Talk:Kilogram/Archive 7

NPOV issuse in article.
An editor is insisting that unsourced and uncited text remain in the article. namely this"


 * This small difference, and the fact that the mass of the IPK was indistinguishable from the mass of the Kilogram of the Archives, speaks to the scientists’ skills over 225 years ago when they made their measurements of water’s properties and fabricated the Kilogram of the Archives.

Without any source to back this up it cannot remain in the article. Please read WP:V and find a WP:RS for it before re-adding. HumphreyW (talk) 03:45, 1 February 2011 (UTC)


 * Could I ask everyone to remain calm here, and take a step backwards for a moment? This doesn't appear controversial text, so it won't do any harm to leave it (with the tag—which I've added) for a while to see if someone can improve it. GFHandel .  03:56, 1 February 2011 (UTC)


 * No kidding. User:HumphreyW: Please don’t editwar over a common sense point. This edit you are just insisting on is not supported by Wikipedia policy. Citing sources states that citations are needed “for any material challenged or likely to be challenged.” It doesn’t state that citations are needed for stuff HumphreyW doesn’t like. That text has been there for years without challenge for one reason: it’s obvious that scientists who worked to an accuracy of 25 parts per million way back in 1799 did darn good work. I see now, that as a result of your incessant insisting on citing common sense, GFHandle tried to find a middle ground where people can now run around looking for a citation out of Readers Digest that states the drop-dead obvious. Greg L (talk) 04:02, 1 February 2011 (UTC)


 * Actually, I doubt that "improving" it is going to help much. I don't see this text as adding any value to the article about the Kilogram. This article is not about the relative skills of scientists of the past. The text is merely speculation, it gives no reference point for comparison about other levels of accuracy for other units of measurement. It is just handwaving and unencyclopaedic. HumphreyW (talk) 04:08, 1 February 2011 (UTC)


 * Actually, how is this common sense? It is not common sense for me, I have never studied the history of metrology, I have no idea of the relative merits and difficulties for 1799 engineering. More handwaving here, this is not something "everyone just knows". And if everyone really does already know it then why put it in the article? HumphreyW (talk) 04:08, 1 February 2011 (UTC)
 * Well, I’m a mechanical engineer with 15 patents. So what’s “common sense” to me might indeed be strike others as “baffling beyond all comprehension”. You might try more judicious use of the {fact} tag rather than that splendiforous [delete] key. Common sense is no-doubt a subjective thing and is most properly gauged by the middle of the bell curve of our readership (which no-doubt underlies why that text was there unchallenged for so many years). Greg L (talk) 04:35, 1 February 2011 (UTC)


 * I'm just pleased that the horrific scientific-accuracy-kilogram-based-3RR saga of 2011 has been averted. Whew. I'm guessing that lots of editors watchlist this article, so let's wait to see how others react. GFHandel . 04:22, 1 February 2011 (UTC)

(after sleeping on it) I revised that sentence so it makes no mention of anyone’s “skill”, states a pure fact, and makes the direction of the error explicit (the Kilogram of the Archives was a bit heavier than it should have been) so as to better serve the interests of the readership. It now simply states the facts: that the scientists two-hundred-plus years ago made the Kilogram of the Archives so it was heavier than a liter of water by the weight of a rice grain. Perhaps some will think “that certainly speaks to their skill” whereas still others might think “how crude.” It is what it is. Greg L (talk) 18:53, 1 February 2011 (UTC)

Some slack for the guy who has worked the hardest here?
As an uninvolved editor, might I suggest that we give Greg L. (who I do not know except from reading here) a bit of slack on the writing of this article? He has obviously studied the subject more than anybody else we've found, and is well-motivated to produce a good history. Though we strive for NPOV, that only means fair representation of POV's in the published literature, not literal NPOV. So far as I can tell, Greg L. has not departed from this very much. I do not mean automatically giving Greg L. anything he wants-- I'm just suggesting that we remember that we're lucky to have him as a reviewing expert on a subject which would be rather technical and dull for the rest of us, if we didn't have him. Personally, after reading the history here (most of which he's written), the subject managed to "come alive" for me. That says something, since like most people, my eyes tend to glaze-over when confronted with the details of scientific metrology and standard-making. So, try not to drive the guy off, okay? S B Harris 17:41, 6 February 2011 (UTC)

I need help to correct a statement
This statment about the proposed new definition occurs in the article:
 * "... it would be defined in electrical terms in a manner that is directly traceable to just two fundamental constants of nature."

This statemant is not correct. The Proposed new definition fixes the Plank constant. From New SI definitions:
 * Proposed definition: The kilogram, kg, is the unit of mass; its magnitude is set by fixing the numerical value of the Planck constant to be equal to exactly 6.62606X×10−34 when it is expressed in the unit s−1·m2·kg, which is equal to J·s.

The Plank constant relates seconds, metres, and kilograms. There are no "electrical" terms in the proposed new definitions. The watt balance employs clever electrical techniques to determine the mass of a test sample according to this definition, but those terms to not occur in the definition. There are a total of three additional "fundamental constants of nature" here:
 * Planck's constant h is exactly 6.626 06X  ×  10−34  J·s.
 * The speed of light c is exactly 299  792  458  m/s.
 * The ground state hyperfine splitting frequency of the caesium 133 atom Δν(133Cs)hfs is exactly 9 192  631  770 hertz.

It is not instantly obvious to me how to correct this statement. I think we need to re-write a small segment of the article. -Arch dude (talk) 00:02, 5 February 2011 (UTC)
 * I changed the statement in the main article. I'm sure that my change is technically correct, but I would appreciate it if someone will review it to see that it conveys the correct information to a general reader. -Arch dude (talk) 23:45, 5 February 2011 (UTC)

Redefinition of the kilogram

 * Quote from the article:*

If the IPK’s value were definitively proven to have changed, one solution would be to simply redefine the kilogram as being equal to the mass of the IPK plus an offset value, similarly to what is currently done with its replicas; e.g., “the kilogram is equal to the mass of the IPK + 42 parts per billion” (equivalent to 42 µg).


 * End of quote.*

The ending equivalence would naturally only be valid until the kilogram is hypothetically redefined, thus never correct once relevant. To clarify: the 42 ppb. are wrt. the IPK while the equivalent is spec'd wrt the kg. They are thus equivalent if and only if the IPK is equivalent with the kg.

I added a in the hopes that someone with better grasp of scientific English or the subject matter than myself might amend this fallacy, but the change was reverted and I'll leave it as a comment on this talk page.

Eroen (talk) 19:53, 15 March 2011 (UTC)


 * I suggest deleting the phrase "(equivalent to 42 µg)". :-) --Steve (talk) 02:56, 16 March 2011 (UTC)


 * This wouldn't really be a solution, rather a temporary workaround. They would have to keep redefining it.  When they found out that the size of the earth had changed (or had not been measured accurately, whatever), did they redefine the metre to the effect of "1/10001966 of the distance from the north pole to the equator", or did they skip straight to other ways of defining a unit of length? — Smjg (talk) 12:34, 7 May 2011 (UTC)
 * These are analogous conceptually but not pragmatically. Right now, measuring the ratio of the mass of a macroscopic object to that of a platinum cylinder is much easier than measuring that of the same mass to the Planck constant or the mass of a carbon-12 atom (i.e., the former doesn't require several years and more than a million dollars), so redefining the kilo in terms of ħ or NA would initially make things harder rather than easier for macroscopic mass metrology. ― A. di M.​plé​dréachtaí 21:11, 23 June 2011 (UTC)
 * @Eroen: I think the difference bw 1/(1 − 42) and 1 + 42 (the mass of the IPK in new kilos as specified by those two wordings) is waaay smaller than the precision any mass will ever be measured in the next 60 years. :-) ― A. di M.​plé​dréachtaí 21:11, 23 June 2011 (UTC)

Metric ton
"According to the BIPM, 'In English speaking countries this unit is usually called "metric ton".'" This may be the case but if so, they've got it wrong. In Australia, for example, it's always a tonne. Can we find a source on this? J IM ptalk·cont 16:38, 30 May 2011 (UTC)
 * See this:, . (Using these as sources would be a tad WP:OR-y, but still...) ― A. di M.​plé​dréachtaí 20:49, 23 June 2011 (UTC)

better picture needed
A picture showing the IPK with an inch scale (and especially without a metric scale) is not exactly what this article needs... Is there a copyright issue with this one or why hasn't it been used? --Espoo (talk) 12:44, 6 February 2011 (UTC)
 * Well spotted Espo. There is a copyright statement associated with the picture - [|The BIPM holds copyright on the textual and multimedia information available on this website, which includes titles, slogans, logos and images, unless otherwise stated. Reproduction is authorised, except where otherwise stated, if the source is acknowledged and if the information reproduced is not subject to any distortion, addition or mutilation. Copyright of any third-party materials found on this website must also be respected.. I believe that this does not prevent the picture being used in Wikipedia, provided that the correct acknowledgements are made. [[User:Martinvl|Martinvl]] (talk) 13:08, 6 February 2011 (UTC)

The existing image was computer-generated from a computer model by User:Greg L. Perhaps he will be willing to generate one with a Metric ruler? I am not a lawyer, but I'm not comfortable that the BIPM copyright is compatable with WP's copyright rules, since the BIPM license is more restrictive than CC-BY-SA. For example, CC-BY-SA permits derivative works, which would include distorted images. -Arch dude (talk) 17:31, 6 February 2011 (UTC)


 * Are you serious, Espoo?? All this because you had to look at an inch-based ruler?  We’ve been through this before. Tell you what: Why don’t you Espoo, contact the BIPM and get them to send you a picture of the IPK? The one you proposed shows a vault and some glass bell jars; it doesn’t illustrate the IPK whatsoever . What’s the caption supposed to say? (“The IPK is in here somwhere—trust me”)? Did you know I contacted APCO to get the silicon sphere photo. I exchanged a dozen e-mails before the head of the lab finally released a picture that was on their Web site into the public domain and released it to Wikipedia. You can do the same thing. Let’s see… what’s it take for those BIPM guys to even open the vault to gain access to the IPK? Three keys possessed by different individuals! Good luck. As to why there is an inch-based ruler, Wikipedia is a collaborative writing environment where all content is generated by volunteers who (sometimes) have day jobs. I work for a living (I don’t contribute to Wikipedia from my parent’s basement). I’m a medical researcher and am an R&D engineer. I happen to have generated that entire virtual photo studio in a CAD program for a medical device and recycled the studio for the purpose of creating an illustration to illustrate “IPK”. The rest of my response on this subject is addressed simply by referring you to the last time someone was deeply offended by the juxtaposition of the foundation of the metric system and and a unit of measure used by Americans. See Talk:Kilogram/Archive_5. One of the things mentioned there is this: You might also notify the other non-English versions of the Wikipedia Kilogram articles (these: be-x-old, cs, da, ka, sw, It, hu, mn, ja, sr, ay, bs, es, it, ru, and zh-yue), as well as GA Tech University because of this press release)—all of which are using this very same image I created. We can’t assume that the editors responsible for these image placements were all properly aware of this “inch-based ruler” issue when the editors at these all-metric countries made their individual decisions to also use the image. And just think of the millions of poor unfortunates who were shown an American inch alongside the last artifact underpinning the metric system and were given no advance warning to have young children leave the room. We certainly can’t afford to have any readers suffering a forehead-hemorrhage after they realize the true nature of that ruler! As to creating another ruler in metric: no. The CAD program I own has a bug in the way it applies decal-type numeric legends to 3D solid models; numerals with closed letters, like 4, 6, 8, and 9 leave voids in their loops that blocks out the wood-grain decal underneath. Go back and take a look at that ruler. Notice how there aren’t any numerals behind the IPK in the darkness? That’s because the “4” and “6” weren’t working and the “2” and “3” are hidden behind the IPK. I figure a $3000 CAD program that I actually own and didn’t pirate (*sound of audience gasp*) is good enough for a volunteer contribution. I thought the couple of evenings I spent making that über-realistic ruler in the first place for my medical work was—you know—good enough (foolish, fooshish me). The research and effort I’ve put into this article—like pretty much all wikipedians—is a labor of love. All hobbies are. Reactions like yours is a big buzz-kill. So… Your options are as follows:


 * Contact the BIPM and get them to send you a picture that actually shows the IPK and release it into the public domain. This is my preferred alternative, BTW. Oh… and as I recall, I contacted the BIPM years ago when I first started on this article with that very question and they didn’t even respond; (like in the movie Ratatouille: “Sorry to be rude, but we are French.”)
 * Go get yourself $3,000 to $5000-worth of software and learn how to create virtual studios with strategically placed lights (mirrored objects are hard to light) and do a better job with a metric ruler and donate it to Wikipedia.
 * Get a rescue inhaler to cure your asthma attacks when you see an inch-based ruler next to a metric-something.
 * Send me $1000 for the one or two evening’s worth of effort of my horsing around making a metric ruler that doesn’t offend your metric sensibilities. That’s what it would take to get the “loving feeling” back to what is supposed to be a labor of love.
 * Hire some other CAD expert (because I might turn down the $1000 since I’m busy lately).


 * In short, try enjoying the look of the IPK. Now you know what is looks like. I dredged up the actual blueprints for the thing when I made that geometry. That there is an inch-based ruler behind it doesn’t really matter. Oh, please advise if there is an example of some work you contributed to Wikipedia that you are particularly proud of and which the rest of the Wikipedia world has copied because it fills a universal need. I’ll go inspect it with pouted lower lip and come whine about some beyond-trivial aspect of it and suggest something that is utterly inane to replace it. Greg L (talk) 20:55, 6 February 2011 (UTC)

Greg L is unwilling to provide a GCI image with an SI-based ruler. Does anyone else wish to provide one? Note that we do not need a full-up CAD model. We can just "post-process" the existing image. This can be done in Gimp or Photoshop if someone has the skills. -Arch dude (talk) 12:48, 7 February 2011 (UTC)


 * I am “unwilling.” Yes, I wanted to go metric, but because of the bugs in my CAD program with typed-in lettering over decal maps like woodgrain, I would have to spend a couple of evenings to hand-draw numerals. That’s not gonna happen. There are some 18 other-language Wikipedias that use this image. And I was contacted by an author who was writing a book and his publisher required that I release the image specifically to them because the GNU license wasn’t good enough for them. So somewhere out there is a full-tilt color book with this image. I’m just not exactly seeing any reason to be all motivated to spend a few evenings just so I can add User:Espoo to the list of happy campers; particularly since your objection isn’t over the factual accuracy of anything, nor is the objection over shortcomings in the realism of the rendering, nor the attractiveness of the image; you just don’t like “inches” in an image showing the IPK (which is actually an advantage for the American-portion of our readership, who most need to understand the kilogram). I suggest that rather than soliciting others to get cracking to please you, you might lift a finger and—you know—actually do something like contact the BIPM and see if they have a photograph of the IPK that they are willing to release into the public domain. Now that would be a welcome improvement over a CAD rendering for the purposes illustrating “IPK” and “Kilogram”—at least until such time that the watt balance illustrates ‘kilogram’. Greg L (talk) 00:07, 8 February 2011 (UTC)

I think this one is worse than Greg L's, even if we had copyright permission, because there's no sense of scale...which is the whole point. That cabinet could be huge or tiny, you can't tell from the cropped photograph. Say what you will about the inch-based ruler, it's surely better than nothing. If I were going to change it (and I'm not!) I would choose neither an inch-based ruler nor a cm-based ruler, but an apple or a coin or a pen or a bottle of wine or something like that which everyone would recognize and relate to. (No offense Greg I'm not complaining!!!) :-) --Steve (talk) 03:22, 8 February 2011 (UTC)
 * Understood. I might be able to make one with a golf ball (the two have nearly the exact same volume). Now, an apple; that would be double-tough. Greg L (talk) 17:18, 8 February 2011 (UTC)
 * That's a neat idea that conveys the spatial scale, but still doesn't get the density across. One kg is approximated by the mass of 21.77 regulation golf balls, which (sadly) doesn't give a neat pyramidal stack, but you might be able to stack 14 full-balls on 16 half-balls and V-notch the top one for the 0.77, if you really feel ambitious. But golf is a bit out of reach for most of the world. The 1 litre(-er) plastic water bottle might be more universally familiar, if less elegant.LeadSongDog come howl!  18:50, 8 February 2011 (UTC)


 * LeadSongDog, you're thinking of an illustration of "kilogram", not an illustration of the IPK. Both are valuable but they should be separate. For the former, how about File:Coke_2litre_bottles.jpeg, "A 2-liter bottle of soda weighs about 2kg." Anything better? 2L bottles of soda are universally familiar right? (Too universal IMHO...) Any other suggestions?
 * By the way, Greg L, I can imagine lots more important things on wikipedia to do besides making a perfectly good picture even better. If you would enjoy changing the picture then I don't want to discourage you... but you should not feel pressured! Just my opinion. --Steve (talk) 21:04, 8 February 2011 (UTC)
 * No, I was indeed thinking of the IPK illustration. An inexpert viewer can't readily tell if the image shows a Pd, Pt, or even Mg cylinder, so while the juxtaposition with a golf ball conveys a good sense of its diameter and length to anyone familiar with golf balls, it doesn't convey a sense of the mass at all. For many, an image of eight rolls of fifty Lincoln head pennies (nominally 2.5 g each) would do that readily while also conveying the diameter of the juxtaposed IPK. However, I don't really wish to quibble. Greg has produced a very nice image and we should appreciate it as such. The inch or mm rule is to me a very low priority issue, compared to the gaping holes elsewhere on WP. LeadSongDog come howl!  22:00, 8 February 2011 (UTC)

Thank you LeadSongDog and Steve; I agree with you both. There is no possible way to convey a sense of the magnitude of the mass of a kilogram in an illustration and there is no point even pondering such a thing—not at least until after the invention of “teleforce”, which is a technology that will ultimately be sued out of existence in a future class-action lawsuit over the broadcast of a National Geographic travelog showing an elephant stampede (a legal phenomenon that will also doom smellovision after careless camera work). The text in the lede conveys the magnitude of the mass just fine: it’s close to the mass of a liter of water. ‘Nuf said.

The entire point of the illustration was to show what the IPK looks like. Anything that provides a sense of scale helps. The caption can also be improved to help in this regard, so I just now revised the caption to mention that the IPK is about the size of a golf ball. The IPK, BTW, has a volume that is about 15% greater than a golf ball but also has a diameter about 8.5% smaller than a golf ball, but such detail in a caption is unnecessary to convey the general nature of the size of the beast.

Regardless of the graduations on the scale, I’m sure rulers capable of clipping into 3ring binders are available in Canada, England, Australia, and the other English-speaking countries. That this image has been adopted for use by dozens of other-language Wikipedias suggests that this image is sufficient to serve the purpose of illustrating “IPK”—and all those other-language Wikipedias are used by metric-only countries.

I’m sure there are exceedingly *enlightened* editors who would preach to we non-worldly, insensitive types that Mongolian yak herders will have almost certainly never seen a golf ball so mentioning such in the caption is not sufficiently universal. I duknow how to help that. The English-language version of Wikipedia is geared to the middle of the bell curve of our readership; that being our readership for whom English is their first language. Invariably, such a readership has seen a golf ball first hand—so mentioning “golf ball” in the caption (instead of just the body text) helps.

As I mentioned above, I had set out to make a complete ruler. It is modeled in exquisite precision and fidelity after an actual ruler I still own…all the way down to the micro-texture in the brass pen guide (detail that can only barely be seen in the 1400-pixel version I uploaded). I just now looked at my CAD model; that virtual photo studio contains 12 light sources. But, as I also stated above, a bug in how my CAD program handles text decals over wood decals prevented me from adding certain numerals starting with numeral “4”. So I had to settle for partially completing the inch-side of the ruler—even for my own medical illustrations (after six years of effort, human trials on a game-changing device are coming up soon, BTW). In the end, which side of the ruler faces the viewer is just a “You say ‘to-MAY-to’ – I say ‘to-MAH-to’&thinsp;”-thing; something I can get to at another time. Greg L (talk) 22:48, 8 February 2011 (UTC)


 * I have thought of finding a pineapple and photographing it next to a tennis ball to give an idea of size. BTW, we don't use 3-ring binders in the UK - the norm is 4-ring binders with holes spaced 80 mm apart. (by User:Martinvl)
 * Yes, I’ve seen the 4-hole ones. Some rulers sold in the U.S. feature hole patterns to work in either 3-ring or 4-ring binders. Even more so than with a golf ball, virtually every English-speaking person has seen a ruler and has a darn good idea how big they are. Greg L (talk) 16:01, 9 February 2011 (UTC)

FWIW, I'm a fluent English speaker who uses the English WP almost esclusively and spent nearly nine months in an English-speaking country, but I can't remember when I last saw a golf ball (probably more than a decade ago) and I'm not sure that I could guess its diameter better than to within a factor of 1.5 (i.e. its volume better than to within a factor of 1.53) off the top of my head. ― A. di M.​plé​dréachtaí 21:19, 23 June 2011 (UTC)
 * I wrote down a guess and then looked it up, and my guess was about 20% too small. ― A. di M.​plé​dréachtaí 21:25, 23 June 2011 (UTC)

IMHO the picture of 1 liter of distilled water would be easier to obtain and would give to anyone a good idea of the mass involved. -- Basilicofresco  (msg) 12:39, 26 June 2011 (UTC)
 * Something like that was discussed at /Archive 6. ― A. di M.​plé​dréachtaí 13:29, 26 June 2011 (UTC)

Why can't this picture be used for the IPK? Will BIPM allow this photo to be used? Are there copyright issues that prevent someone with a legit Wikipedia login to upload the pic into Wikimedia? GregL, I remember when you created the rendering, and I thought it was because BIPM did not grant Wikipedia to use their pic and some nasty photo eliminator in Wikipedia ditched the BIPM photo. We also had photos of American copy prototypes and I once used them in the article (as far back as 2006 or something) and the US gov does grant unrestricted use of its published photo. They nixed that one too. 71.161.194.186 (talk) 22:11, 26 June 2011 (UTC)

Child's weight
The child's weight is only supported completely at the bottom of the arc. At the horizontal it would not be supporting any of the weight. — Preceding unsigned comment added by 81.135.19.124 (talk) 16:45, 30 May 2011 (UTC)

Decigram redirects to Kilogram
For some reason Wikipedia redirects "decigram" to this, the kilogram, article. From what I gather, and indeed what a number of other sites claim, a decigram is one-tenth of a gram; several orders of magnitude in difference from a kilogram. I was VERY confused until I was eventually forced to conclude that the redirect was inappropriate at best and misleading at worst.

I suspect that this redirect exists simply because there is no requirement for a page unique to the decigram, but, I would strongly suggest that someone change the redirect to a more suitable article or at the very least include some information stating that the two units of measurement are not the same. My suggestion would be the SI Prefix article.

If I were familiar enough with the workings and policies of Wikipedia, I would likely do this myself, but in this case I would prefer to leave the decision to someone better qualified. — Preceding unsigned comment added by 77.98.156.182 (talk) 09:25, 19 June 2011 (UTC)
 * Thanks for this observation. I changed the redirect to point to Orders of magnitude (mass), which is still not quite right, but it is better. We have individual power-of-ten articles for length and time, but not for mass. If someone eventually decided to create that series of articles for mass by subdividing the Orders of magnitude (mass) article, then "10-4 Kg" will get its own article and Decigram can link to it. In the mean time, I will add some additional introductory material to that article. -Arch dude (talk) 13:55, 19 June 2011 (UTC)
 * Well that was interesting. The set of redirects from yottagram through yoctogram was in a state of total disarray. I normalized them to redirect to Orders of magnitude (mass), except for a few that are real articles (which now link to that article) and I added more explanatory text to that article. This may not the the correct solution but at least it's consistent. -Arch dude (talk) 23:39, 20 June 2011 (UTC)
 * I had already noticed that two years and a half ago: see Wikipedia talk:WikiProject Physics/Article titles about multiples and submultiples of units. (Army1987 was me.) ― A. di M.​plé​dréachtaí 20:32, 23 June 2011 (UTC)

Gram and tonne equivalents
In the section Kilogram, the table lists (tonne) as equivalent to 106g. I'd like to see other equivalents there as well, e.g. megatonnes and gigatonnes - I don't see any harm in it. I couldn't see how to edit that table, though. --Chriswaterguy talk 13:44, 25 September 2011 (UTC)
 * Megatonnes and Gigatonnes belong in the article tonnes (maybe), not here. Martinvl (talk) 21:24, 25 September 2011 (UTC)
 * I added a link to the Orders of magnitude (mass) article, which discusses this and gives examples. ~

DeFacto's changes 2 November 2011
I have undone DeFaco's changes. Martinvl (talk) 20:07, 2 November 2011 (UTC)
 * 1) The statement "The chiefly British-English spelling kilogramme is also in common use" is unsourced; moreover the preceding sentence (list list of standards agencies) contradicts this statement.
 * 2) The statement "Kilo is a widely used abbreviation" is incorrect ("kilo" might be used as slang). The kilogram does not have abbreviations, it has an internationally-agreed symbol - "kg".


 * Martinvl, None of that 'note' is reliably sourced; why did you single-out just the bit that I added for deletion - when you should have removed it all or added a tag to it all? How do you suggest we proceed? Will you provide sources for what you left there, or shall we remove it? -- de Facto (talk). 21:51, 2 November 2011 (UTC)


 * I couldn't figure out how to add references within a note, so I've added them at the text level. "Kilo" is a widely used abbreviation - people don't say "I'll have 0.454 kg of strawberries please" (it doesn't exactly roll off the tongue), they say: "I'll have 0.454 kilos of strawberries please"! I haven't re-instated the "widely used" bit yet, as a Google search result (which proves it) won't pass as an RS - do you have any suggestions for how to source that? We also need a reference for the ''kilogramme' spelling being "in common use" - again a Google search confirms it. -- de Facto (talk). 22:39, 2 November 2011 (UTC)


 * If I may wikistalk the both of you. This book and this published seminar paper state that kilogramme is acceptable in British English (use that rather than "commonly used"?), although it may be slowly dying out. On the other hand, it is correct that the formal SI spelling is kilogram. As for "Kilo", I've checked several dictionaries and they list it as an abbreviation of kilogram without calling it slang. For a credibility check on this (ie it's not RS secondary, but still...) you can look at www.americanncorpus.com finds many examples of kilo used as an abbreviation for kilogram, as well as a google books search on the phrase "a kilo of" to see the kinds of formal publications it turns up in.
 * It seems to me that there needs to be made a distinction between "official" usage, and common usage. Both are of interest to scholars.VsevolodKrolikov (talk) 09:56, 3 November 2011 (UTC)


 * I checked the SI Brochure which is the definitve guide to SI. It states categorically that abbreviations are not permissable for unit or symbol names. Since the authoritative text is the French text, I quoted that in a note.  For the record, the authority behind the SI Brochure is the Treaty of the Metre (1875) to which most of the world's larger nations have signed up.  The various dictionaries have no equivalent authority, but merely reflect what is actually used.  Therefore, if market traders persistently write "Bananas 60p/kilo", the OED will catalogue that, but the SI Brochure follows the French model - no word can formally be accepted into French until it has been approved by the French Accademy. Martinvl (talk) 20:56, 3 November 2011 (UTC)


 * Ironically enough, the dictionary of the Academie Francaise lists "kilo" as
 * KILO n. m. XVIIIe siècle. Abréviation courante de Kilogramme.
 * But that's by the by, English lexicographers have long been of the descriptive, rather than prescriptive frame of mind, and what is important to them is attested usage. (Manuals of style, if they exist, vary from institution to institution). The OED has always been descriptive, and that's probably the strongest authority in terms of what is considered English. The typical terminology among linguists is "acceptable" or "accepted" for an item of language, suggesting it is widely enough attested. For example, "On the weekend" is accepted use in the US, "at the weekend" is accepted use in the UK.
 * A parallel case to the one here might be that of cesium/caesium. The latter, much to the vicious outrage of a large number of US wikipedians, is the official spelling according to IUPAC, which is our arbiter of article titles on elements. That does not mean that an American, writing for an American audience, is spelling caesium wrongly when he writes cesium. Similarly, a Briton is not considered wrong when they write sulphur in a British context rather than sulfur, even though sulfur is the official spelling according to IUPAC.
 * As such, what is important here is to note official and recommended uses, as well as what lexicographers have identified as "acceptable/accepted" use in varieties, or across the whole of, English. This would be to reflect scholarship. As such, kilo is noted in authorities as an acceptable alternative to kilogram(me) in English in general communication, but is discouraged in science writing (presumably that can be sourced to widely used manuals of style somewhere). Given that kilo(gram((me)))s are used in everyday life, all this is relevant. Were we talking about an obscure technical term, it might be different, because then we'd be talking about a small number of attestations outside the specialist area that might not even be due (no RS coverage).VsevolodKrolikov (talk) 03:54, 4 November 2011 (UTC)


 * The Guardian style guide does not permit "kilo": its on-line and paper verions (next to my keyboard as I write) do however differ regarding the use of "kilogram" and "kilogramme". I have tried looking at a numbe rof otehr style guides but in the last few months many have ceased being free. — Preceding unsigned comment added by Martinvl  (talk • contribs)  08:58:30, 6 November 2011 (UTC)


 * Martinvl, the Guardian style guide doesn't seem to even mention 'kilo', let alone prohibit it. Indeed a quick Google of the Guardian site reveals that they do use it, and extensively. OTOH, it does prohibit any abbreviation, symbol or shortening of "metres". -- de Facto (talk). 10:24, 6 November 2011 (UTC)


 * DeFacto, The Guardian doesn't mention "Fred" either as an alternative to "kilogram". If your logic is correct, it woudl be appropriate for Gaurdian journalists to write about "2 freds of carrots". On a more serious note, the word "kilo" is also used for the kilometre cycle race.  Also, under the Weights and Measures Act provision is made to write either "kilogram" or "kilogramme", but not "kilo" (would you be talking about a kilogram or a kilometre?) which means that in formal texts, teh word kilo has no status.  For that reason, I am flagging it as informal. Martinvl (talk) 16:41, 6 November 2011 (UTC)


 * Martinvl, you are a master of falacious logic. Is "fred" in the dictionaries as a synonym of "kilogramme"? No. So why would I use it as such? "Kilo" isn't mentioned because there are no guidelines restricting its use, as indeed there aren't for "fred" either - or are you saying the use of "fred" is therefore also prohibited? How do you explain away the usages of "kilo" in the Guardian if it is indeed prohibited? -- de Facto (talk). 17:41, 6 November 2011 (UTC)

Unreferenced notes
I added the template to the article because of the huge volume of unreferenced material in the notes. Does anyone know why so much detail is included in these and what the mechanism is for adding in-line references (or tags such as ) to them? -- de Facto (talk). 20:07, 3 November 2011 (UTC)


 * And I have removed the refimprove flag. You can't embed references within notes. Martinvl (talk) 20:35, 3 November 2011 (UTC)


 * Martinvl, how can you justify this edit then? -- de Facto (talk). 21:10, 3 November 2011 (UTC)


 * Please read my posting above regarding the use of "kilo". Martinvl (talk) 21:14, 3 November 2011 (UTC)


 * That doesn't answer the question - you removed the content I added to the note as "unsourced" and removed the 'improveref' I added because much of the content of most of the notes is unreferenced. Please justify. -- de Facto (talk). 21:23, 3 November 2011 (UTC)


 * Re the unreferenced notes, please see Talk:Kilogram/Archive_6. It was not an accidental omission.LeadSongDog come howl!  18:30, 4 November 2011 (UTC)


 * Following LeadSongDog's observation I intend to remove the "Citation needed" flag and to restore the bit about the various national laboratories using kilogram rather than kilogramme to the notes, but referencing it from the body of the artcile, not the lede, thereby keeping the lede clear of citations, notes etc. Martinvl (talk) 19:04, 4 November 2011 (UTC)


 * I have removed the banner from the article, moving the bit about the national laboratories will follow. I also intend to remove DeFactos "discovery" that the NPL uses "kilogramme" as well as "kilogram". I Googled both words and had two confirmed hits for "kilogramme" - one was a citation to a French language document and the other hit was the document cited by Defacto in which "kilogramme" appeared once and "kilogram" four times. I therefore cannot dismiss the possibility that the single appearance in that document was a typo. Martinvl (talk) 16:07, 5 November 2011 (UTC)


 * You've removed the banner, but without improving the refencing - why? The Wiki policy is very clear about the need for references and that unreferenced content can be removed. I saw that old post that LeadSongDog pointed out, it doesn't excuse the current absence of referencing in the 'notes', or anywhere else. -- de Facto (talk). 17:28, 5 November 2011 (UTC)


 * I've put the banner back as the referencing simply isn't good enough. For example: the first paragraph of the first section, the 'Etymology' section, ends with a 'note' (currently 'note 2') which contains the unreferenced assertion "The spelling kilogram is the modern spelling used by the International Bureau of Weights and Measures (BIPM), the U.S. National Institute of Standards and Technology (NIST), the UK’s National Measurement Office, National Research Council Canada, and Australia’s National Measurement Institute." This needs to be verifiable by the reader - but where do we put the tag? -- de Facto (talk). 18:08, 5 November 2011 (UTC)


 * The point of the tag is to highlight assertions which are likely to be challenged. If someone has a good-faith belief that an assertion needs sourcing then they should tag that assertion. Please note what wp:TC has to say about using a cleanup tag as a "badge of shame", its purpose is to draw editors attention to an issue. As there are already ample watchers of this article and its talkpage to address specific issues, it is not helpful to splatter banners across the article on that account.LeadSongDog  come howl!  04:17, 7 November 2011 (UTC)


 * The only reason I used the cleanup tag is because there are so many apparently unsourced assertions buried in the 'notes', with cannot be tagged - as far as I know, and as already explained above. Or can you suggest a way of tagging each of them? -- de Facto (talk). 07:17, 7 November 2011 (UTC)
 * In short, patiently. Avoid wp:TAGBOMBing of articles that are well written. Identify two or three uncited assertions that you think are the most dubious, most significant, or otherwise most likely to be challenged by a reader. Tag those few. If it isn't obvious, leave an explanation why they are worth challenging either on the talkpage or in a hidden text comment. LeadSongDog come howl!  20:15, 14 November 2011 (UTC)

Abbreviation: kilo
Let's not edit war on this, several RS dictionaries give "kilo" as an abbreviation of kilogram/kilogramme, it is futile to deny it, or to suggest that it isn't allowed. The English language isn't regulated - not in the UK anyway. I don't plan any more reversions for the time being (being mindful of the 3RR rule), so will confine further activity on this to the talkpage for now. -- de Facto (talk). 21:39, 3 November 2011 (UTC)


 * I have reinstated the text from the SI Brochure and added the rationale behind its implementation. The use of the word "kilo" is complex and requires discussion.  Since the lede is required to stand on its own, and it is inappropriate to discuss the use of the word "kilo" in that part of the article, I believe that it should not appear there.  BTW, I removed the citation as there are no citations in the lede of this particular article. Martinvl (talk) 17:31, 4 November 2011 (UTC)


 * The OED says 19th century for Kilo in French. Academie Francaise says 18th. What to do?VsevolodKrolikov (talk) 17:50, 4 November 2011 (UTC)


 * Reword to say that the word was imported into English in the 19th century. Martinvl (talk) 17:58, 4 November 2011 (UTC)


 * Thanks. VsevolodKrolikov (talk) 18:06, 4 November 2011 (UTC)


 * I have removed "kilo" from the first line of the lede as per my earlier posting. — Preceding unsigned comment added by Martinvl (talk • contribs)  16:07:55, 5 November 2011 (UTC)


 * In fact "kilo" is an alternative word for kilogramme/kilogram, rather than an abbreviation, and that fact is supported by reliable sources. I've put it back in the lead with a citation of one of the supporting reliable sources as there has been no logical or acceptable justification given for removing it. -- de Facto (talk). 17:18, 5 November 2011 (UTC)


 * (pedant) Technically it's an abbreviation, but that doesn't impact upon whether it should be in the lede. Its prevalence should. (/pedant). VsevolodKrolikov (talk) 18:09, 5 November 2011 (UTC)


 * Yes, the word appears to have started life in France as an abbreviation (of the French word kilogramme). But the free online Oxford Dictionary defines it as a noun, originating from the French abbreviation. Does that make it an abbreviation too? I'm not sure. We do need a 'prevalence' test though, it might be more common than "kilogramme". -- de Facto (talk). 18:18, 5 November 2011 (UTC)


 * Whether it's an abbreviation or not, whether it's slang or just colloquial (clearly the latter IMO), the fact that kilo is in common use for kilogram is worth noting because a priori kilo is just one of many presyllables used in the metric system, and so kilo could a priori be an abbreviation for kiloton, kilosecond, kilometre etc. But it never is. It always means kilogram. Hans Adler 18:31, 5 November 2011 (UTC)

I have changed the word "abbreviation" to "contraction". The differences between these words are well explained in the relevnt Wikipeida articles, so I will not repeat them here. Given that "kilo" is a contraction and not a synonym, does it have a place in the lede, especially as you have to go into the body of the article to find this out? I think not. Martinvl (talk) 22:34, 5 November 2011 (UTC)
 * Corrected to shortening. Contraction is the loss of internal letters. X "Kil'gram" would be a contraction.VsevolodKrolikov (talk) 00:06, 6 November 2011 (UTC)


 * The "Citation Needed" flag is unneccessary - what might be needed is a better way of drawing to attention that the word "kilo" is not permitted in many instances such at anything that complies with the SI Brochure or anything that complies with the 1985 Weigths and Measures Act. If you have a better word than "informal" please let me know, otherwise the neccessary citations are all in the section Entomolgy. Martinvl (talk) 21:12, 6 November 2011 (UTC)


 * A citation is required to support the assertion that "kilo" is "informal" English, as per WP:VER. It's not defined as that in any dictionary that I've looked in. In the free online Oxford Dictionaries "kilo" is defined as a noun meaning kilogram - mention of "informal". OTOH, "poll tax" is defined as "informal term for community charge", so it does distinguish. What has to comply with the "SI brochure"? Where does the 1985 W&M Act prohibit the use of the word "kilo", and to whom does it apply? -- de Facto (talk). 22:12, 6 November 2011 (UTC)


 * , next time please make at least some effort to look for a source before tagging, especially in a high profile article. LeadSongDog come howl!  03:58, 7 November 2011 (UTC)


 * Thanks for digging those out.
 * However they only apply to the circles to which they are targeted. They don't, for instance, apply to how the term is used outside of North American academia. We should confine that discussion to the etymology section and not clutter the lead with it.
 * Life is too short to search for references for all the unreferenced stuff in Wikipedia. The onus should be on the contributor to source their additions, especially as in this case where it is a controversial addition.
 * -- de Facto (talk). 08:24, 7 November 2011 (UTC)


 * What I meant to say in edit summary: "claimed synonymy &/or "reasoning" that kg is "symbol" for kilo is original research". There's no such *symbol* for such an abbreviation either--JimWae (talk) 08:34, 7 November 2011 (UTC)


 * I'll carry on this discussion in the section I added below. -- de Facto (talk). 08:37, 7 November 2011 (UTC)

Is "kg" also the symbol for "kilo"?
Please discuss here before entering into an edit war. My view is that given that the words "kilogram" and "kilo" are both synonyms of the word "kilogramme", it follows that if "kg" is the symbol for "kilogramme", it is also the symbol for "kilogram" and "kilo". For that reason the beginning of the lead sentence "The kilogram, kilogramme or kilo (symbol: kg) is the base unit of mass in the..." is correct. -- de Facto (talk). 08:34, 7 November 2011 (UTC)


 * Do you have a source saying kilo has ANY symbol at all (other than "k" for kilo-, that is)? --JimWae (talk) 08:38, 7 November 2011 (UTC)


 * As 'kilo' is a synonym of 'kilogramme', isn't it fair (and common sense) to say that as 'kg' is the symbol for kilogramme that it is also the symbol for kilo? Even if we were to agree that, actually, it isn't, then 'kilo' still shouldn't be eradicated from the lead as it is still a synonym. Rather the lead should be reworded to accommodate it (e.g. "The kilogram or kilogramme (symbol: kg), also known as kilo, is the..."). -- de Facto (talk). 08:49, 7 November 2011 (UTC)


 * "kg" is the internationally recorgnised symbol for kilograms just as "km" is the intenationally recognised symbol for kilometres (See Chinese roadsign to the right). In terms of UK law (Weights and Measures Act 1985), "kilo" is not a synonym for "kilogram" because it cannot replace "kilogram" in legal texts. This headline (Chris Hoy's kilo record falls to power-packed German Stefan Nimke) has nothing to do with kilograms at all which is why the word "kilo" cannot be used in official texts. Martinvl (talk) 09:03, 7 November 2011 (UTC)


 * Who is talking "official" or UK law? This is an article on Wikipedia, not the text of a pseudo-law from the SI. Have you looked at the definitions in the English dictionaries cited or looked up common usage on Google, in the Guardian etc. Open your eyes - you see ample evidence that 'kilo' is used interchangably with 'kilogramme'. That's not the discussion this time, however - that is already known. The question here is, given that 'kilo' is used as a synonym of 'kilogramme', is it fair to say that the symbol 'kg' applies to it too? -- de Facto (talk). 09:12, 7 November 2011 (UTC)


 * Do you have a source saying kilo has ANY symbol at all (other than "k" for kilo-, that is)? The present lede does already accomodate "kilo", as an informal term, which it is--JimWae (talk) 09:16, 7 November 2011 (UTC)


 * It is only considered to be informal by those in certain academic circles. The regular dictionaries, including those that use the word "informal" in definitions of informal words or phrases, give it as a synonym (and don't declare it to be informal). -- de Facto (talk). 09:23, 7 November 2011 (UTC)


 * To answer the other point (again): as 'kilo' is a synonym of 'kilogramme', isn't it fair (and common sense) to say that as 'kg' is the symbol for kilogramme that it is also the symbol for kilo? -- de Facto (talk). 09:25, 7 November 2011 (UTC)


 * I do not accept it as "given" that kilo and kilogram are complete synonyms either - though I see that as a premise for your argument. Arguments generally appear to be WP:OR, especially absent a source for kilo having any symbol at all. --JimWae (talk) 09:27, 7 November 2011 (UTC)


 * Fair enough; I'll leave it there then - we disagree. -- de Facto (talk). 09:30, 7 November 2011 (UTC)

I do not see that you have made a case for dropping the notation that "kilo" is informal. That has been sourced. --JimWae (talk) 09:33, 7 November 2011 (UTC)


 * The "sourcing" that you refer to only applies to certain academic/technical circles. Oxford dictionaries, that include "informal" in the definition if it is appropriate, do not define 'kilo' in such terms. To assert that it is indeed generically "informal" would be OR in the circumstances, and neither of us would tolerate that - would we? -- de Facto (talk). 09:43, 7 November 2011 (UTC)


 * Kilo is clearly an alternative shortening of kilogram with widespread usage, and not just conversationally. It appears in formal, non-scientific texts - for example The Economist explicitly allows it in their stylebook (convenience link here) while deprecating kilogramme. However, it's pretty clear from looking at style guides such as Nature that science and technical authors are supposed to adhere strictly to the SI nomenclature. We also have the Canadian government website explicitly advising against it in technical writing. This is too complex to go into in the lede, but would certainly be appropriate in the etymology section, which could be renamed "etymology and use".
 * "In the 19th century the French word "kilo", a shortening of "kilogramme", was imported into the English language and is also used to mean kilogram. While often acceptable in generalist texts (cite economist as example?) its use is typically considered inappropriate in scientific and technical writing, where authors should adhere strictly to SI nomenclature."cite Canadian gov, cite Nature guide (which says "Units should have a single space between the number and the unit, and follow SI nomenclature (for example, ms rather than msec) or the nomenclature common to a particular field.")
 * If I may be pedantic again, kilo is not a perfect synonym for kilogram, because there is no such thing as perfect synonymy. Kg is not a perfect synonym for kilogram either, for that matter. (There are times when we would use one but not the other). People need to take as much loving care with linguistic terms as with SI ones ;-).VsevolodKrolikov (talk) 10:27, 7 November 2011 (UTC)


 * VsevolodKrolikov's proposal looks reasonable - I would however want to restore the word "informal" into the lede: we need sonmething in the lede to clarify that "kilo" is not acceptable in all circles - the word "informal" is the best I have seen to date. I would also like the appropriate sentence to read "... its use is considered inappropriate in certain applications including scientific, technical and legal writing, ...". The inclusion of the word "legal" is implied by the UK Weights and Measures Act 1985. Martinvl (talk) 10:56, 7 November 2011 (UTC)


 * Martinvl, as it is only considered to be "informal" in some circles any use of the word "informal" in the lead would need to be appropriately qualified there. That would lead to "lead-clutter". It is best to discuss the specific exceptions to general use in the etymology section. -- de Facto (talk). 11:09, 7 November 2011 (UTC)


 * VsevolodKrolikov, that looks good to me. Keep the specific details in the sub-section and the general case in the lead. -- de Facto (talk). 11:06, 7 November 2011 (UTC)


 * It is a requirement that the lede shoudl be stand-alone. I agree that a concise definition of the status of the word "kilo" would result in lead-clutter, but we MUST have something, if only to protect a schoolchild from getting marked down by the science teacher for using the word "kilo" inappropriately.  I favour the inclusion of teh word "informal".  Can yo ucome up with anything better? Martinvl (talk) 11:16, 7 November 2011 (UTC)


 * Wikipedia isn't a school science textbook. 'Kilo' isn't "informal" in English language for example, so why emphasise just the academic scientist view of the word? An alternative word isn't required in the lead - it is correct without it. -- de Facto (talk). 11:28, 7 November 2011 (UTC)


 * Would you be happy with the word "colloquial". Another alternative is to removed references to the word "kilo" in the first sentence and to add the sentence "In some contexts the shortened form kilo is used." to the end of the first paragraph. Martinvl (talk) 15:21, 7 November 2011 (UTC)


 * It's important not to throw these terms around so loosely. Colloquialism has a specific meaning, and no dictionary I have found calls "kilo" a colloqualism - or even informal (that Canadian site is good for science writing not using "kilo", but it's not where I'd go for more general lexicography). I'm not surprised, given how easy it is to find "kilo" in many typically "formal" texts, as well as informal. We'd need a proper authority, such as a well-respected dictionary, or possibly a rather major publication style guide for such a strong statement in the lede, and I doubt we'd find one. I'm having a look for sources that proscribe/permit kilo in legal texts (such as legal journals) - I haven't found anything yet. As it stands we can't use interpretations from lacunae in one law in one country to make such general statements about legal texts.
 * As for "some contexts", the opposite is true. As far as anyone has shown, it's only in some contexts (science publications) that "kilo" is not acceptable. As for your specific concern: it's in a specific context, which is a student who needs to go to wikipedia for his main source of what kilo is, with (and I use professional jargon here) an arse for a science teacher who believes in aggressively penalising students for something he's neglected to teach them in the first place. We can't really legislate for every circumstance. In any case, even some GCSE maths textbooks (by serious authors and publishers) will occasionally use "kilos", so I'm not convinced it's a big problem anyway.
 * It would be wrong to downplay the word kilo as something that only appears occasionally, because that wouldn't reflect actual usage. The British National Corpus suggests it's used more frequently (152 results) than kilogram (68) and kilogramme (24) combined. American Corpus of Contemporary English shows kilogram (279) and kilo (273) used about as often as each other. I appreciate it's deprecated in science publications, and that's what I suggest we state in the etymology/use section. But these concerns shouldn't be allowed to force misrepresentations how kilograms are referred to in general usage.VsevolodKrolikov (talk) 16:32, 7 November 2011 (UTC)
 * The British National Corpus does not distinguish between language that is usually acceptable and language that is usually unacceptable. I tested it with the word "fuck".  That word is usually not acceptable in Wikipedia except in circumstances like this. If the British National Corpus is unable to tell me which words are unacceptable in polite company and which are not, it is no guide to what word are acceptable formal as opposed to informal writing - it is merely a counting tool. Martinvl (talk) 16:49, 7 November 2011 (UTC)


 * I didn't say the BNC provided evidence of formal register per se (that would involve far more complex analysis). The corpora show that the word is used very widely and should not be dismissed as some occasional event.  For register we should defer to acknowledged scholarly and style authorities. (That a balanced database of English usage contains "fuck" should only cause concern to prudes.) VsevolodKrolikov (talk) 17:12, 7 November 2011 (UTC)

Disregarding for the moment the specific term of linguistics to apply, it should be clear to anyone that kilo is not the primary term, but rather a derived one. Dictionaries give their full definitions under kilogram, and then under kilo will refer to that rather than provide a definition. Reaching for my Concise Oxford dictionary 7th ed I find "kilo n. (pl. ~s). kilogram; kilometre. [F, abbr.]" "kilogram, -gramme n. unit of mass or weight in the metric system, equal to that of the international prototype kept at Sevres near Paris, approx. 2.205 lb."

Does anyone suggest citing a RS that does the reverse? LeadSongDog come howl!  17:44, 7 November 2011 (UTC)


 * Of course no one is suggesting retitling the article. It's a question of whether we say in the lede that it's also often referred to as "kilo", or whether we treat "kilo" as some kind of shameful family secret to be revealed to prospective spouses only at the appropriate time. I can't see anything particularly wrong with the lede as it is right now, although a tweak to often referred to as "kilo"  might be more acceptable to parties here. We don't need to go inventing usage descriptions that aren't supported by proper RS, and we shouldn't have one particular genre or field dictate the lede. The primary topic is not Kilogram (science writing).
 * I know you want to put terminology aside, but it's not actually a derivation of kilogram (derivations are where the syntactic category changes, such as grammar -> grammatical). It's a shortening/clipping imported from French. (It wasn't shortened in English - which I think is quite interesting.) As such, it's an alternative name. (We deal with the different register of "kilo" in the main body.) We shouldn't give the impression that it's somehow generally faulty or slang to call a kilogram a kilo, as that's patently not the case. Compared to kilogram it's more informal, but that's not the same as it being a word only appropriate for informal contexts.VsevolodKrolikov (talk) 01:57, 8 November 2011 (UTC)
 * Of course it isn't a shameful secret, but we have at least two wp:RS which call the usage "informal" and none that contradict them. Just as we would not use the word "plane" without disambiguation to mean airplane, aeroplane, or aircraft, neither should we use the ambiguous and informal "kilo" in lieu of the unambiguous kilogram. The arguments from the Corpus of Contemporary American English don't seem to be very carefully made, as the given count of 273 instances includes many of "Kilo Company", "Kilo Submarine", the ship "Kilo Moana", the Addis Ababa landmark "Arat Kilo", a person "Meio Kilo", a person "Yong Kilo", a backpacking equipment brand name "Sub Kilo", and of course "kilo gram" (such as might be seen at a line break). Many of the remaining instances of "a kilo" or "kilo of" were used in specific references to illicit drugs or to groceries in foreign contexts. LeadSongDog come howl!  19:53, 9 November 2011 (UTC)
 * VsevolodKrolikov wrote "Compared to kilogram it's more informal, but that's not the same as it being a word only appropriate for informal contexts." According to teh Oxford Concise Dictionary, one of teh definitions of the word "formal" is "Valid in virtue of its form, explicit and definite". The word "kilo" cannot be said to be "explicit" - after all it could mean either "kilogram" or "kilometre"; therefore it is not used in formal speech. Martinvl (talk) 21:52, 9 November 2011 (UTC)
 * "Informal" does not mean bad, nor even substandard, nor slang. It means it is entirely accepted in less formal writing and speech, but, in formal circumstances, the more formal form is completely acceptable.--JimWae (talk) 00:28, 10 November 2011 (UTC)
 * That's not quite right. Designating a word "informal" does not only mean it is accepted in informal circumstances. It means that it is not acceptable in formal contexts. This is not true of the word "kilo" - it is considered inappropriate (ie to be avoided) in science and technical writing contexts, but is obviously acceptable in other non-informal circumstances - as shown by wide attestation in highbrow news articles and non-science academic contexts. The source we have for it being "informal" is a translation site for technical translations between French and English. It's not a terrible source (it suffices for as one of the sources for Kilo being inappropriate in technical writing), but for the use of words in general we have so much better ones. In addition to what we can see for ourselves by looking at newspaper and non-science academic books, in dictionaries which commonly list terms as "informal" if they are, "kilo" is not listed as informal (for example, terms like "K" for thousands in money, are usually listed as informal); general manuals of style do not list the word as one to be avoided for reasons of informality (one approves the use). Finding a single source that goes against all this to support a point of view (especially for the weasel phrase "in some circles") isn't really the way we do should do things here. It is better that we don't say things which have a fair chance of being inaccurate, and instead stick with what's clearly the case, which is that we don't use kilo in technical writing. I suspect clarity is more important (kilo or kilo-?) in this embargo than register.VsevolodKrolikov (talk) 03:18, 10 November 2011 (UTC)


 * What is meant by "technical writing"? Anything with numbers? Many manuals of style cover themselves by requiring that the conventions used in the SI Brochure be followed.  Also, in order to keep them down to a reasonable size, manuals of style tend to concentrate on matters that are most likely to affect their own journalists, editors and writers. There are huge gaps in most manuals of style - one that I always look for is to see how they handle the difference between "mW" and "MW" - not many comment on this difference (which is significant), so one cannot assume that the manual covers all cases. Martinvl (talk) 07:47, 10 November 2011 (UTC)

A few definitions of "formal" in the Oxford Concise Dictionary include: WOudl somebody please tell me which about any "formal" applications they know of where "kilo" is acceptable which also meets the above definitions (or are there some defintions that I have left out?). Martinvl (talk) 21:10, 12 November 2011 (UTC)
 * "Explicit and definite, not merely tacit"
 * "Having the form without the spirit"
 * "Observant of forms"
 * "Precise"
 * "Excessively regular or symmetrical"
 * "Methodical"


 * Sorry, I'm having trouble parsing that. Can you rephrase the request please. -- de Facto (talk). 22:47, 12 November 2011 (UTC)


 * Martinvl, have you ever heard of a field of study called lexicography? It's rather unfashionable these days to defer to experts, but if I were looking for what "informal" meant when talking about word usage, that's the area I'd look at first. In "Lexicography: an introduction" the author cites with approval the Longman Dictionary of the English Language:
 * The label informal is used for words or meanings characteristic of conversation or casual writing (eg. between friends and contemporaries) rather than formal or official speech or writing.
 * That is, informal words generally do not appear in writing other than in familiar communication. The presence of a more formal equivalent is not a determinant of informality. Infant is more formal than child, but child is not informal. ("Kid" is arguably informal.) The context in which a word occurs determines judgement of its register. Informal words typically have non-informal counterparts, but their status as formal or informal is independent of the existence of other words.
 * Also note that there are therefore lots of words which are neither classed as "informal" or "formal". These are often referred to as "unmarked" (ie the lexicographer makes no note of the register in a dictionary entry). As it's possible to confirm very easily, kilo appears in non-familiar written communication rather a lot. We should not be surprised at all that lexicographers do not consider the word informal.
 * I hope this answers your question, and that you now understand why your addition to the lede was faulty. The terminology used in dictionaries is applied with established meanings. It's very important not to go reinventing whole areas of study simply because you're unfamiliar with them.VsevolodKrolikov (talk) 05:15, 13 November 2011 (UTC)


 * I do not agree with your comments - for a start you wrote "Infant is more formal than child, but child is not informal". This is incorrect - "infant" and "child" are two different words - is there a more formal way of writing "My eldest child is an army officer" if one does not wish to disclose the sex of the child? I would hardly call such a person an "infant". I think that you are clutching at straws here - in practice each publication can decided for itself how formal or informal it wishes to be and in what circumstances it wil permit informality - the Economist for example appears to be happy to use the word "kilo", but probably not "kid" whereas the tabloids are quiet happy to use the same word to describe children as they would use to describe young goats. Legal texts of course do not (or maybe should not) use any informal language (at least that is my understadning) as this could lead to misunderstandings. Again, back to the Concise Oxford Dictionary definitions above - in particular "kilogram" is "Explicit and definite" whereas "kilo" is "tacit" ("kilo" is also used as a shorthand for "kilometre"). Martinvl (talk) 17:44, 14 November 2011 (UTC)


 * You appear to miss the point of the citation from the book on lexicography. I can't emphasise enough the important of not ignoring a whole, long-established field of research. It's even worse if people have told you to take it into consideration and then you still ignore it. This is an encyclopedia, not some talkboard where people can sound off about their gripes.VsevolodKrolikov (talk) 17:53, 14 November 2011 (UTC)


 * On the contrary, you are the one who has missed the point by failing to see that there are degrees of informality - how much longer will you go on with this stupid assertion the word "kilo" should not be flagged with the word "informal" in the lede and at the same time doing absolutely nothing positive to indicate to the reader that there are circumstances where "kilo" should not be used ... and don't tell me that it is all in the article; the lede should be a stand-alone piece of text, complete in its own right. Furthermore what source have stated that "kilo" an be used in formal language - the only one that I have found was the US Act of 1868 and that has been revoked. Martinvl (talk) 18:27, 14 November 2011 (UTC)


 * It's fine that you think lexicography is stupid. On the other hand, it's really quite important that wikipedia doesn't reflect that opinion. VsevolodKrolikov (talk) 18:34, 14 November 2011 (UTC)


 * Martinvl, as has been shown and explained above why it is not  "informal" - so to assert it as such in the lead would be incorrect. Discuss where its use isn't appropriate in the appropriate section - but don't ignore the fact that "kilo" is a synonym for kilogramme outside of certain regulated uses. -- de Facto (talk). 18:40, 14 November 2011 (UTC)


 * No DeFacto - you have obviously not read my rationale, or if you did, you either did not understand it or you have chosen to ignore it. On reading VsevolodKrolikov's explanation (which by way of his example of child/infant is incorrect anyway) I get the feeling that he sees things in black and white: communications being either "formal" or "informal" - I see things in shades of gray - communications have degrees of formality - some elements being formal and others informal. Please read my last posting. Martinvl (talk) 21:09, 14 November 2011 (UTC)


 * Martinvl, your arguments are inconsistent. It is precisely because there are shades of grey that you can't assert "kilo" to be only informal. Think of it as informal=black and formal=white. If "kilo" is grey, it's incorrect to assert it as white - isn't it?


 * As for VsevolodKrolikov's analogy - "child" is a less precise word than "infant" for a very young child. That doesn't imply that "child" is an informal word, or that "infant" is a more formal word for every use of "child". -- de Facto (talk). 22:19, 14 November 2011 (UTC)

Can we conclude then that:
 * As kilogram = kilogramme
 * And as kilogramme = kilo
 * And as kilogram = kg
 * That therefore kilo = kg?

-- de Facto (talk). 09:14, 16 November 2011 (UTC)


 * Of course not. We cannot say "kilogram = kilogramme", as the former spelling is international and avoids the specific BrEng application of the latter (the ..mme spelling would be jarring in an AmEng article). Nor can we say "kilogramme = kilo", since the former is unambiguously a mass equal to the IPK while the latter has plural meanings. Even to say "kilogram = kg" confuses the unit with the symbol for that unit. LeadSongDog come howl!  15:20, 16 November 2011 (UTC)


 * Let me put it another way for you LeadSongDog...
 * As when the word "kilogramme" is used it implies "kilogram"
 * And as when the word "kilo" is used in certain contexts it implies "kilogramme" (e.g. a kilo of apples)
 * And as when the symbol "kg" is used it implies "kilogram"
 * That therefore when the symbol "kg" is used it could also be interpretted as "kilo" (e.g. "1 kg of apples" could reasonably be read as "one kilo of apples")
 * -- de Facto (talk). 16:25, 16 November 2011 (UTC)


 * I'm not really sure what DeFacto means. On the one hand, all of those terms noncontroversially refer to the same thing, but on the other hand, as LeadSongDog correctly observes, they do not share the same register. If we're speaking in terms of article content, the current content seems fine: the lede notes the different terms, and the etymology section deals with the variation in usage - which reminds me to go and change the title of that section to "etymology and usage".VsevolodKrolikov (talk) 15:48, 16 November 2011 (UTC)


 * I'm trying to understand whether "kg" can also be considered to be the symbol for "kilo" when "kilo" is being used as a synonym of kilogram (the reason I started this thread). I'm exploring this because I think that the lead should read: "The kilogram, kilogramme or kilo (symbol: kg)..." rather than the current, less elegant: "The kilogram or kilogramme (symbol: kg), also known as the kilo...". -- de Facto (talk). 16:11, 16 November 2011 (UTC)
 * I prefer the lede as it is now. Kilogram and (to a lesser extent) kilogramme have official status, which in an encyclopedia should be given precedence. Kilo, while by no means being an informal term, does not share that privilege.VsevolodKrolikov (talk) 16:20, 16 November 2011 (UTC)


 * "Kilo" only has a symbol when it is a unit prefix (as in kg, km, kN, kJ, kW etc) and then the symbol is "k". This is laid down by the CGPM. Martinvl (talk) 17:48, 16 November 2011 (UTC)


 * Martinvl, that implies that the perfectly legitimate phrase: "0.454 kilos of strawberries" cannot be written as "0.454 kg of strawberries". Is that really true? -- de Facto (talk). 18:24, 16 November 2011 (UTC)


 * The symbol "kg" doesn't stand for the word "kilogram", it stands for the concept behind that word. The word "kilo" stands in for multiple concepts, only one of which is associated with the symbol "kg". No one would use the symbol "kg" for K|the eleventh letter of the English alphabet, for a boat or for a place, but people do use kilo to mean exactly those things. This lack of rigour is in fact characteristic of informal language. Because informal language is conversational (or used in written portrayals of dialog) this ambiguity is accepted: any confusion can readily be sorted by Q&A. The same police officer who succinctly tells his partner "Smith had three kilos of coke in his trunk when I stopped him" might write in his report or state in his testimony that "Upon searching the vehicle which Mr. Smith was driving, I found three packages in the trunk, each of which I logged into evidence. Each package was later confirmed by forensic analysis to contain approximately one kilogram of cocaine." Such formalism is largely intended to ensure that a record or communication is unambiguous to any reader (although diplomatic formalism can have different objectives). LeadSongDog come howl!  18:26, 16 November 2011 (UTC)
 * The symbol "kg" doesn't stand for the word "kilogram", it stands for the concept behind that word. The word "kilo" stands in for multiple concepts, only one of which is associated with the symbol "kg". No one would use the symbol "kg" for K|the eleventh letter of the English alphabet, for a boat or for a place, but people do use kilo to mean exactly those things. This lack of rigour is in fact characteristic of informal language. Because informal language is conversational (or used in written portrayals of dialog) this ambiguity is accepted: any confusion can readily be sorted by Q&A. The same police officer who succinctly tells his partner "Smith had three kilos of coke in his trunk when I stopped him" might write in his report or state in his testimony that "Upon searching the vehicle which Mr. Smith was driving, I found three packages in the trunk, each of which I logged into evidence. Each package was later confirmed by forensic analysis to contain approximately one kilogram of cocaine." Such formalism is largely intended to ensure that a record or communication is unambiguous to any reader (although diplomatic formalism can have different objectives). LeadSongDog come howl!  18:26, 16 November 2011 (UTC)


 * LeadSongDog, your "logic" works equally for the argument that "g" cannot be the symbol for "gram" because gram stands for multiple concepts too. -- de Facto (talk). 18:44, 16 November 2011 (UTC)


 * You may be beginning to understand, but you still haven't quite got it. A symbol and a word are not the same as the concept they represent. The symbol "g" has multiple associated concepts. In SI it stands for the concept of the derived unit denoted by the word "gram", while in the cgs system of units it stood for the quite different concept of the base unit denoted by the same word "gram". In pure physics it stands for the concept "acceleration due to mean terrestrial sea-level gravity", and in applied physics it stands for a specific numeric value of that pure physics concept. Our manual of style is clear that when we use kg without special qualifiers we mean the SI kilogram, not a thousand cgs grams, nor an acceleration of magnitude 32000 feet/second/second. Editors of encyclopedic text should strive to be unambiguous so far as possible. LeadSongDog come howl!  19:38, 16 November 2011 (UTC)


 * You have clarified that, in the context of this article, the kilogram[me] represented by the use of the word "kilo" (which is the same concept as the kilogram[me] represented by the words "kilogram" or "kilogramme") can be represented by the symbol "kg". -- de Facto (talk). 20:51, 16 November 2011 (UTC)

You have missed an important point - within the SI system, "kg" is the symbol for "kilogram[me]", but the SI system does not permit abbreviations for unit names and the name "kilo" is designated as a prefix. This article cannot rewrite the rules - that is WP:OR (promoting a novel concept), so unless you can find a reliable source that explicitly states that "kg" is the symbol for "kilo", I am afraid that we cannot make such a statement. BTW, you would do well to read the article metric system, not with the object of faulting it, but with the object of learning from it. Martinvl (talk) 21:08, 16 November 2011 (UTC)


 * Martinvl, this is an article about the kilogramme. The SI view is just one of many views of the subject matter. We cannot allow the article to be hijacked and used to promote just one position on this - we need to achive a balanced POV. The "kg" symbol represents the thing whether we call it a kilo or kilogramme - no matter what the SI may want us to believe. -- de Facto (talk). 22:53, 16 November 2011 (UTC)

For what it's worth, I like the current "The kilogram or kilogramme (symbol: kg), also known as the kilo..." more than I like the proposed alternative "The kilogram, kilogramme or kilo (symbol: kg)...". I would not call either of them "incorrect", but the first one (as I read it) has a subtle insinuation that "kilo" might not be appropriate to use in every context, which is a nice and correct insinuation. They are about equally easy to read and understand: I don't particularly mind that there are a few extra words in the first one. I think both alternatives are good enough to use, especially given the thorough explanation in the etymology section. Much else in the article is more deserving of attention than this! --Steve (talk) 22:09, 16 November 2011 (UTC)


 * Steve, I tend to agree with you, although I'm slightly uncomfortable with the way the article is being biased towards an elitist interpretation of the subject matter. And yes, there are certainly more important things to worry about! -- de Facto (talk). 22:46, 16 November 2011 (UTC)


 * DeFacto seems to forget that the definitive kilogram is in the custody of the BIPM under the authority of the CGPM - it is they who define what a kilogram is and how it should be used. The name given to it is just like a person's name.  I notice that Steve chooses to sign himself as "Steve", though his birth certificate might give his name formally as "Stephen" or "Steven".  That is his choice.  Other people with the same name might not like having their name shortened.  Again that is their choice.  The same goes with the custodians of the kilogram - it is their preogative to indicate how the object over which they have custody should be named and in 1960 they stated firstly that "kilo" was a prefix and secondly that "abbreviations" should not be used for unit names. (The word "abbreviation" is an approximation to the equivalnetbn French text).  For formal purposesd their wishes should be respected. Martinvl (talk) 07:52, 17 November 2011 (UTC)


 * Martinvl, that is the POV that I alluded to above. However, I'm not arguing that there isn't a standard, widely adopted and largely enforced, for how big a kilo is. The problem, as I see it, is the pushing of the POV (and the attempts to erase all other views) that in "real life" the SI doctrine is somehow pre-eminent and no-one, anywhere, deviates from it. That is demonstrably untrue. There is no reason not to have a small section describing the SI view, but it should be kept to that, and not dominate and permeate the whole article, and the lead should, neutrally reflect the real-world kilogramme - not just an idealised interpretation of the output from one organisation. See WP:NPOV. -- de Facto (talk). 08:24, 17 November 2011 (UTC)


 * On the contrary. If you go to a trader's stall and challenge his interpretation of the kilogram he is able (or at least in law shoudl be able) to produce a certificate that his weighing device has been calibrated against a specific kilogram weight that has a known tolerance. That weight would in turn have been calibrated against one that has a tighter tolerance and so on up to the one which is kept in the NPL (or other national) laboratories under tightly controlled conditions. The weight at the NPL (as is every other national prototype)is in turn calibrated against the prototype held at the BIPM headquarters at regular intervals (about every 25 years). In this way, if you specify a mass in kilograms and somebody in a differenrt country picks up your specification, they will be able to understand what you mean to the same precision that is available to your next-door neighbour.  (This is to avoid the sort of mess that we have with the fluid ounce and pint - in the UK there are 20 fluid ounces to the pint, in the US, there are 16).   The real problem I think is that DeFacto is naïeve about what happens behind the scenes - without SI, the kilogram is a meaningless concept. Martinvl (talk) 09:49, 17 November 2011 (UTC)


 * Did you read what I wrote? I understand calibration and certification - I even stated above that the standard was: "widely adopted and largely enforced, for how big a kilo is". What I have an issue with, and what you have failed to address, is the biased POV presented with regard to real-world adherence to the "style" aspects: including jargon, terminology, etc. of the SI output. There is nothing stopping most people calling it what they like and writing it how they like - and they do. That they may choose to call it a "kilo" doesn't mean they can't use the "kg" abbreviation (what the SI define as the "symbol"). -- de Facto (talk). 10:05, 17 November 2011 (UTC)

Does anyone see any source saying kilo has ANY symbol at all (other than "k" for kilo-, that is)? Kilo is already a less formal shortening of the full term. Arguments generally appear to be WP:OR, especially absent a source for kilo having any symbol at all. JimWae (talk) 10:28, 17 November 2011 (UTC)


 * I agree with JimWae. The evidence to date shows the formal use of "kilo" to be historic (ie before the introduction of SI half a century ago). Martinvl (talk) 10:31, 17 November 2011 (UTC)


 * Martinvl, why artificially, and flying in the face of WP:NPOV, limit the scope of the article to just "formal" use? -- de Facto (talk). 12:29, 17 November 2011 (UTC)


 * JimWae, do you believe that "kg" is the symbol for:
 * a) the word "kilogram"
 * b) as LeadSongDog asserts above, for the concept behind the word?
 * -- de Facto (talk). 12:25, 17 November 2011 (UTC)


 * To save JimWae the bother, the answers can be found here. Martinvl (talk) 15:48, 17 November 2011 (UTC)


 * Martinvl, to save us all the bother of reading the eighty-odd pages of that, can you tell us the answer, and which page number it is on please. -- de Facto (talk). 16:08, 17 November 2011 (UTC)


 * The references are given in the main article. That is one of the purposes of an encyclopeadia. Martinvl (talk) 16:14, 17 November 2011 (UTC)


 * Martinvl, I can't find it. If you think you know the answer, please give it (and the page number in the brochure) here please. -- de Facto (talk). 16:40, 17 November 2011 (UTC)


 * I suggest that you read pages 130 and 131. They explain how symbols are constructed and why the symbol for "kilogram" is "kg". Now a question for Defacto - what exatly do you mean by the "concept behind the word"? If you mean "kilogram" as written in other languagers, then "yes", but the word "kilo" is and remain a prefix which in formal documents is used in conjunction with units of measure, not on its own. Martinvl (talk) 17:20, 17 November 2011 (UTC)


 * Thanks for that Martinvl. I found how the SI define a "unit symbol" - as a "mathematical entity" (p130, s5.1). So I was correct and you were, err, not. The mathematical entity represented by the unit symbol "kg" is, as I suspected, the thing that is referred to using various words such as: kilogram, kilogramme, Kilu, Cilogram, Chilogrammo, Quilograma, kilo, etc. So with the support of the SI brochure, no less, I propose that the lead should be modified to the following: "The kilogram or kilogramme, also known as the kilo (SI unit symbol: kg)...". This accommodates the need to distinguish "kilo" as an "also ran" and clarifies what "symbol" exactly. Any comments before I make the change? -- de Facto (talk). 19:17, 17 November 2011 (UTC)


 * I've now changed it as per this unchallenged proposal. -- de Facto (talk). 23:07, 18 November 2011 (UTC)


 * I checked the usage of "kilo" in the OED - they only gave two examples, both in the 1880's. In response to DeFacto's suggestion that I am "flying in the face of WP:NPOV, limit the scope of the article to just "formal" use?" - I am not - though I am clarifying what is formal and what is informal - sonmething that an encyclopeadia should do. Martinvl (talk) 16:00, 17 November 2011 (UTC)


 * Martinvl, what do you surmise the significance of the dates of the OED examples to be? -- de Facto (talk). 17:55, 17 November 2011 (UTC)


 * The OED has not given any qualification as to the use of the word "kilo". Thsi suggests that is ceased being used in formally in the 1880's.  The OED cites "kilo" as an abbreviation of "kilogram".  The OED entry for "kilogram" makes no mention of the word "kilo" (except as a prefix), but it does mention "chiliogramme" as an alternative form that has been used in the past (in 1825!).  Therefore, in the eyes of the OED, "kilo" is an abbreviation for "kilogram" and since 1960 the CGPM has not permitted abbreviations, it has no place in formal usage.  It is therefore an informal version of "kilogram". Martinvl (talk) 20:22, 17 November 2011 (UTC)


 * Let's now look at the OED entry for "kg". It gives only one example - and that's from from 1892. It gives no qualification as to its use. Does this suggest to you that it ceased being used formally in the 1890s? The entry for "kilogram" makes no mention of "kg" at all. Martinvl, based on its obvious similarities with "kilo", "in the eyes of the OED", will you now be attempting to expunge all mention of "kg" from the article? -- de Facto (talk). 20:49, 17 November 2011 (UTC)


 * The OED entry for "kg.", taken from the Pall Mall Gazette in 1892, shows "kilogram" under "Quotations: First in sense" in the OED. The entry says nothing about ongoing usage and shows no different sense introduced at any later date. LeadSongDog come howl!  21:13, 17 November 2011 (UTC)


 * Yes, and the entry for "kilo"...? -- de Facto (talk). 21:22, 17 November 2011 (UTC)

So also, no new meaning introduced since 1887 for "kilo".
 * "1870  Daily News 2 Dec., They provide the bread at 35 cent. a kilo, the same price as‥in Belgium. 1887    C. A. Moloney Sketch Forestry W. Afr. 77  The price for each hundred kilos of oil produced‥varies according to the pressures."


 * Exactly. You'll agree then that Martinvl's assertion that "kilo" hasn't been used since the 1880s is flawed. -- de Facto (talk). 23:35, 18 November 2011 (UTC)

I am one of the page watchers here, and every dozen hours or so I have made the mistake of looking at this discussion. But now I am tired. Can someone wake me up once you have come up with a definite number? Good night. (Oh, and if you are heading for WP:LAME, you will have to start edit warring at some point.) Hans Adler 23:39, 18 November 2011 (UTC)

Convenience break
1> There is no "(SI unit symbol: kg)" for kilo AND 2> the placement of the commas in "The kilogram or kilogramme, also known as the kilo (SI unit symbol: kg)," makes it appear as if the symbol is linked ONLY to kilo, 3> at least 3 editors have already opposed that version --JimWae (talk) 23:41, 18 November 2011 (UTC)


 * 1) The SI unit symbol is for the thing that is known in English as kilogramme, kilogram or kilo. The SI's English text only mentions "kilogram", but so what? Yes, I know "kilo" has other meanings too, but the context usually clarifies which meaning is intended - this is common in the English language (gram, meter, second and mole are such words too). 2) (Re)move the comma to clarify that then. 3) It hasn't been opposed on the talkpage since I proposed that particular wording, with the support of the SI brochure. The previous wording might have been opposed. -- de Facto (talk). 00:00, 19 November 2011 (UTC)


 * Where in the SI brochure is the use of the word "kilo" as a substitute for "kilogram" supported. As far as I am concerend, since 1960 the use of the word "kilo" as a substitute for "kilogram" has an informal status. Martinvl (talk) 09:46, 19 November 2011 (UTC)

Which of these sentences is accurate and true: ? In "also known as the kilo", we are talking about the word "kilo" not about the concept of the kilogram - and it should probably be marked in italics or quotes--JimWae (talk) 10:09, 19 November 2011 (UTC) It is even worse for "kilo" when we restore (symbol: kg) to (SI symbol: kg) --JimWae (talk) 10:12, 19 November 2011 (UTC)
 * The kilogram (symbol: kg) is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.
 * The kilogramme (symbol: kg) is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.
 * The kilo (symbol: kg) is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.
 * The kilo (symbol: kg) is a term for the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.
 * The kilo (symbol: kg) is another term for the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.
 * "Kilo" is a less-formal term for the base unit of mass in the International System of Units, the kilogram, WHICH is defined as being equal to the mass of the International Prototype Kilogram (IPK), AND is almost exactly equal to the mass of one liter of water.
 * "Kilo" is a colloquial or less-formal term for the base unit of mass in the International System of Units, the kilogram, WHICH is defined as being equal to the mass of the International Prototype Kilogram (IPK), AND is almost exactly equal to the mass of one liter of water.

I'd say "kilo" for kilogram has about the same acceptance in semi-formal writing as "K" does for kilometre, slightly less than "K" does for kilobyte, AND perhaps slightly more than "K" does for "thousand" (as in 100K salary). If we are going to accept an original research argument regarding "the kilo", why would this not be next:? For comparison with above: --JimWae (talk) 10:23, 19 November 2011 (UTC)
 * The kilometre, also known as the K, (American spelling: kilometer; SI symbol: km) is a unit of length in the metric system, equal to one thousand metres...
 * The kilometre, also known as "the K", (American spelling: kilometer; SI symbol: km) is a unit of length in the metric system, equal to one thousand metres...
 * The K (SI symbol: km) is a unit of length in the metric system, equal to one thousand metres...
 * The K (symbol: km) is a unit of length in the metric system, equal to one thousand metres...
 * "K" (symbol: km) is an alternate term for a unit of length in the metric system equal to one thousand metres...
 * "K" (symbol: km) is a term for a unit of length in the metric system equal to one thousand metres...


 * In the questions about the kilogram, the first two are correct. The third fourth and fifth are wrong. The sixth and seventh are correct but have a strong element of NPOV because they mention "kilo" first. UK law explicitly states that either "kilogram" or "kilogramme" may be used.  I would be happy to see the word "kilo" disappear from the lede, but if it must appear, then it should be preceded by the phrase "also known infornally as". Martinvl (talk) 10:31, 19 November 2011 (UTC)
 * 4th & 5th are wrong because terms do not have mass--JimWae (talk) 11:09, 19 November 2011 (UTC)
 * 6th & 7th are true and accurate, and would not comment on "formality" if they said "alternate term". One could say they have WP:UNDUE issues if they appeared thus in the lede, but outside the lede (or, say, in a dictionary entry) they would be true and accurate--JimWae (talk) 11:16, 19 November 2011 (UTC)

Two more --JimWae (talk) 10:43, 19 November 2011 (UTC)
 * The kilo (symbol: kg) is known as the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.
 * The "kilo" (symbol: kg) is known as the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.

Since "also known as the kilo" is a remark about the word "kilo", and is not about the kilogram concept, kg (the symbol for the mathematical entity kilogram) cannot be the symbol for the word "kilo". If that seems to be an original research argument, then so is the other argument. --JimWae (talk) 10:47, 19 November 2011 (UTC)

Since there is nothing wrong with the following in meaning or style, AND it is accepted by other editors, I see no reason to move kilo in front of kg. I do wonder if it should not say "also known colloquially as "the kilo"", or "also known colloquially as a "kilo", or "also known less formally as a "kilo" --JimWae (talk) 10:59, 19 November 2011 (UTC)
 * The kilogram or kilogramme (SI symbol: kg), also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram (IPK), which is almost exactly equal to the mass of one liter of water.

Question: If I were a coal merchant, and I took orders over the telephone, and a customer asked for 25 kilos of coal, would I be wrong to write that as "25 kg"? -- de Facto (talk). 14:00, 19 November 2011 (UTC)


 * Another Question:If I were a coal merchant, and I took orders over the telephone, and a customer asked "Kan jy vir my vyf en twintig kilogram steenkool stuur asseblief?", would I be wrong to write that as "25 kg coal?".
 * The answer to both questions in "No", because you would mentally be translating it to formal English before committing it to paper". Martinvl (talk) 14:28, 19 November 2011 (UTC)


 * The answer to both questions is "no" because "kg" is shorthand for the concept conveyed by either the English word "kilo" or the Afrikaans word "kilogram". If I were a coal merchant I may not even realise that there is a longer word for "kilo", but still write it as "kg" - so without any other mental translation. There is no escaping the clear and incontrovertible fact that "kg" is no less the symbol for "kilo", when used in the context of a mass, than it is for "kilogramme" (that's not in the SI brochure English text either) or kilu, cilogram, chilogrammo, quilograma, or a multitude of other words for the same thing. -- de Facto (talk). 15:23, 19 November 2011 (UTC)

The lede is fine now. Whether Kg is the symbol for kilo is an angels on a pinhead debate. Describing "kilo" as "colloquial" is not supported by the appropriate experts.VsevolodKrolikov (talk) 15:43, 19 November 2011 (UTC)


 * "The kilogram" is the SI base unit of mass. "A kilo" is a unit of mass that is equal to the SI base unit of mass. SI does not define "the kilo". --JimWae (talk) 19:22, 19 November 2011 (UTC)


 * What about "kilogramme"? Or "kilu"? -- de Facto (talk). 19:56, 19 November 2011 (UTC)


 * Reword: The kilogram is the SI base unit of mass. "A kilo" is a term for a unit of mass that is equal to the SI base unit of mass. SI does not define the "kilo". The definite article "the" is inappropriate with "kilo" since it can also refer to a kilometre.---JimWae (talk) 20:33, 19 November 2011 (UTC)

I think that this discussion is best left where it is and that people transfer to Wikipedia talk:WikiProject Measurement where this same discussion is taking place, but at a generic level (I revoked half a dozen changes that Defacto made this afternoon and then initiated that discussion). Martinvl (talk) 21:28, 19 November 2011 (UTC) @JimWae: I undid your lede change. Italics are usually used to indicate that a word is a title of a publication or foreign. Btw "Kilo" for kilometre is so rarely attested that many dictionaries don't even bother mentioning it. I really think that whole aspect of the word is a red herring here. VsevolodKrolikov (talk) 23:04, 19 November 2011 (UTC)
 * I agree with the last point. Maybe the usage was once barely common enough to make it into a dictionary, but that doesn't imply that it belongs in a 21st century encyclopedia. Hans Adler 00:44, 20 November 2011 (UTC)

Stability of the international prototype kilogram
In this section, the image appears to show very few measured changes over many years, with straight lines connecting them. Were there really so few measured changes? That seems unlikely, as the kilogram is compared with other (local) standards frequently. If this graph is wildly imprecise, it does not belong in WP. I would expect to see more random-looking fluctuations in the mass over time. David Spector (talk) 19:06, 25 January 2012 (UTC)


 * On the contrary - the third periodic comparison (in 100 years) took place in 1988-1992. Martinvl (talk) 07:40, 26 January 2012 (UTC)

Photo of an actual standard kilogram weight
Why should we prefer a computer generated image (File:CGKilogram.jpg) over the photo of an actual standard kilogram weight (eg. File:Standard kilogram, 2.jpg)? In my opinion a real photo of a standard kilogram weight better represents the topic of this article: a unit of mass and its history. -- Basilicofresco  (msg) 17:00, 13 January 2013 (UTC)
 * All known photographs of the IPK are copyrighted under licenses that are incompatible with the Wikipedia copyright licenses. Therefore, we can link to them but we cannot copy them. -Arch dude (talk) 21:09, 13 January 2013 (UTC)
 * The main problem with the picture of the US standard Kg that you referenced (File:Standard kilogram, 2.jpg) is that there is no visual scale. True, our CGI is not great ( the inch rule is fairly subtle and is too US-centric) but is does at least provide something. Most people that I talk to about this (yes, I'm a geek) are shocked to hear that the IPK is roughly the size of a golf ball. The nested bell jars give no visual queue of the size. What we really need is a CGI that includes a golf ball and a centimeter ruler. I think we should also put the US Kg picture in the article, but down in the proper section.-Arch dude (talk) 01:40, 14 January 2013 (UTC)
 * I added it to the "Stability of the international prototype kilogram" section, which is the first that mentions the "national prototypes." I will attempt to fine the "1915 Natrional Geographic" article from which it was taken, so we can see if this is K4 or K20. -Arch dude (talk) 02:02, 14 January 2013 (UTC)
 * It's K4; it says in the article caption. -- Chetvorno TALK 05:16, 14 January 2013 (UTC)
 * Yes, I put it there after I found the National Geographic article online and added a link to to it on the commons page for the picture. -Arch dude (talk) 16:55, 14 January 2013 (UTC)
 * I agree with Basilicofresco .  The unique thing about the kilogram is it's the only standard defined by an artifact.  Let's have a picture of one of the actual prototypes at top, not a synthetic photoshopped creation. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 05:23, 14 January 2013 (UTC)
 * Referring to Arch dude's scale objection above, I don't think the inch ruler in the CGI image does anything to add s sense of scale to that image.  I didn't notice it until it was pointed out, and it is at such a sharp angle that you can't readily compare it to the prototype.  If that is the objection, it would be easy to add an inset image of a ruler, or a scaling object like a golf ball, to one of the pictures of an actual kilogram prototype in its bell jar.  -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 22:55, 14 January 2013 (UTC)
 * That sounds good. Rather than photoshopping in a ruler or a golf ball, just put in a dimension arrow indicating 39 mm. -Arch dude (talk) 23:32, 14 January 2013 (UTC)
 * Hi all, Chetvorno  asked me for information about my photo Prototype kilogram replica.JPG. I figured I will save him a few copy and paste by answering here directly. That picture was taken at the Cité des Sciences et de l’Industrie, Paris, about 4 years ago. To the best of my knownledge, I can't confirm nor deny that that kilogram prototype is an actual official kilogram prototype, but what I'm sure about is that it was intended to be visually identical to the original prototype of the BIPM. If you want to know more about it, I'm sure you can contact the Cite' by email, or ask some fellow Wikipedian from Paris to go check in person. I'm a tad busy these days, but I'll try to look into it, too. Cheers.  — Preceding unsigned comment added by Japs 88 (talk • contribs) 17:04, 15 January 2013 (UTC)
 * Thank you for your help, Japs 88. I'll see what I can find out.  -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 02:56, 17 January 2013 (UTC)



Is this picture any use for the lead? I took it at home. It is designed to show that the kilogram is used in the domestic situation as well as the laboratory. It is also designed to show the physical size of a cast iron kilogram weight. I can retake the picture (or touch it up) if neccessary (in my view it needs a little more colour). I could also move the credit card under the weight, leaving sufficient so that people can see that it is a credit card, but also that it is not the main feature of the picture. Martinvl (talk) 14:52, 30 January 2013 (UTC)
 * I think that something like this is a very worthwhile addition and should possible be the picture in the infobox. However, it still does not give an idea of the size of the PtIr IPK itself, which I find quite interesting (even if nobody else does.) Perhaps we can put some sort of picture down in the IPK portion of the article? -Arch dude (talk) 16:26, 30 January 2013 (UTC)
 * I have added a note to the IPK caption comparing it to a golf ball. (Similar volume, 20x the mass!)
 * I'd prefer an actual picture of one of the national prototypes (they're identical to the IPK) in the infobox, but your picture would be good in the article. It gives a good sense of the size of an ordinary kilogram weight.  As Arch dude noted, the pt-ir prototypes are denser than lead so they are considerably smaller than ordinary lead or iron kg weights.   -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 17:23, 30 January 2013 (UTC)
 * I have taken another photo (credit card less obtrusive), been bold and changed the lede picture. (BTW, why would we want an INCH ruler in an article about a metric unit?). Martinvl (talk) 21:26, 31 January 2013 (UTC)
 * Surely we don't need a trademark such as the MasterCard logo to be visible. It adds nothing to the reader's understanding.LeadSongDog come howl!  04:51, 17 February 2013 (UTC)

List of national prototypes?
Does anyone know where to find a list of the pt-ir "national prototype" kilogram standards that were distributed to nations, and their numbers? These secondary standards have assumed increased importance due to their role in measuring the mass drift of the IPK, and the article refers to them a lot, so it would be nice to have a list of them in the article. Quinn, 2012, p.144 has a list of the original 40 distributed in 1889, but not the additional ones distributed after. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 09:58, 16 January 2013 (UTC)
 * Are there any? Platinum costs about the same as gold ($1670 per troy ounce today.) A kilogram of platinum therefore costs about $50,000. I suspect that most national labs will make do with secondary standards calibrated against one of the original 40 and made of something like invar. -Arch dude (talk) 15:59, 16 January 2013 (UTC)
 * On the contrary. In the first batch, 40 kilogram weights were made and were calibrated against each other.  The various weights (including the IPK and six working copies at the BIPM) were distributed by lot.  AS far as the BIPM was concerned, all were as close as possible to being identical. Anyway, for most countries, $50,000 is peanuts for a one-off investment of this nature. Martinvl (talk) 16:07, 16 January 2013 (UTC)


 * There were a lot of additional ones made since 1889. As of now, the series extends to 84. including the IPK and its six duplicates at the BIPM Davis, 2004, p.304.  The previous source lists the additional prototypes created since 1993, nos. 78-84, so all we need is an account of numbers 41-77. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 19:36, 16 January 2013 (UTC)
 * I think that a separate article, List of IPK secondary standards (or some such) is a good idea. With a total of 84 items, the list is clearly well bounded. Note: there are 193 member states in the United Nations, and the 84 known secondary standards are distributed amongst considerably fewer than 84 national labs. Therefore, most national labs do not have such a standard. This is consistent with other standards such as UTC: many labs, including national labs, derive their standards from a small number of better-funded national labs. -Arch dude (talk) 23:56, 20 January 2013 (UTC)
 * If we're going to create a secondary article, my preference would be to split off the discussion of alternate definitions of the kilogram into a new article, Proposed alternate mass standards or something (leaving an introductory summary in this article). That discussion takes up the majority of this article, but is not directly relevant to the current kilogram.  In contrast, this article is missing a few subjects which are more germane to the kilogram standard.  It needs a section on traceability - the structure of secondary standards which ultimately enforces the accuracy of our bathroom scales and net weights of products at our supermarket.  The list of pt-ir national prototypes would be an important part of this.  There also needs to be mention of how the kilogram defines the remaining customary units such as the pound and the grain, so the IPK is the definition of virtually every mass unit used on earth. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 03:04, 21 January 2013 (UTC)
 * In response to Arch dude, how many of the UN's 193 member states have a national laboratory? Does Liechtenstein (population 35,000) have a national laboratory, or do they pay a contribution to Switzerland's national laboratory?  Likewise with Andorra, San Marino, Monacco.  The reality is that only countries that have signed the Metre Convention have their own prototype kilograms: 54 countries have full memebeship and another 37 have associate membership. BTW, our bathroom scales are probalby not regulated which is why you might see the text "Not for use in trade" written on them.
 * In response to Chetvorno's comments about tracability, maybe he might like to read New SI definitions. It is hoped that by the end of next year, the IPK will be a secondary standard. Martinvl (talk) 07:34, 21 January 2013 (UTC)
 * That's interesting. Again, a lot of this traceability stuff is relevant and should be in the article, at least in summary. -- Chetvorno <i style="color:purple; font-size:smaller;">TALK</i> 04:39, 22 January 2013 (UTC)
 * I have added a sentence to the lede and extended a sentence in the body to explicitly include the word "traceabilty".

Image - mass vs force
I have replaced the image of the little girl on a swing with a pair of images, one of which shows a device that measures mass and the other force. I felt that the picture of the little girl did not convey any informatiom unless one read the somewhat contorted description. Martinvl (talk) 13:27, 7 February 2013 (UTC)

Bell jar or ruler
Earlier today I rearranged some of the images in this article. User:Bill le Conquérant undid one of the changes by replacing the "US prototype within a bell-jar" with the "Computer generated image next to as ruler" on the pretext that the computer-generated image gave a much better idea of the size of the IPK. (Both pictures shopwn alongside). In my view, the size of the IPK is far less important than fact that it is kept in a vaccuum inside a bell-jar. I did make a note that the IPK is about the size of a golf-ball, but significantly heavier. Bill le Conquérant deleted that description as well, I would like to undo his changes. What do others think? Martinvl (talk) 19:37, 7 February 2013 (UTC)


 * While I'd like to see some indication of scale in the bell jar photo, I think that's adequately compensated for by the description. The computer-generated image is really nicely done and the ruler is useful, but my preference would be for the actual photo.  <span style="padding:3px;color:gray;font:400 0.9em 'Garamond', serif">Garamond <span style="padding:3px;color:gray;font:400 0.9em 'Garamond', serif">Lethe  20:01, 7 February 2013 (UTC)


 * I think you forgot to mention that I had added the cgi image to the section about the IPK that had no image before. You then replaced the image that I had added. You could have added the new image in addition to my earlier one.


 * Why not have both? Bill le Conquérant (talk) 20:07, 7 February 2013 (UTC)

In my opinion, a photo of a replica is no more or less "real" than a CGI image. In both cases, the image is a model of the real artifact rather than a photo of the real artifact. That's why I originally added an image of a "real" 1915 photograph of the real K4 prototype. I felt that this was one step closer to "real" than either of the two images here. We don't even know that the NIST replica is actually a PtIr cylinder of mass 1 Kg, (as a U. S. taxpayer I would be upset if it were. Why pay $50,000 for a display piece that is never used as a measurement standard?) The bell jars are no more or less interesting than other elements, if any, of the environment of the standard (either the U. S. standard or the IPK itself.) What does the vault look like? Are there other environmental controls? What about Mercury in the environment? How often is the standard exposed and handled? So, I !vote for the 1915 photograph. As an alternative, I vote feo using all three images. -Arch dude (talk) 01:31, 8 February 2013 (UTC)

Over 214 years ago
I have a question regarding the statement "scientists over 214 years ago managed to make the mass of the Kilogram of the Archives..". It appears that the comment was added in 2009.

I'm interested in how such references are maintained since there isn't a clear indication of the date of the event or the date of the statement. I've found that Wikipedia recommends the use of the template when making a remark which may become outdated. However, I'm not sure if it applies to such a case as this.

Should this reference be updated now? I think it should be 219 years ago. However, maybe it should be left as is because it's not critical to understanding the article.
 * That age is not hard text, it is displayed using 1799 which is rendered correctly as 225. LeadSongDog come howl!  01:38, 18 September 2013 (UTC)
 * I see that now :). Now that this is resolved, do I delete this section of the talk page?12.27.253.143 (talk) 15:18, 18 September 2013 (UTC)


 * No need, after 100 days a bot will automatically move the thread to the archives. —  Reatlas  (talk)  09:32, 19 September 2013 (UTC)

What is correct?
In this article it is written both "4°C" and "4 °C" (with a blank in between). I know it is not of any great importance, but I wonder what is correct, gramatically. Adville (talk) 11:58, 24 September 2013 (UTC)
 * We normally follow wp:MOSNUM, though it differs in some such details from formal SI usage. Grammar doesn't really enter into it.LeadSongDog come howl!  22:06, 24 September 2013 (UTC)
 * Thanks! Adville (talk) 08:34, 25 September 2013 (UTC)
 * In this case it's most correct to insert a non-breaking space between the value and the unit symbol. My bigger question is with the number itself, and consistency with the article on the litre. Apparently the original definition of the gram (1795) was "the mass of 1 cubic centimetre of water at the melting point of ice", i.e. presumably 0 °C. This would make 1 kg equal to the mass of 1 cubic decimetre of water, i.e. 1 litre, at 0 °C. This is from http://www.metrodiff.org/cmsms/index.php?page=18_germinal_an_3 --- 4 °C is the temperature at which water is densest, and it relates to a later redefinition of the litre from 1901 in which it was defined as the volume of 1 kg pure distilled water at its maximal density. Archon 2488 (talk) 00:37, 14 October 2013 (UTC)

Equivalency to Grams
I expected to see an equivalency to grams in the heading text, and didn't. Is a kilogram exactly 1000 grams? If not, there should be a note and link to the deeper discussion. Charles Merriam (talk) 23:47, 1 December 2013 (UTC)
 * Yes, a kilogram is exactly 1000 grams. 2003:51:4712:F301:9072:C319:5738:7C3C (talk) 12:00, 12 September 2014 (UTC)
 * at least, as long as you assume that mass is additive at all. --dab (𒁳) 14:02, 2 February 2015 (UTC)

1790s definition
So we have a reference that the 1795 definition referred to water at melting point. Then we say the 1799 prototype was made using water at "4 °C". But we do not say when they decided to change the reference temperature. Nor do we explain why the revolutionary French should be using the Celsius scale (rather than e.g. Réaumur). Perhaps they did use the Celsius scale? or Perhaps they just said "water at maximum density" and a Wikipedian silently glossed this as "4 °C". This would be ok, but it would be nice to know, so how about some kind of reference for all of this?

Also, the article lead claims that the 1799 prototype "had a mass equal to the mass of 1.000025 liters" -- I suggest any number given to seven significant digits is worthy of a reference. They would  not have been able to get seven digit precision in 1799 (the gravet in 1793 is given as "18.841 grains". I suppose a five-digit precision is reasonable for the period, and just because they give five figures does not mean that they reliably measured to five digits; certainly not to seven) -- so who came up with the "1.000025" and when (the tense used suggests this was a measurement taken in 1799)? --dab (𒁳) 14:45, 2 February 2015 (UTC)

Measurement incorrect
Kilogram is 10cm^3 and not 1cm^3 — Preceding unsigned comment added by 65.34.84.175 (talk) 13:23, 21 June 2014 (UTC)

'''This is nonsense. Do not put this nonsense into the article or you will be blocked. Jc3s5h (talk) 19:50, 21 June 2014 (UTC)

Errr... Jc3s5h, i think the ip editor is correct. A kilogram is approximately the weight of one litre of water, which is 10x10x10cm or 10cm^3. Also, using bold font and threatening off the bat with blocking a user is not a very polite way to engage in a conversation and may be the reason why so far no one clarified this in the lead. PizzaMan (♨♨) 12:26, 15 March 2015 (UTC)


 * The convention of writing measurements is that an exponent only applies to the unit, not the number. I will also use the available Wikipedia editing markup to write the exponent correctly. I will also insert a nonbreaking space to separate the number from the unit, as is conventional. So the markup becomes 10&amp;nbsp;cm3 . It is rendered as 10 cm3. It means 10 (cm3). To express a cube 10 cm on a side, you would write (10 cm)3. Jc3s5h (talk) 12:37, 15 March 2015 (UTC)


 * Actually i think the ip editor was possibly just confused because in the lead of this article about the kilogram, it says "the gram is defined as...". That, in turn, lead me to misread it. I added a "1/1000th of a kilogram" to avoid that. PS Note that the very first sentences of a WP article often contain stuff that no one really cares about as the result some tedious discussion about definitions or other details. So i caught myself skipping to the second paragraph to start reading and i expect i'm not the only one. So at that point especially, it's confusing to talk about grams in stead of kilograms. PizzaMan (♨♨) 12:44, 15 March 2015 (UTC)


 * The pattern I've noticed, which I can't explain, is that after any kind of contentious series of edits (such as the edit warring in June 2014 where another editor using several IP addresses decided to cruise in and change to British spelling) other IP editors decide to pile on and commit various kinds of vandalism. So I have less tolerance for goofy edits right after an edit war than at other times. Jc3s5h (talk) 13:12, 15 March 2015 (UTC)


 * Didn't know this was following an edit war. In such a case indeed it's questionable whether you still have to assume good faith. PizzaMan (♨♨) 18:52, 15 March 2015 (UTC)

Mass of the IPK cannot change
The article currently says "After the International Prototype Kilogram had been found to vary in mass over time,...". But that's clearly incorrect. The mass of the IPK is always exactly 1kg, by definition, and so it cannot vary, even if the IPK changes its physical composition in such a way that the kilogram is no longer the same as it was in the past. We need a better way to phrase this. What is really happening is that the IPK is changing its physical composition and therefore the mass of everything else in the universe, as measured in kilograms, is varying. Mikeplokta (talk) 06:47, 19 July 2015 (UTC)
 * The way you are phrasing this, you are confusing a change of mass with the change of the measurement of mass in terms of a unit. Even if the effect was more pronounced (say 10% per annum), we would refer to it as the IPK's mass changing.  One could refer to the measurement of mass in kilograms of everything else changing, while at the same time saying that the mass of stable objects (such as an object consisting of a defined number of atoms of a specific element) remaining constant.  One would say that the unit of measurement varies with time, not the mass of the object measured in terms of it.  —Quondum 13:31, 19 July 2015 (UTC)
 * No, I could chop 10% off the IPK, and its mass still wouldn't change. It would be exactly 1kg (at least until such a time as my assault was noticed, and the definition of the kilogram was changed). If you think that removing a piece from the IPK would change its mass (as measured in kilograms), please answer the following two questions: What was its mass before a piece was removed, and what was its mass after a piece was removed. I know it's counter-intuitive, and that's why they propose to improve the definition of the kilogram so that it's not dependent on a physical reference sample. Mikeplokta (talk) 14:53, 19 July 2015 (UTC)
 * Quondum is correct. The mass of the IPK certainly can change; and it undoubtedly has—and is, Mikeplokta. Read the citations to Metrologia, where many scientists responsible for maintaining the IPK write about their concern over its clear lack of mass stability. This article's terminology is consistent with the citations; that's all that Wikipedia requires of its wikipedians. If you read the citations and still think you have keen insight beyond that of the scientists, you should take it up with them. Please tell them of the title you chose for this discussion thread (“Mass of the IPK cannot change”); if you can convince them of that, they will be greatly relieved.


 * By your reasoning, if the mass of the IPK changes, the magnitude of the kilogram changes (which is true), and therefore, the IPK's mass doesn’t change (false) because the IPK is still one kilogram by definition (true). But scientists know that the mass of the proton, for instance, has not changed in the last 100 years even though the unit of measure for expressing the proton's mass (the gram and kilogram) has clearly drifted by an unknown amount. This is why the scientists are endeavoring to define the unit measure of mass in terms of an invariant property of nature rather than a hunk of platinum/iridium that may well be absorbing atmospheric mercury or, possibly, hydrogen ions from unfortunately chosen hydrocarbon solvents (platinum is a catalyst that can atomize, ionize, and absorb ions into its structure).


 * You concluded your paragraph with a correct sentence, Mikeplokta: …therefore the mass of everything else in the universe, as measured in kilograms, is varying. If the article makes that statement with that particular clause (“in terms of kilograms”), then you would be right to correct the error. But the article does not; it refers to the instability in the IPK’s “mass”, not how the number of “kilograms” comprising the IPK is changing (it’s always precisely one kilogram by definition).


 * You seem to be getting rather hung up with circuitous logical fallacy, that “kilogram” means “mass.” Alas, it does not. The kilogram is but a unit of measure, or an equivalency. One could theoretically characterize the mass of the IPK in proton equivalents, which is a perfectly stable quantity and equally stable unit of measure for quantifying mass. As the mass of the IPK has drifted, it will be precisely one kilogram until the definition of the kilogram is formally redefined. However, the IPK’s unstable mass, as expressed in terms of the number of proton-equivalents, would change; the IPK currently has a mass of about $5.979$ protons. Quantifying mass in terms of atom counting is the objective of the Avogadro Project. In fact, surprising results from the Avogadro Project resulted in a mild shakeup in how research on the watt balance was done. How do I know this? Because I exchanged scores of emails with a key researcher at the NIST while working on this article.


 * (BTW, in addition to proton-equivalents, I was going to also mention Planck masses—the fundamental natural unit of measure for mass—but I anticipated that would drag in a discussion about how, as the magnitude of the IPK changes, and the magnitude of the kilogram, many of the Planck unit's equivalent units of measure like Atomic mass unit and Electronvolt would also change. *Sigh*). Greg L (talk) 17:07, 19 July 2015 (UTC)


 * In fact, while it wouldn't be a particular good standard, they could have defined the kilogram to be the mass of some duck somewhere in Sèvres France and the IPK to be that very duck. As that duck eats or poops, it's still defined to weigh exactly one kilogram.  So, relative to that IPK, I suppose that you could say that everything else in the Universe is changing, but I think the rest of the Universe would say it's the duck that's changing. 70.109.183.210 (talk) 04:34, 20 July 2015 (UTC)


 * Pretty much. That’s the gist of the issue with the stability of an artifact that underpins much of the SI system of measurement. They thought that protecting it under three nested bell jars at atmospheric pressure would be sufficient to isolate it from mass-changing influences, but they were wrong. Something is making nearly all the copies increase in mass relative to the IPK. Given that the IPK is the best protected of the mass artifacts, it is likely that it too is increasing in mass; just not as much as most of its copies. Greg L (talk) 05:20, 20 July 2015 (UTC)

Engvar
It seems strange and out of place that this article is supposedly written in American English. Considering that the subject matter is more applicable in British English contexts (US is the primary geographic where the kilogram is not an everyday unit of measure), I propose to switch this article to British English, just as is already the case with most other articles relating to SI. —Quondum 04:43, 8 July 2015 (UTC)
 * Yes this article has deviated from the other SI unit articles for too long. An early major contributor wanted it that way. LeadSongDog come howl!  05:00, 8 July 2015 (UTC)
 * I've removed the edit note claiming American English as being without basis in MOS:TIES, and I feel that in this case WP:RETAIN is not sufficient to motivate retention of the claimed variant. In particular, the articles relating to SI act as a set and consistency across these articles is IMO appropriate.  While there are not strong national ties to British English, there are strong usage ties, which seems to me to be the way that MOS:TIES should have been worded in the first place.  I will allow some time for comment before implementing this proposal.  —Quondum 13:37, 10 July 2015 (UTC)

This article has no British ties either, so I disagree that the English variant should be British, and disagree with the premature change. The article has always had US English spellings, so it should be changed back. Irn Bimba (talk) 21:16, 18 July 2015 (UTC)

• User:Bimba is precisely correct. WP:RETAIN and the related rules under WP:ENGVAR are perfectly clear. There is zero consensus here to do as you unilaterally took upon yourself to do (change the style of English) with this edit, Quondum. The only strong national tie the SI system has is to French; that issue is clearly moot here on en.Wikipedia. Please take the time to read and understand Wikipedia’s manual of style and engage others on the talk pages there to understand what the rules are and why they exist. To flout the bedrock rule of WP:ENGVAR requires, per WP:CONLIMITED, an overwhelming and wide consensus, which does not exist here—not by any stretch. WP:RETAIN is a bedrock principle intended to avoid untold wikidrama and flamewars that occurred all over en.Wikipedia for a number of years. Greg L (talk) 04:22, 19 July 2015 (UTC)


 * I missed the demurring comment when I made the change; had I realized that there was dissent I would not have made the change. It is certainly not my intent to act in a controvertial fashion.  —Quondum 05:02, 19 July 2015 (UTC)


 * Thank you, Quondum. Best wishes and happy editing. Greg L (talk) 05:10, 19 July 2015 (UTC)

Since it seems that this article is to be written in American English, should instances of British English such as "centimetre" be changed to the American spelling of "centimeter"? NT396 (talk) 07:38, 13 September 2015 (UTC)

Doesn't the watt balance still use an artifact?
The goal is redefine the kilogram without using any artifacts like that mass under the bell jars. However, the watt balance doesn't eliminate this! It measures the force of gravity of an object as a specific point within earth's gravitational field. In essence, the entire earth itself is the artifact and you have to return to the exact same location everytime if you want to accurately measure the kilogram. (because the earth's gravitational field varies over the surface of the earth. — Preceding unsigned comment added by 50.157.226.255 (talk) 18:17, 29 April 2015 (UTC)
 * When using the Watt balance, the Kilogram is defined with respect to the local gravitational field, but the local gravitational field is in turn measured using a gravitometer that does not depend on the mass of the kilogram. Thus, the definition can be generalized to any accelerated frame of reference, not just a particular point near the Earth's surface. Therefore, no artifact is used as part of the definition. As a practical matter, we use a large mass (e.g. the Earth) as part of the practical implementation of the definition, because a location within the gravity field of a large mass is the most stable accelerated frame of reference we currently have access to. -Arch dude (talk) 04:18, 19 July 2015 (UTC)
 * To second this, no, it does not. First of all, gravity at a particular point on Earth is not constant; tides cause significant periodic fluctuations.  Watt balance measurements do require that gravity be known to the requisite accuracy for the duration of a single measurement, which is why extremely accurate absolute gravimeters are an essential part of the experimental setup.  But these don't assume the acceleration of gravity, they measure the acceleration of a freely falling object in vacuum.  (Which requires only the metre and the second.)  This measured acceleration is removed from the final result, so its value does not affect the result.  — Preceding unsigned comment added by 71.41.210.146 (talk) 18:52, 13 September 2015 (UTC)

The IPK was also used in the extraordinary calibrations of 2014.
Lots of stuff in the April 2015 Metrologia. In order to determine the most accurate possible value for h, a special calibration campaign was conducted over 2014 to minimize uncertainty between the IPK and the kilograms used by various watt balance and Avogdaro experiments. This did not use a large number of national prototypes, but is checking the BIPM working prototypes and the prototypes used by the measurement experiments.

discovered two interesting things about the various kilogram copies since the third IPK:

I don't have the gumption to write the necessary text ATM, so I'm leaving this here in case it inspires someone. 71.41.210.146 (talk) 19:13, 13 September 2015 (UTC)
 * 1) Little-used prototypes, such as the official copies, did not show a continuation of the drift observed during the third periodic verification.
 * 2) The BIPM working kilogram was found to be $35 ug$ lighter than the IPK, because the working prototypes had lost mass due to wear since the third periodic verification.

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 * The Wayback link is correct, but I found the renamed page in the original source and used that link instead. 71.41.210.146 (talk) 16:41, 14 September 2015 (UTC)

Split proposal
International prototype kilogram can be a separated article. -- ChongDae (talk) 01:41, 17 November 2015 (UTC)

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Meter/Metre inconsistency in article.
The article is inconsistent in its spelling of the word for "the basic unit of length in the metric system" and its derivatives.

I propose metre to follow the standard of the Wikipedia article of "Metre". Same with litre. Even though I use "meter" and "liter", I propose that we use "metre" and "litre" here to follow the standards for those two articles.

At least it will make it a bit more consistent and easier to follow. What do you think? 8.40.151.110 (talk) 01:44, 9 April 2017 (UTC)

Well, I did it. It makes it look a bit neater. 8.40.151.110 (talk) 01:48, 9 April 2017 (UTC)

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Grave forgotten
well, what about "cail", sign c, deriving from chilog[ram]. so one gram would be 1 mc, and a tonne be 1 Kc Tabascofernandez (talk) 00:42, 15 July 2017 (UTC)

Provisional kilogram related to provisional meter
I inserted the second word [provisional] in the sentence "The gram was provisionally defined in 1795 as the mass of one cubic [provisional] centimetre of water at the melting point of ice." (diff) Chetvorno reverted my edit, so let me explain. The current sentence is deceptive because it mentions the provisional temperature while being silent about the provisional metre. This easily results in the misconception that the difference between the provisional (1795) and the final (1799) kilogram was the temperature (0°C vs 4°C). However, if that was true, the provisional kilogram would have been 0.01% lighter than the final one. In reality the provisional kilogram was 0.09% heavier, because the provisional metre was 0.03% larger than the final one. So the temperature effect has the wrong sign, and it is ignorable compared to the effect of the redefinition of the metre. A similar misconception is present in a footnote: "The provisional kilogram standard had been fabricated in accordance with a single, inaccurate measurement of the density of water made earlier by Antoine Lavoisier". In reality, the new measurement by Lefevre-Gineau was not more accurate than Lavoisier's. Lefevre-Gineau measured the same density at 0°C, and added 0.01% to obtain the value at 4°C. Ceinturion (talk) 17:39, 26 October 2017 (UTC)

Stability of the international prototype kilogram
There's this big chunk of relatively indigestible text about cleaning the artefacts:

''Accordingly, they are cleaned in a process the BIPM developed between 1939 and 1946 known as "the BIPM cleaning method"[47] that comprises firmly rubbing with a chamois soaked in equal parts ether and ethanol, followed by steam cleaning with bi-distilled water, and allowing the prototypes to settle for 7–10 days before verification. Before the BIPM's published report in 1994 detailing the relative change in mass of the prototypes, different standard bodies used different techniques to clean their prototypes. The NIST's practice before then was to soak and rinse its two prototypes first in benzene, then in ethanol, and to then clean them with a jet of bi-distilled water steam. Cleaning the prototypes removes between 5 and 60 µg of contamination depending largely on the time elapsed since the last cleaning. Further, a second cleaning can remove up to 10 µg more. After cleaning—even when they are stored under their bell jars—the IPK and its replicas immediately begin gaining mass again. The BIPM even developed a model of this gain and concluded that it averaged 1.11 µg per month for the first 3 months after cleaning and then decreased to an average of about 1 µg per year thereafter. Since check standards like K4 are not cleaned for routine calibrations of other mass standards—a precaution to minimize the potential for wear and handling damage—the BIPM's model of time-dependent mass gain has been used as an "after cleaning" correction factor.''

In vernacular, it says three things:

So they are cleaned regularly with a special process. After cleaning, the artefacts gain mass at a disproportionately rapid rate. The mass of the artefacts is now defined as their mass after cleaning.

It is very easy to understand what matters about cleaning, because the sentences are short, and say what they mean. It doesn't matter how the kilograms are cleaned. We may assume with solvents and purified water, and we'd be right. Sbalfour (talk) 21:03, 21 January 2018 (UTC)

Proposed future definitions
This section seems like sheer speculation, something like we'd find in the popular press like Scientific American. As I recall, the kilogram among other units, was supposed to be redefined in 2015, then it was moved to 2016, then 2018 and we're not there yet. Only one (possibly 2) of these procedures is actually under consideration as a replacement for the definition. This is an encyclopedia - it's supposed to be a well-worn road. I just think this should probably be moved out of the article and into one appropriately titled, like "Speculative realization techniques" or whatever. Sbalfour (talk) 20:22, 21 January 2018 (UTC)


 * The section seem accurate enough (I don't agree with your characterization), but needs to be brought up to date: the CIPM has made its recommendation, and it is only awaiting the CGPM's final ratification, which seems certain. How the kilogram will be defined does belong here.  The extensive discussion of what were historical possibilities, in the subsections, seems overweight for this article, but it is good material that belongs in an article dealing with history of the SI.  —Quondum 10:48, 25 February 2018 (UTC)

Counted Si atoms
Does anyone know about this ball of counted Si-atoms as an etalon for 1kg? Purgy (talk) 10:40, 2 April 2018 (UTC)
 * I presume you mean the French word étalon, not the English word. The Si ball was one of the competing approaches for a redefinition of the kilogram, but this is now essentially only of historical interest: the CIPM decided on the definition in terms of physical constants and it only awaits a final vote by the CGPM to approve it near the end of 2018.  —Quondum 13:30, 3 April 2018 (UTC)
 * Thank you for the info, and yes, I did not know of the restricted meaning in English. Purgy (talk) 18:00, 3 April 2018 (UTC)

Speculative/anecdotal claims about dkg
I am sorry, but I do not feel sufficiently versed to supply information on this, considered as reliably sourced to WP standards. Nevertheless, here is a link to an entry in a classical Greek dictionary (Liddell-Scott) about the spelling and meaning (=ten) of the word deka (no abbreviation). I am rather clueless how to source the most wide spread vernacular of grocery shoppers, who in Austria and southern parts of Germany regularly order goods (up to 2 pounds/1kg) in xy deka (verbally) (i.e. in dag, as opposed to the rest of Germany, where 'gramm is prevailingly used). How would you describe ordering habits in your country for bulk goods per mass in this range: quarter-pounds, ounces, grams, ...? Obviously, the spelling deca- is one of many mystifications of a classical term.

BTW, the dkg (for 10g,) in use before the SI accepted "dag" (~1975), was replaced to avoid confusion with "deci-kilogram", which would amount to the tenfold mass :p. I cannot comment on the Italian habits. Purgy (talk) 13:12, 1 April 2018 (UTC)


 * The was that it was in is in Central Europe, and this claim was  to "much of Europe".  Even the original claim about the origin of the abbreviation seems to have been a presumption by the editor.  I have managed to locate very little on the topic (basically by Googling), but this thread seems to give a feel: only in a few countries (such as Czech Republic, Hungary, Poland, eastern Austria), is it still in use, and not necessarily in shops.  Your edit created that implication that the abbreviation dkg is traced directly to the Greek word, which seems implausible: it would imply that Greek was in common usage in the places that "dkg" came into common use.  I have come across a 1968 US journal article that makes it look like "dk" was a non-SI metric prefix that preceded the SI "da", which supports your final comment.  That the term "decagram" (or "dekagram") was or is in use is not relevant in this section; neither is its origin especially if unsourced.  I felt that it was fair to remove potential speculation on origin of the symbol/abbreviation, even without your change.  I added the citation needed tags because the claims on the use of "dkg" are evidently based on editors' personal experiences, which would make it unsuitable for inclusion.  —Quondum 14:43, 1 April 2018 (UTC)


 * Liddell-Scott etc. is irrelevant here. "dkg" was simply an older standard abbreviation, and corresponds to one of the two German spellings, dekagram.
 * As for how common it is in commerce, you'd think that if it's a common retail unit, it would also be used in cookbooks, dietary recommendations, and so on. Some quick checks using Google nGrams show that it is far less common than kg or g for Fleisch (meat), about 25x less common in fact. Now, Google Books of course doesn't represent spoken language faithfully, so this has to be taken with a grain of salt. If you just do a general Google search for ["dkg Fleisch"], there are only 69 hits, which isn't promising, either. It still leaves us needing some non-WP:OR evidence for its common use. --Macrakis (talk) 18:55, 1 April 2018 (UTC)
 * Liddel-Scott is, imho, a reliable source for both correctly spelling this prefix as "deka-" and not as "deca-"; and for setting up the Greek roots of the prefix.
 * As of 2018 the abbreviation "dkg" is, afaik, in no noteworthy use anywhere in Europe. It is deprecated since the standardization of "dag" for the very same meaning, and so, more or less immediately, all textbooks in schools were changed to the new standard. As a consequence, if this unit is used at all in written form, nowadays only "dag" conforms to legal prescriptions, and is in official use (retail). I therefore plead for removing the unsourced claim of "dkg" being in use in central Europe, in spite of the obvious non-vanishing from cookbooks and other written documentary of the past.
 * In my experience, the overwhelming use of this entity was always outside of formal applications (restricted to spoken language, to handwritten adverts, ...). In printed form the "g" and the "kg" always covered most needs. As a consequence of declining importance of unpacked grocery goods even the rudimentary use (outside of conversion exercises in elementary school) of the unit "dag" is repressed further.
 * Regardless of the respective abbreviation, in German speaking regions this unit was always articulated as "deka" (omitting the gramm), except for a distinct spelling of "dkg" (dee-kaa-gee).
 * I am not aware of any other correct German spelling besides "Dekagramm", with lower-case "d" as a unit symbol.
 * The Italian "etto-" (pl.: "etti-") is the obvious Italian variant (suppressing the initial aspiration, and hardening the t for eliding the "k") of the SI-prefix "hekto-", stemming from the Greek ἑκατόν (hekaton) for "hundred".Purgy (talk) 10:40, 2 April 2018 (UTC)


 * I would support the removal of the bullet point about "dkg". That was why I tagged it: its veracity and notability needs checking.  This article does not need to document non-mainstream, outdated variant uses of symbols.   —Quondum 13:30, 3 April 2018 (UTC)


 * Agreed about removing dkg, at this point we have no WP:OR for it.
 * On the other hand, the use of hectograms in Italy (under the name etto, short for ettogrammo) is well documented and should be mentioned in the article..
 * As for Liddell-Scott, it is a reliable source for ancient Greek, not for modern languages which borrow from Greek. The etymology of deca-/deka- belongs in Deca-, not here. LS is certainly not a source for the "correct" spelling of the prefix, which is determined by the CIPM. Anyway, both 'c' and 'k' are used in different Romanizations of Greek. --Macrakis (talk) 15:03, 3 April 2018 (UTC)


 * The mention of "etti" seems out of place to me. The section is about SI multiples and their prefixes, as applied to the kilogram, and goes on to mention notable common non-SI usage such as the tonne.  "dkg" might have qualified if it occurred in mainstream or official contexts and hence that it required disambiguation.  In contrast, "etto"/"etti" is clearly just a local common name for a standard unit, which one would seek in an Italian dictionary.  Are we going to describe how delicatessens worldwide usually price foodstuffs bought in portion sizes "per 100 g" (or the local equivalent name), and then elaborate on the actual terms used in each language?  This, to me, is not the focus of this article, and nor would it be of interest to the vast majority of readers of the English version of WP (it would belong in an Italian version).  If it is to be included here, IMO it belongs in a "Common usage" section, though I do not support addition of such a section.  —Quondum 17:11, 3 April 2018 (UTC)


 * We already document which sub/multiples are "common" by having them in boldface in the SI Multiples table. The usage of hectograms in Italy as a standard unit is precisely the same case. This is similar to the way that in the hectare article, we document the usage of ares in Russia and decares in Norway and the former Ottoman regions. The content about etti is not about the word, but about the unit: "The hectogram is a very commonly used unit in the retail food trade in Italy"; its name in Italian is relevant not because WP is a multilingual dictionary (which it is not), but because that is the most common form in which it is found. --Macrakis (talk) 19:03, 3 April 2018 (UTC)


 * The hectogram is a very commonly used unit worldwide in food retail, as I pointed out. Italy is not special in its use of the hectogram, only in most places it is called "100 g" (not "hectogram") as in "$4.99 / 100 g"; just like the unit of fuel consumption is "L / 100 km", numbers actually do become de facto parts of units, even though this is not correct SI usage.  If we want to gabble on about common usages (rather than just bolding them), we should not single Italy out.  —Quondum 19:41, 3 April 2018 (UTC)


 * Some SI multiples are commonly used (kilogram, milligram, microgram; kilometer, centimeter, millimeter, micrometer); others are not (megagram, decigram; megameter). We acknowledge that by using boldface in the SI multiples table. Many SI/metric multiples even have their own articles (kilometer, hectare), though I'm not sure some need them (why do we have hectometer?). Here we have a case of a multiple that is very widely used in at least one country. That should be documented in some way.
 * Re "If we want to gabble on", I'd appreciate it if you'd use more respectful language. --Macrakis (talk) 16:22, 4 April 2018 (UTC)

10^(-24) measurement uncertainty
I found a claimed 10-15 μg short-term stability for the Kibble balance in the article. That would be 24 digits accuracy, a ridiculous claim - we have nothing that comes anywhere close to that. I checked the source just to be sure it is not there and removed it, but I was curious: How did such a number make it into the article? It turns out the original article had "10-15 μg" years ago - until someone reduced that by 16 orders of magnitude by adding superscript tags. Always check before you "fix" formatting. --mfb (talk) 17:34, 3 November 2018 (UTC)

Planning our edit strategy for the new definition
Colleagues: We all know that the new definition will (almost certainly) be approved on 18 November and will take effect next May 20. When it does, This article in its present form will no longer make much sense. I think we should plan for an orderly shift to a new article. My own thought is that we need to almost start from scratch. The existing article should be moved to History of the kilogram : such a move will preserve the edit history. That article can then be modified to put it onto the past tense and clean up loose ends. The new article can use whatever material remains relevant from the existing article by following the rules for copying within Wikipedia, specifically by adding attribution in the edit summaries and on the talk page.

I think we should probably modify the lede of this article very soon to note that this change is coming, and we should decide among ourselves on when and how the various actions will take place. Perhaps we can build the new article as a draft? -Arch dude (talk) 03:40, 4 November 2018 (UTC)


 * Parking a reference: May be useful- maybe not. --ClemRutter (talk) 20:57, 9 November 2018 (UTC)


 * I don't think we need to rewrite this article. I've already added text to the lede describing the proposed change. When the vote is final, today supposedly, it will be easy to update that text. The IPK will be the legal standard until May 20, so the material about it is still pertinent for now. The secondary standards will presumably still be used but calibrated in labs like NIST's with Kibble balances instead of being compared to the IPK every 40 years. We already have a detailed description of the new definition and the Kibble balance. I would move that text closer to the top of the article while separating out the material on the proposals that were not adopted and putting them near the end. I would keep all the material in the present article for now, and when the dust settles, perhaps after May 20, consider moving some of the material to a History of the Kilogram or IPK article if this article seems too long.--agr (talk) 13:06, 16 November 2018 (UTC)


 * The sections need to be extensively edited after the vote is finalised, because at the moment a lot of space is taken up by what seem to be multiple proposals whereas presumably only one can be chosen. The proposals that are dismissed should be relegated to a separate section, or possibly even a separate article, on "alternative proposals".
 * —DIV (120.18.220.200 (talk) 11:54, 18 November 2018 (UTC))

First use of the word kilogramme in English - 1797/1795
The article contains the statement that the word kilogramme was used for the first time in English in 1797. Obviously, that is unlikely; why would there have been two years of silence in English after the French introduced it in 1795? Google is better at finding the first use of the word: in 1795 it was used in Monthly Review, volume XVII (link), together with gramme, centigramme, and myriagramme. Ceinturion (talk) 19:14, 3 August 2018 (UTC)
 * Done, replaced 1797 by 1795, and added the reference. Unfortunately I couldn't delete the old reference (ref name=OED/) because in some obscure way other references depended on it. Ceinturion (talk) 23:01, 3 August 2018 (UTC)


 * I'm not sure about this. Your reference is a report on the French law, and the terms are 'defined" not "used". They are italicized and are therefore arguably in French. To be "used", as opposed to "defined", we need an actual English sentence that uses the word. I suspect that this is the reason the OED did not use your example. -Arch dude (talk) 17:43, 4 August 2018 (UTC)
 * Arch dude makes a good point: the date is not supposed to be the first time English-speakers heard about some novel French word, but rather when that word came to be adopted in English.  —DIV (120.18.220.200 (talk) 12:03, 18 November 2018 (UTC))

Note 13
Please clarify quantity/quantities at end of note 13: " Assuming the past trend continues, whereby the mean change in mass of the first batch of replicas relative to the IPK over one hundred years was +23.5 σ30 μg." —DIV (120.18.220.200 (talk) 12:24, 18 November 2018 (UTC))

Water temperature
I’ve removed the detail of the water temperature used for the original definition of the kg from the introduction. Our article makes clear that the original definition was at the freezing point and that 4 degrees C came later, but generations is students have learned 4 degrees and it seems to attract unneeded corrections. The temperature is not needed in the introduction, so I took it out.—agr (talk) 22:45, 17 November 2018 (UTC)


 * Right, the temperature is not needed in the introduction. However, in the article, the explanation of the effect of changing the temperature from 0 to 4 °C is an unacceptable contradiction. It suggests that the final kilogram was 0.07% lighter than the provisional one because of the new temperature. However, the new temperature was a small contribution that made the kilogram 0.01% heavier (remember, at 4 °C water is heaviest). In reality the kilogram became lighter because of a more important contribution: the final meter was 0.03% smaller than the provisional one, so the final litre became 0.09% smaller. Ceinturion (talk) 09:38, 18 November 2018 (UTC)

[new comment]The water temperature is crucial since it's weight per volume is varying with temperature. You wright that "Our article makes clear that the original definition was at the freezing point and that 4 degrees C came later..." but this was not clear at all when reading the article. It was more a contradiction. If the original definition was at freezing point, then just find a good reference for it and the problem will be solved31.209.6.140 (talk) 00:06, 19 November 2018 (UTC)[end of comment]

Where is the kilogram standard stored in Saint-Cloud or Sèvres?
Information in related articles is inconsistent 188.186.92.51 (talk) 15:46, 11 December 2018 (UTC)

Photons have no mass
"a light particle’s energy, and hence mass," they can relate it to momentum but not to mass. Michael McGinnis (talk) 19:44, 28 January 2019 (UTC)

Wrong output with Lynx or with style disabled
When viewing the page with Lynx or with Seamonkey with style disabled, the output looks like this: 1 kg in ... ... is equal to ... Avoirdupois   ~= 7000220500000000000cS2.205 pounds^[Note 1] British Gravitational   ~= 6998685000000000000cS0.0685 slugs What are the "7000220500000000000cS" and "6998685000000000000cS" supposed to mean? BTW, the W3C's Validator shows 143 html errors and 12 CSS errors: http://validator.w3.org/unicorn/check?ucn_uri=http%3A%2F%2Fen.wikipedia.org%2Fwiki%2FKilogram&ucn_task=conformance

Wikipedia has become so CSS-heavy that I need to view it with style disabled or it blocks my computer. I can live with this, but I expect that it at least shows the data correctly on any browser. After all an encyclopedia is about content more than form. Ant diaz (talk) 15:21, 20 February 2019 (UTC)

Moved Kilogramme des Archives to a different article
It's now in the Grave (unit) article. Since this was a copy-paste move, details of the edit history are in the kilogram history. -Arch dude (talk) 19:56, 23 May 2019 (UTC)

Moved International prototype kilogram to its own article
I converted International prototype kilogram from a redirect into an article. I copy-pasted the contents from that section of the Kilogram article. Earlier edit histories are therefore still here in the Kilogram article's edit history. -Arch dude (talk) 04:50, 24 May 2019 (UTC)

What to do about the "alternative approaches" section?
The section on alternative approaches to the new definition of Kilogram is no longer very relevant to this article, but it comprises an inordinate amount of the article's content, which constitutes undue weight. I'm not sure what to do with it. It's more relevant to the 2019 redefinition of the SI base units article, but even there it's just too big. It's fascinating and notable (once notable, always notable) so I think it should be split out into a separate article. Any thoughts? -Arch dude (talk) 16:56, 24 May 2019 (UTC)

Consequences of the Redefinition
This page is in need of a heavy overhaul now. I am not sure whether it would be best to just relegate most of the information currently available on it to a new page, or to put it under a "historical kilogram" section, or to just lead each relevant section with the new information while deleting the rest.
 * I'm trying to clean up. I moved Kilogram des Archives into the grave (unit) article, and I am in the process of moving the IPK into its own article. This involves some modifications to the lede and the "previous definitions" sections. -Arch dude (talk) 19:59, 23 May 2019 (UTC)


 * I think the removal of so much material on the IPK, and all pictures of the IPK, is far too extreme a WP:POV reaction to the change in definition. The fact is the IPK is still the secondary standard by which all kilogram measures on Earth, and all the other weight measures, are defined.  The Kibble balance definition is just used to calculate corrections to the IPK.  This article desperately needs a section on Traceability - how the calibration of the scale in your grocery store traces back to the primary definition. That path passes through the national standard kilograms and the IPK.  --Chetvorno<i style="color: Purple;">TALK</i> 18:31, 24 May 2019 (UTC)

Is that Kg diagram thing really necessary?
I get the impetus for replacing the image of the IPK post-redefinition, But I think replacing it with such a simple diagram is simply putting an image there for the sake of having an image. In my opinion, until the page is given an overhaul having no image there would suffice.
 * I also dislike the diagram, but a clean photo of an ordinary kilogram weight would make more sense. There surprisingly few in commons category Weights. The one we have with the credit card would be better that the diagram, though the credit card is a distraction. Another possibility is File:Poids fonte 1 kg 01.jpg, an antique which suggests the long history of the kilogram. I'll be bold an put it in.--agr (talk) 15:53, 22 May 2019 (UTC)
 * We spent a fair amount of time deciding on a picture originally, and we decided we needed a picture that conveyed the physical size of the kilogram mass somehow. An editor then went to the trouble of taking that picture with the credit card to provide scale. I had suggested using coins, but other editors pointed out that coins are regional, while the credit card size is standardized world-wide. I do not like the current picture, since I cannot tell how big that mass is. If you can come up with a better way to convey the scale, then please do so, but I think we should go back to the one with the credit card until we have an alternative. -Arch dude (talk) 17:07, 24 May 2019 (UTC)
 * Prior discussion is at Talk:Kilogram/Archive_7. -Arch dude (talk) 17:25, 24 May 2019 (UTC)
 * I agree with agr and Arch dude, the picture with the credit card would be better. I also feel the deletion of all pictures of the IPK is far too extreme.  The IPK was the primary standard until 4 days ago, the article discusses it extensively, and readers should be able to see a picture of it.  The article explains  that it is no longer the primary standard, and a picture is not going to confuse anyone.  --Chetvorno<i style="color: Purple;">TALK</i> 18:43, 24 May 2019 (UTC)
 * I moved the entire IPK section ot the new article, and this brute-force move included all of the pictures. We can put one of the pictures back as part of further refining the remaining IPK info in this article. I have no interest in doing this, so please feel free. My problem is that the history, and the IPK in particular, were overwhelming the rest of the article, which is supposed to be about the SI unit known as the Kilogram. If you do decide to improve the remaining IPK info, please make sure we don't get back to overbalanced mess we had before. Also note that I'm just one editor and my opinions carry no more weight than yours do -Arch dude (talk) 19:28, 24 May 2019 (UTC)
 * I think the credit card image is unsuitable for the lead infobox image as the credit card is too distracting. Perhaps we could find another image with a scale cue in it. -- DeFacto (talk). 19:14, 24 May 2019 (UTC)
 * Maybe the caption could explain that the credit card is there as a scale cue. --Chetvorno<i style="color: Purple;">TALK</i> 19:33, 24 May 2019 (UTC)

Should "kilo" appear in the first sentence?
believes that the term "kilo" should appear in the first sentence, and I disagree. Yes, the term is used, but it is not supposed to be used for any legal, scientific, or technical purpose according to the US government and BIPM. As this is largely a technical article, I think we should memtion it, but not in the first sentence. If we are to mention it, we need to somehow also identify it as being deprecated. Thoughts? -Arch dude (talk) 19:21, 24 May 2019 (UTC)
 * the English language is not governed by the US government, or by the BIPM, thankfully. "Kilo" is in widespread common usage to mean 1000 grams. According to the OED, the word has been in used in this way in the English language since at least 1870. The free online |OxfordDictionaries.com gives it as a noun meaning "A kilogram". -- DeFacto (talk). 19:38, 24 May 2019 (UTC)
 * I understand your point: yes, it's used that way, and yes, Wikipedia is supposed to follow the usage, not dictate the usage. However, This article is arguably about (or mostly about) the SI unit, not the random concept of "kilogram", so I was hoping we could clue our readers in on this. How about wording like (informally known as kilo)? this is is a minimal intrusion that still provides the essential information. -Arch dude (talk) 19:51, 24 May 2019 (UTC)


 * "kilo" isn't only used informally though, and it certainly isn't an obsolete unit - it's the commonly used short form for "kilogram". The American Meriam-Webster dictionary defines it as a noun meaning "a unit of mass or weight equaling one thousand grams or approximately 2.2 pounds : KILOGRAM". Wikipedia is a general encyclopaedia, not a physics text book. Sure the article can describe the BIPM position on this, and even the US goverment's, but we should not ignore the common usage aspect of the subject or try to imply that it is somehow wrong or invalid usage. -- DeFacto (talk). 20:18, 24 May 2019 (UTC)
 * The current lead sentence is objectively incorrect. The sentence says: "The kilogram or kilogramme (also known as kilo; symbol: kg) is the base unit of mass in the International System of Units (SI). ".  But the "kilo" is explicitly disallowed by The BIPM, who is the authority that defines the SI terminology, so "kilo" is NOT "the base unit of mass in the International System of Units (SI)". It's a term that is used but not a term in the SI, so the sentence is wrong as it stands. -Arch dude (talk) 20:33, 24 May 2019 (UTC)
 * I disagree. The BIPM may define the SI terminology (which may have strict adherents in academia and elsewhere), but they do not dictate what the English word "kilogram" means, or how it becomes used, shortened, or otherwise abbreviated or modified in general usage. The logical conclusion of your argument would be two articles - one for the "SI kilogram" and one for the normal "kilogram". -- DeFacto (talk). 21:07, 24 May 2019 (UTC)
 * The first sentence is a short explanation of the kilogram as a unit of the SI. Thus, it is not appropriate to include kilo. Common or urban language needs to be qualified with context, otherwise it is simply wrong. Common language use always is in context, and is never a definition for technical means, and Webster is not an encyclopedia. Kbrose (talk) 13:33, 25 May 2019 (UTC)
 * A basic principle of Wikipedia is WP:NPOV. This means that all significant perspectives are represented. In this case, that means both the standards bodies and common usage. "Kilo" is clearly a very common name for a kilogram, and it is also very clearly not sanctioned by standards bodies. Both of these truths need to be represented in the lead. The wording does, of course, need to be clear about the difference. --Macrakis (talk) 14:43, 25 May 2019 (UTC)

I am starting to split the "alternatives" section out of this article.
Please stand by. This will take about an hour. After the new article is at least a little bit stable, I will remove most of that material from the Kilogram article an replace it with a brief summary. -Arch dude (talk) 15:21, 26 June 2019 (UTC)
 * OK, I did it. We still need to improve this article. The "new definition" stuff was scattered and replicated in several sections and it's still not a coherent as it should be. But at least now a reader who just wants to know about "kilogram" won't have to wade though the esoteric debate over the new definition. -Arch dude (talk) 17:34, 26 June 2019 (UTC)

Mass relative to a litre of water
I originally added "almost exactly" a few years ago, because "about" gives the casual reader the impression that there is a meaningful difference in everyday life. A litre is about the same as a US quart. A litre is indistinguishable from a kilo of water except in a very well-equipped laboratory. They are the same for practical purposes. -Arch dude (talk) 16:04, 16 October 2019 (UTC)
 * This should be mentioned as the original definition of the kilogram, and is a practical tip for readers to know, but I don't think as much emphasis should be put on it as a usable definition of the kilogram. I believe it was never used as a practical definition in metrology, it was used to define prototype masses such as the Kilogramme des Archives which then became the primary standard. --Chetvorno<i style="color: Purple;">TALK</i> 18:10, 31 October 2019 (UTC)
 * It is very useful in everyday life. You (or a chemist) can accurately measure a litre of water to within 1% or better by weighing it, but not by measuring its volume. -Arch dude (talk) 02:03, 1 November 2019 (UTC)
 * That is certainly untrue. Volume accuracy of volumetric flasks can be a fraction of 1% or even below 0.1%. Kbrose (talk) 02:18, 1 November 2019 (UTC)

So, what IS the current definition for "kilogram"?
Maybe I'm missing it, but I don't see it anywhere in the article. We're told that the new definition is in terms of Plank's constant, and that it's in terms of meters and seconds. But nowhere do I see a statement "A kilogram is now equal to 542.983 gazillion Plank's constants", or equivalent.

The full definition should be in the first or second sentence of the article, then explained in more detail in the body of the article. — Preceding unsigned comment added by 70.89.176.249 (talk) 19:58, 18 June 2019 (UTC)
 * I think you are correct, so I just added the definition. However, It really does need more context even in the lede. I think we need to do some additional restructuring first, though. We have not yet recovered from the fact that this article spent several years as the battleground between proposed redefinitions. Once we clean that mess up, we can focus on the underlying truth that the four definitions (Grave, Kilogram des Archives, IPK, and Core2018) are successive refinements of "the mass of a litre of water". -Arch dude (talk) 16:21, 23 June 2019 (UTC)


 * The current lede still does not include the definition. Admittedly, the new one is a bit of a mouthful, but I'm sure there's people around there smart enough to explain it clearly. — Yerpo Eh? 07:25, 31 October 2019 (UTC)


 * The "official definition of the kilogram" is
 * $$1 \text{kg} = {h \over 6.62607015 \times 10^{-34}} \text{m}^{-2}\text{s} = 1.4755214  \times 10^{40} {h \Delta v_\text{Cs} \over c^2} $$
 * where $$\Delta v_\text{Cs}$$ is the frequency difference between the hyperfine ground state energy levels of cesium, $$h$$ is Planck's constant, and $$c$$ is the speed of light.
 * I doubt this belongs in the lead at all, certainly not in the "first or second sentence". The lead is supposed to be comprehensible to general readers.  "Defining the kilogram" should mean explaining in an understandable way the process by which a value is determined from fundamental constants for prototype kilogram masses like the IPK, not an equation that very few readers will understand. --Chetvorno<i style="color: Purple;">TALK</i> 17:57, 31 October 2019 (UTC)
 * The kilogram is not defined in terms of the IPK, so there is no way to explain how that is done. That's how if used to be done. secondary mass standards are now weighed using a kibble balance. AFAIK the IPK is no longer used at all, much less as a secondary standard. -Arch dude (talk) 02:09, 1 November 2019 (UTC)
 * I wasn't saying that the equation should be included, but I do think that the lede should explain what it means (in brief). — Yerpo Eh? 19:01, 2 November 2019 (UTC)
 * That equation is not the "official definition". It is your (completey correct) expansion of the official definition by mathematical substitution. As stated in the first section of the article after the lede, the formal definition is:
 * The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant $h$ to be $6.626$ when expressed in the unit J⋅s, which is equal to kg⋅m2⋅s−1, where the metre and the second are defined in terms of $c$ and $Δν_{Cs}$.
 * If you think you can make this more comprehensible in the lede, then please feel free to do so. -Arch dude (talk) 05:00, 3 November 2019 (UTC)

The new definition needs more explanation
I'm sure a physicist can understand how a unit of mass can be derived from units of time and distance, but no one else will. This is an encyclopaedia, not a physics textbook, so the article should explain how this works. Richard75 (talk) 20:35, 10 November 2019 (UTC)
 * I tried to address this briefly in the lede. Does this work for you? I think we still need to put a more detailed description of this process, which is called a "realization" of the definition, in a new section of the article. -Arch dude (talk) 23:17, 10 March 2020 (UTC)

Does the section "Acceptance of the Giorgi system, leading to the MKSA system and the SI" contains an error?
The second paragraph of this section starts with the sentence "To summarize, the ultimate reason why the kilogram was chosen over the gram as the base unit of length..." Shouldn't the last word in this quote be "mass", not "length"?

A following sentence in the same paragraph also refer to gram as a unit of time: " 2. the base units of length and time are decimal multiples or submultiples of the meter and the gram..."UriGeva (talk) 08:08, 9 October 2020 (UTC)


 * I edited your first suggestion into the article. I am not sure about your second remark, I agree there is a typo, but I am not sure what the author meant with that statement., could you improve or clarify that statement? Ceinturion (talk) 21:24, 10 October 2020 (UTC)


 * The sentence "2. the base units of length and time are decimal multiples or submultiples of the meter and the gram," talks about base units of length and time and then says they are multiples or submultiples of meter and gram. Meter is a unit of length but gram is not a unit of time. 2601:602:980:5B10:8C02:FA64:7A4F:B1C2 (talk) 22:15, 12 October 2020 (UTC)
 * I made the correction in #2 and #3 in the second paragraph -- replaced "time" with "mass".UriGeva (talk) 07:04, 17 October 2020 (UTC)
 * Thank you all for making these corrections. I have no idea how it happened that I used 'length' (in the first typo) and 'time' (in the second typo), and never noticed that I did that. --Reuqr (talk) 20:16, 24 October 2020 (UTC)