinda silly, a disputed tag on a formula... --The Minister of War 17:01, 24 November 2005 (UTC)

"Why the overline?"
 * The overline stands for average. Not all particles have the same kinetic energy at the same temperature of the gas but the average energy of the particles is proportional to the temperature (see Maxwell-Boltzmann distribution). A single particle has no temperature but a kinetic energy. So it does not make sense to refer to a (single) molecule. --Hardy 14:34, 3 December 2005 (UTC)

I arrived at this talk page ready to complain that the "Temperature and energy" section (version as of now) is irrelevant and should be removed. Seeing that Hardy already made this complaint months ago, I'm removing it. Melchoir 11:32, 25 February 2006 (UTC)


 * From my reading of Hardy's comments and edits, I thought he was objecting to the kelvin/eV conversion. I initially thought you were talking about that too, because I added it back in a few days ago. (Regardless, I agree the section you removed was irrelevant.) - mako 12:11, 25 February 2006 (UTC)
 * You cannot convert directly from electronvolts to degrees kelvin. A gram of water 100 kelvin will have 418 joules of heat energy.  A gram of gold at 100 kelvin will have 12.9 joules.  See specific heat capacity for more information.  The ratio of temperature to energy depends on mass and chemical structure, and the constant of proportionality is not absolute. —The preceding unsigned comment was added by 68.49.149.206 (talk • contribs) 07:29, 19 June 2006  (UTC)
 * The table links directly to Electronvolt, which explains this very issue.
 * Please be aware that when dealing with questions of abstract formalism, any sentence that starts with "You cannot" is almost guaranteed to be wrong by the time you finish it! We can't convert from electronvolts to degrees kelvin? Then how come we just did? Whether the conversion is physically meaningful is a separate matter; it so happens that it is, just not in terms of heat capacity. Melchoir 09:49, 19 June 2006 (UTC)


 * An ELECTRON VOLT (eV) is the kinetic energy gained by an electron [or any other particle with the same size charge] when it is accelerated through a one volt (1 V) electric potential. Moving a charge of 1 C through a potential of 1 V takes 1 J of work (and will produce 1 J of kinetic energy)


 * 1 eV = 1.60217733 x 10E-19 joules


 * An electron has a negative charge of 1.60217733 x 10E-19 coulomb (abbreviated C).
 * A proton has a positive charge of 1.60217733 x 10E-19 coulomb (abbreviated C).


 * This from the Wikipedia article on the Boltzmann constant:
 * The Boltzmann constant (k or kB) is the physical constant relating temperature to energy.


 * It is named after the Austrian physicist Ludwig Boltzmann, who made important :contributions to the theory of ::::statistical mechanics, in which this constant plays a :crucial role. Its experimentally determined value ::::(in SI units, 2002 CODATA value) is:


 * k = 1.3806505(24)×10E−23 joules/kelvin


 * = 8.617339×10E−5 electron-volts/kelvin.


 * You can easily show for yourself that 1 eV is equivalent to a temperature of 11,604 kelvin.


 * After all temperature is really only a measure of kinetic energy, whether it be one proton - basically a ::::hydrogen gas consisting of only one atom - or billions and billions of hydrogen molecules in a balloon. It's ::::just more convenient to use electron-volts for the very small and temperature for larger objects, which don't ::::appear to be moving. --154.20.29.147 04:29, 24 June 2006 (UTC)TwoCents

The "conversion" between kelvin and electronvolts still does not make sense because these are differenz units as stated above ($$eV=1.602*10^{-19}J=1.602*10^{-19}kg*m^2/s^2$$). An IP user wrote months ago "they are not compatible". Otherwise we could further convert eV into grams using the equation E=m*c². It may be true that eV is used as equivalent for K in certain contexts but that is no conversion as from °C to K etc. "1 eV is equivalent to a temperature of 11,604 kelvin" is not the same as "1 eV = 11,604 kelvin". --Hardy 19:24, 16 August 2006 (UTC)

Terminology
The symbol '°' is used when refering to a specific temperature (except for the absolute scale when the unit is used directly without any further symbol). However when refering to the temperature interval, the term 'deg' is used to avoid confusion.

Thus 1 deg Celcius = 1 deg Kelvin. But 1 °Celcius <> 1 Kelvin.


 * Nonsense. Why in the world should we believe someone who doesn't know how to spell Celsius and who doesn't know, even after editing (almost slipped up and said reading, but obviously that didn't happen) this article, that "degrees Kelvin" were thrown out nearly 40 years ago?


 * There is of course, a grain of truth behind this notion—it may have been the recommendation for a brief period, only a few years. But that silliness was specifically disavowed by the CGPM in 1967, at the same time the degrees Kelvin were abolished.  Gene Nygaard 00:01, 10 March 2006 (UTC)


 * Furthermore, the degree symbol should only be used for temperatures with a letter symbol identifying the scale, not with the spelled out word, and kelvins are not capitalized, if you are really interested in following the rules. Gene Nygaard 00:05, 10 March 2006 (UTC)

Capitalization explanation
I made some changes in the convoluted explanations which included "Notwithstanding the naming convention historically used for the other temperature scales, SI unit names are never capitalized."

One of the biggest problems, of course, with this explanation is that the "degree Celsius" is an SI unit, a "derived unit with a special name", listed in "Table 3 SI derived units with special names and symbols" in the BIPM's SI brochure, for example.

The change isn't due to some inherent difference between kelvins and various other kinds of degrees. It remains "degrees Celsius". Furthermore, though the CGPM doesn't concern itself with the non-metric units, it also remains not only "degrees Fahrenheit" but also "degrees Rankine" in the other absolute temperature scale. Gene Nygaard 12:42, 14 June 2006 (UTC)


 * Furthermore, "degree Kelvin" was the name of the SI unit for over seven years after the SI was introduced in 1960. So it has nothing to do with "SI unit names are never capitalized". Gene Nygaard 13:29, 14 June 2006 (UTC)


 * Note also that the SI rules generally deal mostly with the internationally uniform symbols, and that the spelled-out versions are not subject of uniform, worldwide rules, but rather their spelling and usage is language-specific. In German, for example, it the unit is now the "Kelvin" with a capitalized K as with other nouns in German, unchanged in plural as other measurements such as "2,5 Meter"  and remain unchanged in the plural in the German language.  Gene Nygaard 14:09, 14 June 2006 (UTC)

Scientific papers using a mix of °C and K
Citations are not required for obvious observations. Just look at scientific papers or technical articles on precision temperature measurement instrumentation. Check out the first paragraph of this article on SPRDTs 304 KB PDF. The scientific world abounds with this mixed use. It's hard to find a rational explanation for why this practice exists and a Wikipedia article on the kelvin is the perfect location for it. An article in Wikipedia can give the explanation that the BIPM's rule officially allowing the °C to be used to express an increment should have settled the issue and the scientific world is retarded (but I doubt that is a very satisfactory way of addressing the issue). Greg L 19:33, 14 June 2006 (UTC)


 * This mixture of degrees Celsius and kelvins may not need a citation&mdash;if specific reasons for it aren't spelled out. If reasons are given, we need something more than your personal speculation as to those reasons (it is fine with me if you express those speculations in the talk page discussion, but they don't belong in the article itself unless you can find some backing for them).  However, it is also the specific claim not that this usage exists but that it is "widespread" as has been stated in this article is what might need a citation in that case.  Maybe it just needs rewording so as not to express it in a way that makes it look like a rule that is regularly followed, rather than a specific citatation in this case.


 * Of course, an alternative explanation, different from the one which you gave in this article, for the usage in the pdf file you cite above, is simply the avoidance of the use of a prefix with degrees Celsius and its symbol, as a major reason behind the use of "mK" rather than the numerically equivalent "m°C" in this case. Some people may find that "m°C" symbol ugly, even if some sources (NIST SP811 is the one I have seen addressing it) say that this is an acceptable combination. I suspect that the "mixture" is less likely to happen in any context when prefixes are not used.


 * However, a specific claim of different rules for the plurals is a different story. That is the one that really needs a citation.  If you are going to claim a rule, you need a citation to that effect.


 * This is a rule I have never seen stated anywhere other than this article. Can you show otherwise, by providing a specific citation to a reliable published source stating the rule as you have stated it here?


 * Note that neither Merriam-Webster's 11th Collegiate nor NIST's SP811 recognize any use of "kelvin" as a plural of "kelvin". Nor do any of a half-dozen or so other sources which I have seen specifically addressing the issue of the plural.  So even if you do find such a specific example stated, the most you would have is a conflict in the rules as put forth in various sources, not something you can state as a flat-out rule.


 * Original research won't do for that purpose. What you need is a citation for the claim that "Note however, that when referring to a particular temperature on the kelvin scale, the singular form for kelvin (no “s” at the end) is used; when referring to uncertainties and differentials, the plural form is used."


 * Then, if such a rule is actually stated anywhere, we can look at how often that rule is followed, versus how often other rules are followed in this context. We can then consider how much say-so the proponent of the rule really has in issues such as this.


 * Can you even show me any published sources (at least not published by you) which do both of the following?
 * use "kelvins" for plurals for intervals, and
 * use "kelvin" for plurals for readings.


 * I've never seen any article whatsoever following that rule. It appears to be a figment of your imagination.  Furthermore, it needs to be considered in the context of the specific language of the resolution of the 13th CGPM, specifically asserting that it is the same unit in either case, and that it should have the same name and use the same symbols in both cases.  Not different symbols such as "°K" for readings and "deg K" for intervals (which may have been recommended by someone, perhaps even the CGPM, at some earlier time), and not different grammar rules for the usage of the words.  Gene Nygaard 20:48, 14 June 2006 (UTC)

The imporant issue in science papers is the unambiguous communication of temperature values and uncertainties. See this NASA link which referrs to "An average liner metal temperature of 915 K, 355 kelvins greater than…" This is common practice in real-world science that is observed for a very good reason: it avoids confusion. The reasons underlying this practice should be explained even if it isn't sanctified by an international body. The very heading of this section ("Why technical articles use a mix of kelvin and Celsius scales") betrays its reason for existence: to simply explain why it is done this way. This is a community resource and you are free to contribute to this article. I hope you can make this section interesting, truthfull, and informative. If you think the whole section should be deleted, I can't stop you and don't have time to play "musical reverts" Greg L 22:53, 14 June 2006 (UTC)


 * Your example here has nothing to do with your fictional plurals rule. Gene Nygaard 03:14, 15 June 2006 (UTC)


 * It doesn't have anything to do with mixing degrees Celsius and kelvins either; both the temperature reading and the interval are expressed in kelvins in this case. Gene Nygaard 03:16, 15 June 2006 (UTC)


 * Now it is your turn to explain other NASA usage, such as:


 * : "In the first report, 150 kelvins was achieved in a one stage cooler and 120 kelvins in a two stage device."


 * : "from near-surface pockets of liquid water at temperatures of 273 kelvins (0 degrees Celsius)"


 * : "0 kelvins" and a temperature scale showing colors corresponding to a range of temperature readings from 2.7249 kelvins to 2.7251 kelvins.


 * Gene Nygaard 03:28, 15 June 2006 (UTC)

Have you considered asking a Ph.D. chemist about the mixed use of °C and kelvins in scientific papers? Greg L 03:54, 15 June 2006 (UTC)


 * Gene, Here #6,127,915 is a patent on a high temperature platinum resistance thermometer. You can see that they use °C for temperatures and mK for tolerances.  Admittedly, they use °C for tolerances too.  Still, it illustrates the practice (particularly in the temperature measurement world where the practitioners of this art tend to be rigorous with their temperature terminology) of the mixed use of °C for the tolerance and mK for the uncertainty. Greg L 04:05, 19 June 2006 (UTC)

multiples
Please don't remove multiples, for consistency they are in all seven base SI units.

PLEASE GIVE THE HIGH VOLTAGE BETWEEN LOW VOLTAGE

mentioning namesake earlier
I think this unit being named after Baron Kelvin should be mentioned earlier than it is now, perhaps even in the first sentence as it is with Celsius. I think finding out who a unit is named after is often important to readers. What do others think? --Allen 06:19, 12 September 2006 (UTC)


 * No response; I made the change. I also removed the reference to the River Kelvin; that's more relevant to the article on the person, where it's already mentioned.  --Allen 02:15, 20 September 2006 (UTC)