This site uses cookies. Some of these cookies are essential to the operation of the site, while others help to improve your experience by providing insights into how the site is being used. For more information, please see the ProZ.com privacy policy.
Cookie settings
point of a sentence
W+O/S+C
Apr 15, 2016 23:29
8 yrs ago
3 viewers *
English term

kelvins / Kelvin

English Tech/Engineering Science (general) Temperature
OK, in my little world we have degrees Fahrenheit, degrees Celsius and Kelvin for expressing temperature.

Has anyone come across 'kelvins' with lowercase K plus 's'? I'm talking about in an English-language textbook for A-level or university-level physics/chemistry.... ?

It was new to me, but google suggests it's not uncommon.

I've such a textbook to edit, and am wondering if changing the kelvins would be overcooking it.

Any reputable textbooks using 'kelvins'?
Anyone?

Nice weekend,
Cilian
Responses
4 +3 kelvins or K

Discussion

Björn Vrooman Apr 19, 2016:
@Charles At least my comments about Celsius were not to be taken seriously. The other matters - hyphenation, non-breaking space, and upper- or lowercase - were.

Both the UK and the US Metric Association are not official government institutions. NIST, however, is. There is more than just one UK government document refusing to acknowledge a kelvin plural (the one I referenced is called "Writing for Home Office Science"). The same is true for hyphenation where the BBC, UK and US official sources and the Guardian Style Guide can't seem to agree, really. I haven't looked through EU sources again, so I am not sure whether it has something to do with that, but as far as I recall, official SI unit documents are not necessarily in line with UK usage.
Charles Davis Apr 19, 2016:
degrees Celsius Are the Brits more prone to be a law unto themselves on such matters? Perhaps we are. The BBC certainly is on this. If they say 30 Celsius as a matter of policy it simply means that they've decided to use an ellipsis and omit the word "degrees". Nothing wrong with that; people do it quite often, but it's hardly a normative rule for anybody else. The unit is a degree Celsius. There is no unit called a "Celsius" and there is not likely to be in the future; there's no call for it. If there were, it would be spelt with a lower-case c (celsius). Whether the plural would be celsiuses or celsius (cf. siemens) is an intriguing point but is (fortunately) not worth debating.
Björn Vrooman Apr 19, 2016:
@Tony
Thank you for the info. If I understand it right, he didn't use a plural though?

@Cilian
Thanks, Cilian. It was quite an interesting discussion to read through. I also see now why you asked for textbook examples :)

Now take those two...
http://www.proz.com/kudoz/English/linguistics/6083285-100_m2...
http://www.proz.com/kudoz/german_to_english/medical_pharmace...

...and you get a really good mash-up - or chaotic result may be more like it.

It is an unproven hypothesis, but it seems to me that based on all these discussions, the US seems to have a more straightforward answer to SI unit names and layout - after all, the Department of Commerce is directly involved here. In the UK, there seem to exist many different opinions (see also the gov.uk document I found.)
Cilian O'Tuama (asker) Apr 18, 2016:
Found it, if anyone's interested. http://www.proz.com/kudoz/5370958
Cilian O'Tuama (asker) Apr 18, 2016:
Wasn't there a similar discussion a few years ago? Not about kelvins, but about spaces and degree symbol ° and Celsius/Fahrenheit/Kelvin? I seem to remember Tony mentioning the BBC weatherman there too. In fact, I'll see if I can find it. Just out of interest. Strange the things you remember. :-)
Tony M Apr 18, 2016:
@ Björn Not sure; I remember the BBC weatherman telling us the from now on temperature would be expressed in Celsius, and explaining that there were no degrees; I'm pretty sure I saw this on UK TV before I left the UK? i.e. prior to '96
Björn Vrooman Apr 18, 2016:
@Tony Was that before my time (as akward as it may sound - you can discount everything before, say, the 1990s)?

I still know centigrade and I see some mentioning of "celsiuses" online, but not sure whether to trust that at all.
Björn Vrooman Apr 18, 2016:
Sorry for the late reply. I have entered the answer and hope that I have sufficiently incorporated most of the statements made here.

@B D Finch
I don't like Wiki as a reference - my university professors wouldn't accept anything like it. I quoted Oxford instead to corroborate your usage of "Kelvin scale."

On a side note:
There is one non-SI unit where you can threaten me all you want, I will continue using the singular form, albeit dictionaries may recommend a plural: bar.

Every time I read pressure and "100 bars" somewhere, the first thing that pops into my head is: of gold? chocolate?
Cilian O'Tuama (asker) Apr 17, 2016:
Thanks everyone... for your time, thoughts, insight. I think I can safely leave the kelvins. I just couldn't recall ever seeing it written that way in a textbook, hence the Q. THanks again.
Charles Davis Apr 17, 2016:
Sorry, but not N degrees Kelvin You can't say that any more in a scientific text. Just N kelvins.
B D Finch Apr 17, 2016:
Wikipedia should get a mention https://en.wikipedia.org/wiki/Kelvin
"The kelvin is a unit of measure for temperature based upon an absolute scale. It is one of the seven base units in the International System of Units (SI) and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, ..."

Note their careful use of lowercase "k" for the unit of measurement and upper case for the "Kelvin scale". The unit of measurement must, as others have noted, be able to have a plural. So, you will have to check that the plural and lowercase are used in the correct contexts. Temperature may rise or fall by N kelvins or by N degrees Kelvin.
Neil Ashby Apr 17, 2016:
I looked in my Kotz & Treichel handed out by BP at the start of my undergrad course (1996) and it uses "kelvins".
Charles Davis Apr 17, 2016:
And if people want evidence of the use of these books they can simply search for "Krane" "physics" "reading list", for example (in this case the first results include Balliol Oxford, Queen Mary London, Salford, Edinburgh..., not to mention Princeton).
Charles Davis Apr 17, 2016:
Björn Of course!

Krane's book is available here:
https://fisluisabraham.files.wordpress.com/2014/08/krane-k-m...

And Young and Freeman is here, and can be downloaded in pdf to do a search:
https://docs.google.com/file/d/0B_FOFMzF0_0gbjNxakkzUkV4dzg/...
Björn Vrooman Apr 16, 2016:
@Charles May I incorporate your references into my answer? I will point to the discussion box, but I know how people hate reading through all those entries usually.
Charles Davis Apr 16, 2016:
Another example Hugh D. Young & Roger A. Freeman, University Physics: With Modern Physics, 13th ed. (Addison Wesley), nearly 1600 pp, seems to be widely used in British universities. It has "kelvins".
Björn Vrooman Apr 16, 2016:
@Charles I suppose I did, thank you. We have a very late dinner today, I'll post it afterwards.
Charles Davis Apr 16, 2016:
By the way, Björn, would you care to answer the question? You did quite a lot of work on it before the rest of us arrived.
Charles Davis Apr 16, 2016:
@Björn I take your point, though I think the question of what is correct, as well as what is customary, is relevant. It would be quite a task to track down all the Physics textbooks used in UK universities and check them, since they are often not available online. But for example Kenneth Krane's Modern Physics, 3rd ed. (Wiley) which is on some UK university reading lists, uses "kelvins".

But my point is really that Cilian has to decide whether to change kelvins to kelvin in a text he is editing. And I say that kelvins is demonstrably and indisputably correct and that there are therefore no grounds for changing it. This is so, in my view, regardless of what other textbooks use, though as a matter of fact the ones we've looked at do seem to use kelvins. A more difficult decision would be whether to change kelvin to kelvins, because it depends on whether you think an incorrect form that is nevertheless widely used by professionals (and sanctioned by CERN, no less) should be corrected or left alone.

By the way, "degrees Kelvin" became effectively obsolete in 1968, when the name kelvin was adopted for the unit of thermodynamic temperature:
http://www.bipm.org/en/CGPM/db/13/4/
Björn Vrooman Apr 16, 2016:
PS Would Pearson Education be acceptable as a reference? I know they are used in certain US universities.
Björn Vrooman Apr 16, 2016:
@Mark and Tony

I referenced this in the very first discussion entry:
"In older material you’ll run across 'degrees Kelvin,' symbol °K, but that usage was officially declared obsolete in 1980."

@Charles
The thing is Cilian asked about "university textbooks." Someone will have yet to provide a reference for those. I did it for high school textbooks in the US and I guess my last link for the UK, but I haven't had the time yet to check for university textbooks. I find it a bit difficult sometimes - German university courses are very different (at least in comparison with the US). There is no general education at the beginning and books are rarely given out (more like PowerPoints, etc.).
Mark Nathan Apr 16, 2016:
Agree with Charles that not pluralizing kelvin is probably a throwback to the habit of saying "degrees Kelvin" (which I have from being taught physics at university in the late eighties).
Charles Davis Apr 16, 2016:
What I mean is that not pluralising "kelvin" is completely illogical. There's no more reason to say "100 kelvin" than "100 amp" or "100 joule". The only possible justification is custom, and that's what the CERN rule must be based on: people don't pluralise it because they're not used to doing so and it sounds wrong to them (as it does to you, because people who taught and worked with you didn't say it). And this quite probably arose from the fact that when they stopped being called degrees people simply dropped the word "degrees" and started saying "100 kelvin", as a sort of ellipsis for "100 degrees Kelvin", without taking the further step of adapting the morphology.
Charles Davis Apr 16, 2016:
My guess (and it's only a guess) is that "kelvin" as a zero plural is a hangover from the pre-1968 days when it was officially "degrees Kelvin". People were taught by people who had grown up talking about degrees Kelvin, and "kelvins" sounded wrong to them. But as far as I can see kelvin is no more a mass noun than any other SI unit. You can have a kelvin, can't you? If so you can have several kelvins.
Charles Davis Apr 16, 2016:
@Neil If you check back you'll see that I had already quoted the CERN guidelines on this.

To my mind it seems pretty clear that "298 kelvin" and "298 kelvins" are both in common use, but given that "kelvins" is in line with general usage, which is to pluralise units (with very few exceptions: lux, hertz and siemens are just about the only ones and all for the obvious reason that they end in a sibilant, which is not true of kelvin), I firmly believe that it would not be justified to change "kelvins" to "kelvin" in a text you are editing. You should only change what's wrong, and this isn't.
Neil Ashby Apr 16, 2016:
FWIW Googling for "Langmuir" (one of the leading papers in physical chemistry) + "measured in kelvin" > 8900 hits
"Langmuir" + "measure in kelvins" > 1400 hits

You can try the same with other leading physics/chemistry publications.
Neil Ashby Apr 16, 2016:
IMO it's a mass noun and has no plural. FWIW - "kelvins", in plural sounds very odd to me. I spent 4 years in a physical chemistry lab where temp was always quoted in kelvin - no plural. "298 kelvins" sounds wrong, like an error one of the non-anglophones in the lab would say. But I see from the difference between standards and guidelines that there is no standard - ho-hum, when is there.

I will leave you with the CERN's usage advice:

kelvin

"Spell out on first mention; note the lower-case k (all SI units are lower case when spelled out); can be abbreviated to K in subsequent mentions. And note that it is always kelvin, even when plural (not kelvins or degrees kelvin)."
http://writing-guidelines.web.cern.ch/entries/kelvin
Charles Davis Apr 16, 2016:
By the way Someone should post an answer, I feel, but I'm at the back of the queue. Björn? Tony?
Charles Davis Apr 16, 2016:
As my second reference says, "degrees Kelvin" went out in 1968 and they started to be called simply kelvins.
It also points out that if you were writing for CERN you would use a zero plural, but still lower case. CERN is out of step here:

"kelvin
Spell out on first mention; note the lower-case k (all SI units are lower case when spelled out); can be abbreviated to K in subsequent mentions. And note that it is always kelvin, even when plural (not kelvins or degrees kelvin)."
http://writing-guidelines.web.cern.ch/entries/kelvin
Charles Davis Apr 16, 2016:
kelvins is right; don't change it Official SI practice is kelvins, apart from other considerations:

"The kelvin, unit of thermodynamic temperature, is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
It follows that the thermodynamic temperature of the triple point of water is exactly 273.16 kelvins, T<sub>tpw</sub> = 273.16 K. [...]
A difference or interval of temperature may be expressed in kelvins or in degrees Celsius (13th CGPM, 1967/68, Resolution 3, mentioned above), the numerical value of the temperature difference being the same."
http://www.bipm.org/utils/common/pdf/si_brochure_8_en.pdf

Worth reading this:
http://physics.stackexchange.com/questions/114079/are-there-...
Tony M Apr 16, 2016:
Most SI units take a lowercase initial letter when written in full, even when a capital letter is used for the unit itself when abbreviated (many of which units were derived from people's names: V(olt), T(esla), A(mpère), W(att), etc.) I believe there is one exception to this rule, but can't remember which it is now; I had a feeling it was Ohm, for which the abbreviation is a Greek capital omega, but I may be wrong on that point.

So 'kelvin' with a l/c 'k' is no exception to the standard rule; likewise, it is normal practice to add the plural 's' on units when spelled out (which of course would NOT be added when abbreviated!) — so 'kelvins' also follows standard SI practice.

AFAIK, the only thing special about 'kelvins' is (as has already been noted) they are NOT 'degrees kelvin' — note in passing that if they had been, then it would have been the 'degrees' that took the plural!
David Hollywood Apr 16, 2016:
Bjorn is on track
Cilian O'Tuama (asker) Apr 16, 2016:
It's a start alright. Let's see where that takes us. Ciao for now, c
Björn Vrooman Apr 16, 2016:
Does that count? UK Department of Education, GSCE subject content:
https://www.gov.uk/government/uploads/system/uploads/attachm...

Appendix 2, page 48

Then there's the book by Roger Muncaster "A Level Physics":
https://books.google.de/books?id=Knov8XAyf2cC&printsec=front...

Has "kelvins" in it too. Sorry that I can't be of better help right now, but I thought it's a start.
Björn Vrooman Apr 16, 2016:
I believe I can. At least, when it comes to high schools. The following physics books were the most widely used ones in the US up to 2009:
https://www.aip.org/sites/default/files/statistics/highschoo...

Holt Physics (Serway, Faughn, Holt McDougal)
Physics Principles and Problems (Zitzewitz / McGraw Hill)
Conceptual Physics (Hewitt / Addison-Wesley)
Physics: Principles with Applications (Giancoli /Prentice Hall)

The second and fourth one have no preview in Google Books. But the first and third one have a snippet view. If you type in "kelvins" as plural, both Holt and Conceptual Physics will show you examples.
Cilian O'Tuama (asker) Apr 16, 2016:
I'm aware of most of that Björn, thanks. Can you quote a university textbook?
Björn Vrooman Apr 15, 2016:
More on it: "Thus temperature intervals or temperature differences may be expressed in either the degree Celsius or the kelvin using the same numerical value."
http://www.nist.gov/pml/pubs/sp811/sec08.cfm

As you can see, the abbrevation is capital K, but the spelled-out one starts with a small letter.

Actually, even Oxford says so, also mentioning the plural form:
http://www.oxforddictionaries.com/definition/english/kelvin

AFAIK, both versions (with or without plural) are acceptable. But kelvin usually starts off with a small letter (same as: watt but W).

Have a good night
Björn Vrooman Apr 15, 2016:
@Cilian FAQ from the US Metric Association:
"It’s K for kelvins, not °K.

It’s 'kelvins' (small k) with the symbol K (capital K).

In older material you’ll run across 'degrees Kelvin,' symbol °K, but that usage was officially declared obsolete in 1980.

Celsius temperature is expressed in degrees Celsius (small “d,” capital “C”), with symbol °C. The old term 'degree centigrade' was officially declared obsolete in 1948."
http://www.us-metric.org/faq-frequently-asked-questions-abou...

Does that help some?

Responses

+3
2 days 20 hrs
Selected

kelvins or K

This issue has been debated extensively in the discussion box. Please have a look there to find more information compiled by my colleagues. The following is just a summary.


A) Dictionaries,...
http://www.oxforddictionaries.com/definition/english/kelvin
http://www.macmillandictionary.com/dictionary/british/kelvin
http://www.merriam-webster.com/dictionary/kelvin
http://www.thefreedictionary.com/kelvin

B) ...official guidelines,...
http://www.us-metric.org/faq-frequently-asked-questions-abou...
http://www.metoffice.gov.uk/media/pdf/k/o/Appendices.pdf
http://www.nist.gov/pml/pubs/sp811/sec08.cfm

C) ...high school textbooks,...
Holt Physics (Serway, Faughn, Holt McDougal)
Conceptual Physics (Hewitt / Addison-Wesley)
[two of the most widely used textbooks in the US up to 2009; both available as a Google Books preview]

A-Level Physics (Roger Muncaster)
[also available as a preview]

D) ...and university textbooks...
https://fisluisabraham.files.wordpress.com/2014/08/krane-k-m...
https://docs.google.com/file/d/0B_FOFMzF0_0gbjNxakkzUkV4dzg/...

...all seem to agree on lowercase k for kelvin, a regular plural form (kelvins), uppercase K for the abbreviated unit and Kelvin with an uppercase K if "scale" or similar is added (e.g., http://www.oxforddictionaries.com/definition/english/kelvin-... ).

Well, all seem to agree but one: CERN (http://writing-guidelines.web.cern.ch/entries/kelvin). And there may be some exceptions found in government documents (https://www.gov.uk/government/uploads/system/uploads/attachm... ). As they go against general and textbook usage, I cannot recommend them here. In such cases, you may have to fall back on specific guidelines if they have been made available to you.

On a side note: The description "degrees Kelvin" is obsolete. It fell out of favor at the latest in the 1980s - if not earlier (http://www.bipm.org/en/CGPM/db/13/4/ ).

In brief: If your textbook isn't funded by the IAEA, I'd recommend word usage as stated above.
Peer comment(s):
agree Tony M : I grew up with '°K', but it was already deprecated by the late '70s / 'Celsius' has already gone that way, a long time ago!
2 mins
Thank you, Tony :) Glad they didn't try that with Celsius or we would have "celsiuses" by now!
agree Mark Nathan : Celsius will be next
11 mins
Thank you, Mark :) I hope not. Anders Celsius may start spinning in his grave.
agree Charles Davis : No reason why Celsius should follow; it's not an absolute scale.
11 hrs
Thank you, Charles :) Of course, you are correct, but considering all the different opinions, I can no longer be sure of anything.
Something went wrong...
4 KudoZ points awarded for this answer. Comment: "Thanks again to all."
Close search
Term search
  • All of ProZ.com
  • Term search
  • Jobs
  • Forums
  • Multiple search