Talk:Kilogram/Archive 6

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Archive 1 Archive 4 Archive 5 Archive 6 Archive 7

Volt is unaffected by the kilogram?

From an editor comment in the article: "The VOLT is indeed defined relative to the newton (which is derived from the kilogram) but the volt’s magnitude is unaffected by variations in the magnitude of the kilogram because the newton appears once in both its numerator and denominator (watt/amp). In turn, the TESLA too is not affected."

Is this true? It's not clear to me that the effect on the magnitude of the ampere with variations in the kilogram is linear. --Random832 (contribs) 16:51, 2 April 2008 (UTC)

Worked the math, it's _not_ linear, it's a square root. If the kilogram were to become 99% of its current value, the ampere would become 99.4987437 of it's current value. --Random832 (contribs) 16:54, 2 April 2008 (UTC)

  • I haven’t seen your math Random832 so I can’t point out the flaw but I believe you are mistaken. If you follow the chain of dependency of the SI definitions and look at how a change in the kilogram affects things, I believe you will find that no matter what, the volt can be reduced to meters per second. This makes sense, since electricty can be viewed in terms of simple mechanical kinetics with electrons (magnetism is the magic paddle that links the mechanical world to that of the electron). The electron-volt (the very small unit of energy) is equal to 1.602176487×10−19 J and the mass of the electron is 9.10938215×10−31 kg. So the velocity of a single electron when it is accelerated to a kinetic energy of one electron-volt is 593,096 meter/second. That much is simple physics. It follows then that the velocity that an entire coulomb of electrons achieve when they pas through an electrostatic potential difference of one volt, in vacuo is 593,096 meter/second, during which time they gain precisely one joule of energy. I believe you’ll find that no matter how one changes the kilogram, the volt always reduces to 593,096 meter/second. Try it. But remember, as the kilogram changes, so too must the numeric value for the mass of the electron, which is a constant in absolute Planck terms (as are the meter and the second in this hypothetical). In the end, after all the terms are crossed out, the volt always comes out in the mathematical wash as 593,096 meter/second; which is to say: if the kilogram were to change, the absolute electrostatic potential of one volt would be unchanged at 9.5882×10−28 Planck units of potential. Greg L (my talk) 23:05, 9 April 2008 (UTC)

    P.S. Good catch about the circular definition of “equals IPK + 42 µg.” Indeed, the correction would have to be expressed in terms of one of the parts-per notations such as percentage or ppb. Thanks. Greg L (my talk) 23:38, 9 April 2008 (UTC)

  • (in specific response to your electron-volt example) But since the ampere would change, the numeric value for the charge of an electron would also change - and I believe the math below establishes that the change would not be in linear proportion to the other change. --Random832 (contribs) 15:26, 10 April 2008 (UTC)
so, if
Is there a problem with this calculation? The 0.990 and 0.995's are each the "new" value of the unit they are attached to - obviously the kilogram won't ever lose a full percent of its mass, but it's easier to calculate. --Random832 (contribs) 15:07, 10 April 2008 (UTC)
  • Hmmmm. Must study this… Greg L (my talk) 18:15, 10 April 2008 (UTC)
  • Been busy in real life. Just enough time to argue on Talk:MOSNUM but not enough for this. I’ll have time this weekend. Greg L (my talk) 20:10, 11 April 2008 (UTC)


Sorry, I really couldn’t follow what you were doing with your mathematics above. Instead of trying to crunch actual values using a 1% change as you did, I elected to counter with yet another analysis. This time, I took care to ensure I used only BIPM definitions from the start, rigorously adhered to them, and used almost no numeric values in the analysis (just nearly pure, symbolic algebra).

This BIPM web site “defines” the watt, volt, and newton. This BIPM web site “defines” the ampere. This one defines the second. And this one defines the meter.

The ampere is defined as such:

The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2×10−7 newton per meter of length.

The ampere can thus be thought of as the product of two factors: [fixed experimental setup per meter of length] · 2×10−7 N. For simplicity, let’s algebraically simplify and express the ampere as follows:

A = K · 2×10−7 N

K = [fixed experimental setup per meter of length]
N = newton of force

The most important thing to note in this simplification is that the fixed experimental setup term, K, contains only two conductors of fixed length at a fixed separation, there is no buried “kilogram” term within; that’s the important part.

Note too that it makes perfect sense to think of the ampere as simply a force. Regardless of the experimental setup (the arbitrary length of the conductors or the separation between them), flowing currents creates a force between conductors. We were all amazed when we got our first big fuel cells running in R&D because fuel cells are amp-rich and voltage-shy. We could entertain ourselves for quite a long time by simply watching 4-gauge cables flex back and forth as we turned the load on and off. In the case of the SI, the BIPM reversed the ampere=force relationship and elected to define the magnitude of the ampere in terms of the force it generates.

Let’s go through the chain of definitions as defined by the BIPM in the SI:

  • V = WA
  • W = JS = J·s–1
  • J = N·m
  • N = m·kg·s–2
  • The second and the meter are the other SI base units (the ampere being the first) but I won’t bother with them since we all know what they are and they are immaterial to this discussion.

Thus, we can define the volt in all the following equivalencies:

V = WA = J·s–1A = (N·m)·s–1A = (m·kg·s–2)·m·s–1A = (m·kg·s–2)·m·s–1K · 2×10−7 N = (m·kg·s–2)·m·s–1K · 2×10−7 (m·kg·s–2)

Now, note this fact about the last equivalency above: it features the kilogram only once in the numerator and denominator. This is the case because it is a term within the newton, which also appears precisely once in the numerator and denominator. That means the volt is invariant with respect to the kilogram. Now let’s look at something else that sheds light about how we think of what electric potential (the volt) is:

(m·kg·s–2)·m·s–1K · 2×10−7 (m·kg·s–2)

…the volt is a velocity: m·s–1 = ms

…except in this case, I believe the actual velocity (here, it crunched to 12×10−7 m/s = 5,000,000 m/s), is really a dimensionless quantity because the experimental setup, K, that defines the ampere is an arbitrary one: even though it’s “one meter of length for conductors one meter apart,” the force between the conductors would change non-linearly as the meter varied. I’m not sure, but I suspect that if you use all-Planck units, the “velocity” of a volt is probably equal to 1 (in the Planck unit of velocity, which is the speed of light). If you solve this velocity kinetically using the mass of the electron (9.10938215×10−31 kg), you end up with 593,096 meter/second. To recap how one arrives at a velocity using mechanical kinetics, here is what I did:

The electron-volt (the very small unit of energy) is equal to 1.602176487×10−19 J and the mass of the electron is 9.10938215×10−31 kg. So the velocity of a single electron when it is accelerated to a kinetic energy of one electron-volt is 593,096 meter/second. It follows then that the velocity that an entire coulomb of electrons achieve when they pas through an electrostatic potential difference of one volt, in vacuo is 593,096 meter/second, during which time they gain precisely one joule of energy. It’s just billiards.

Anyway, the bottom line answer is that the volt, and therefore the tesla, are unaffected by variations in the magnitude of the kilogram. Further, the value of the volt can be expressed as 593,096 m/s for electrons. Further still, this value will not change unless the meter changes independently of the second; a change in the second can not affect the volt because the meter, which is keyed to the velocity of light, changes proportionally with the second.

That’s my analysis. I’m glad you challenged me to this exercise because I didn’t put nearly this much diligence into my previous analysis. In both cases though, I started with the actual BIPM definitions (I didn’t go get “kibibytes” from Wikipedia, nor other secondary opinion or sources) and stuck with straightforward algebra the entire way. Thus, this isn’t original research; it’s math, which is fair game as anyone can analyze the same facts and crunch them (and goof at it too). To me, the algebraic result passes my “grin” tests when I think about electricity in terms of what is going on with the ampere (a quantum phenomenon enlarged to gigantic, observable proportions due to the vast quantity of electrons moving at the same time), and with the volt. Further, it matches perfectly with my view of electricity from a mechanical (kinetics) viewpoint. Let me know if you find a flaw in any of this.

My old boss at the fuel cell lab used to be the head engineer at an electrical utility. He once read a book on quantum mechanics in a lawn chair on the beach in Hawaii for recreation. He and I got all sideways on the above as he simply could not get his mind off the engineering equivalencies and think about the units strictly in terms of the definitions within the SI. This was not easy (for me anyway). I’ve spent hours here on this post, digging into the facts, analyzing consequences, committing the logic to written form, and checking what I wrote to satisfy myself that it seems correct. I’m glad I did though, because I wasn’t entirely sure about leaving the volt and tesla off the list of units that are affected by the kilogram. I trust you’ll let me know if I did a brain fart here.

Greg L (my talk) 20:13, 12 April 2008 (UTC)

What I was trying to get across with my first response above to your electron-volt example is the fact that the number of electrons in a coulomb - and therefore, the mass of a coulomb of electrons, and therefore the amount of energy that they would gain from being accelerated to a particular velocity - would also change. --Random832 (contribs) 22:22, 12 April 2008 (UTC)

Yes, I know that. I said as much in my very first post when I wrote as follows:

I also repeated this in my latest post. I added the underlining in this copy of my text to highlight the relevant point: as you go from one electron to a coulomb, the energy requirement to accelerate to that particular velocity increases proportionally; from one electron-volt to an entire Joule. Right?

If you have a problem with the use of concrete numeric values, try this, where "x" is the ratio between the new mass of the kilogram and the old one. The use of radical signs should make things more clear, even though I thought I'd gotten across that 0.995 here is the square root of 0.990:
this is, I believe, how the Ampere is actually defined in relation to the newton. This is not only what Ampère's force law on here says, but also what I remember from my physics text in high school. I didn't go to primary sources, but can you point out if this is incorrect - or is not how the ampere is defined? km is an invariant physical constant, whose numeric value in Nm/A² is fixed to define the Ampere. The fact that the units here include only one kilogram term, but _two_ ampere terms, is what clued me in to the fact that it's a square root relationship rather than linear. - I checked the website you linked defining the Ampere, it confirms what I say here. km is μ0/2π. --Random832 (contribs) 22:45, 12 April 2008 (UTC)
and, if
even though it’s “one meter of length for conductors one meter apart,” the force between the conductors would change non-linearly as the meter varied. - um, who said anything about the METER varying? --Random832 (contribs) 22:22, 12 April 2008 (UTC)

No one but me said anything about the meter affecting the volt. I was expanding on how the volt is unaffected by not only the magnitude of the kilogram, but also is unaffected by the magnitude of the second. As the SI is currently defined, the volt is only affected by a change in the meter.

Now I know why I didn’t understand what I was looking at with your formulas above (which started with force). Ampère's force law has nothing at all to do with how the relationship of the volt my be affected by the kilogram. Not too much analysis is required as to how the ampere is defined (though I showed the complete definition in my previous answer in the quotation box). If the objective is to determine whether or not a variation in the kilogram affects the volt, one need only satisfy themselves that it has only one kilogram term in the ampere and it’s right there in the newton (in the value 2×10−7 newton per meter of length).

So far, I detect no errors in my analysis above. What you’ve been doing in your two analyses above amount to examinations of the relationship of force and the ampere. If the question is this: “Will a change in the magnitude of the kilogram affect the magnitude of the volt(?)”, you must start with this: “How is the volt defined” and reduce the whole thing to SI base units. Start here:

  • V = WA

…and go from there. You should conclude that the newton appears only once in the watt and only once in the ampere. That’s all that is required to know that the kilogram appears only once each in the denominator and numerator (W & A) When you’re done, it should look like what I have above. If not, let me know. Greg L (my talk) 23:26, 12 April 2008 (UTC)

section break

A simplification, if you don't want to read all of the above
"A = K · 2×10−7 N" - this is where you have a "brain fart" as you put it. There are two wires, both carrying a current, and the force is proportional to the product of the two currents. The correct relationship would be A2 = K * 2×10−7 N. That's why I did the numerical analysis with 0.990 - when everything's 1, it's easy to forget where you've taken its square root. --Random832 (contribs) 22:22, 12 April 2008 (UTC)
Incidentally, this also means the farad, siemens, and henry - and any unit whose fundamental terms include A²/kg or kg/A², would not be affected. --Random832 (contribs) 22:40, 12 April 2008 (UTC)
  • Not at all. The test as to whether or not a derived unit is affected by a change in magnitude of the kilogram is whether or not the kilogram appears an equal number of times (and at the same power) in the numerator and denominator. You cited the siemens above. That is a reciprocal ohm. Look at the ohm. It doesn’t balance so both it and the seimens are affected. Pretty much all the electrical units are affected because the kilogram underpins the SI base unit of electricy: the ampere, and everything else flows from that. The notable exception is the volt. A 10% bigger kilogram doesn’t affect the volt by virtue of the fact that the newton (and therefore the kilogram) appears once each in both the watt and the ampere. Therefore, the tesla too is unaffected. Greg L (my talk) 23:48, 12 April 2008 (UTC)
The ohm, then, would _also_ be unaffected. My point this entire time is that the kilogram does NOT appear once in the ampere - it only appears one HALF time (that is, the 0.5 power - the square root - of the kilogram appears). It appears once in the ampere-squared. The ampere must appear twice as many times (or, rather, at twice the power) in the numerator as the kilogram does in the denominator, or vice versa, for it to "balance". --Random832 (contribs) 00:05, 13 April 2008 (UTC)
  • A volt is a W/A. How do you keep coming up up squares and square roots? One deals with squares and square roots primarily if you are trying to figure out a change in resistance from volts and watts, or a change in watts from amps and resistance, or a change in amps from watts and resistance. But that’s not what needs to be done here and that’s not what I’m doing but somehow seems to be what you’re doing and I don’t know why. And you’ve twice now started with Ampère's force law to somehow discern a relationship between the kilogram and the volt. One can’t possibly figure out the answer to the question using the formula you chose. The newton appears twice in the BIPM definition of the volt. The following parenthetical is the newton, expressed entirly in SI base units: (m·kg·s–2). Now let’s look at the volt, expressed entirely in SI base units. How many “kg” do you see in it below?
V = (m·kg·s–2)·m·s–1K · 2×10−7 (m·kg·s–2)
I count two. Greg L (my talk) 00:35, 13 April 2008 (UTC)
But the formula "K · 2×10−7 N" is incorrect, I pointed that out above - for your proposed "K", an ampere would be "√(K · 2×10−7 N)" - are you even paying attention to my argument? --Random832 (contribs) 00:45, 13 April 2008 (UTC)
V = (m·kg·s–2)·m·s–1√(K · 2×10−7)(m0.5·kg0.5·s–1). --Random832 (contribs) 00:49, 13 April 2008 (UTC)
you’ve twice now started with Ampère's force law to somehow discern a relationship between the kilogram and the volt. because that law is how the relationship between the kilogram and the AMPERE is defined! --Random832 (contribs) 00:52, 13 April 2008 (UTC)
  • Don’t shout and settle down. I showed you every step of the way above and you aren’t seeing it. Show your math. Just how in the world do to you start with V = WA and end up with V = W√A ? (as shown in your 00:49, 13 April 2008 (UTC) post) Greg L (my talk) 01:07, 13 April 2008 (UTC)

The problem

You've somehow convinced yourself that the definition of an ampere contains an entire newton term (instead of a N0.5), you keep using that as a premise, and you are not listening when I keep pointing out that it's wrong. --Random832 (contribs) 00:57, 13 April 2008 (UTC)

You seem to think that because this isn't one of the situations where squares come up in everyday electrical problems, that it's somehow inappropriate to be talking about square roots. The problem is, you're ignoring that the force between two current-carrying conductors (in terms of which is how the ampere is defined) is proportional to the _product_ of the two currents (when the currents are the same, the product of them is the _square_ of that value) divided by the distance between them. --Random832 (contribs) 01:03, 13 April 2008 (UTC)
  • This is not complex. The BIPM defines the volt as V = WA. I choose that definition over yours (as shown in your 00:49, 13 April 2008 (UTC) post), where V = W√A Greg L (my talk) 01:10, 13 April 2008 (UTC)
    • !!! I never said "V = W√A" Please go back and re-read my argument if you don't understand this. --Random832 (contribs) 01:22, 13 April 2008 (UTC)
    • A = √(K · 2×10−7 N), period. --Random832 (contribs) 01:19, 13 April 2008 (UTC)
  • I am too defending it; above (twice) and here again. Here is what the BIPM says about what the ampere equals.

The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2×10−7 newton per meter of length.

Please tell me just where it the BIPM says anything about the square root of the force? The BIMP says V = WA, not V = W√A Greg L (my talk) 01:25, 13 April 2008 (UTC)

  • If there is a flaw in my math or logic, it must be here. It would be terribly helpful if you didn’t redefine the first equivalency; that is after all, what the BIPM says the volt is equivalent to.
V = WA = J·s–1A = (N·m)·s–1A = (m·kg·s–2)·m·s–1A = (m·kg·s–2)·m·s–1K · 2×10−7 N = (m·kg·s–2)·m·s–1K · 2×10−7 (m·kg·s–2)
Greg L (my talk) 01:18, 13 April 2008 (UTC)
Your flaw is BEFORE that, "A = K · 2×10−7 N" is wrong and I explained that it was wrong and why it was wrong as the very first statement in my argument above. --Random832 (contribs) 01:20, 13 April 2008 (UTC)

I used proper algebraic simplification from a real starting point to arrive at "A = √(m·Nkm)" where km is a real physical constant. You waved your hands to arrive at "A = K · 2×10−7 N". --Random832 (contribs) 01:28, 13 April 2008 (UTC)

  • OK, I’ll come down here and post what the BIPM says. Please tell me where the ampere is equal to the square root of the newtons of force.

The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2×10−7 newton per meter of length.

Greg L (my talk) 01:29, 13 April 2008 (UTC)

Exactly. It's the current maintained in TWO straight parallel conductors. If the kilogram (and therefore the newton) changes, the current in BOTH conductors therefore has to change. And the Ampere force law says that the force is proportional to the product of BOTH currents (since the currents are the same, that product is the square one of the currents). --Random832 (contribs) 01:32, 13 April 2008 (UTC)

  • I’m thinking about this. Greg L (my talk) 01:37, 13 April 2008 (UTC)

P.S. An ampere is equal to a certain, small amount of force, in newtons; not the square root of newtons. Isn’t it? Greg L (my talk) 01:31, 13 April 2008 (UTC)

no, it's an ampere _squared_ (i.e. one ampere in one wire multiplied by one ampere in the other wire) that is equal to that certain small amount of force in newtons [per metre of the length of the wires, but you knew that] --Random832 (contribs) 01:37, 13 April 2008 (UTC)
For something that could be experimentally verified if you had the stuff to set up such an experiment - imagine, against all plausibility, that the kilogram (and the newton) have become four as large, and that the ampere is now defined in terms of this new super-newton. The amount of current to go through each wire to generate a force of four times as much is only twice as much, not four times. I.e. the current that needs to go through two parallel conductors to generate four (present-day) newtons of force is only two amperes, rather than four amperes. --Random832 (contribs) 01:55, 13 April 2008 (UTC)

I believe you are correct Random832. The volt and the tesla should be affected as the square root of the change in the kilogram. I wish we had found the key to communicating a bit faster. Are the volt and tesla the total extent of the effect of this? Greg L (my talk) 02:21, 13 April 2008 (UTC)

  • Random832, I corrected the article per your teachings (∆ here). Believe me, while the debate process leading up to making the correction was painful, I am very appreciative that you saw my editors note and my error of omission has been corrected (although my hidden editors note explaining why the volt and tesla weren’t included in the list was proven to be a bunch of horse crap). My primary objective is that this kilogram article be the best, most authoritative source on the kilogram there is for a general-interest readership. I’ll take intervention from someone who is right (v.s. a bone cone who messes things up) any day. Wikipedia and its readers are the beneficiaries. Thanks very much. Greg L (my talk) 02:40, 13 April 2008 (UTC)
I believe that also some other units (ohm, henry, siemens, farad and any i've missed) listed as affected would not be affected, since their terms include kg/A^2 or A^2/kg. The weber would be affected whereas the logic that excluded the volt would also exclude it, but it was already listed as affected. I've edited the article accordingly. --Random832 (contribs) 03:05, 13 April 2008 (UTC)

Number formatting

These two edits to remove “virtually uneditable” HTML code is an unsupportable position and would harm the article. If you lack the skills necessary to deal with it, then don’t deal with it. All the HTML span tags in this article are properly implemented and properly closed. Such code is important so nearly difficult-to-parse numbers like 6.02214179 × 1023 instead become properly formated, SI-compliant strings that appear like 6.02214179 × 1023.

This is the same technique as is used in Natural logarithm where the first paragraph displays the number “2.718281828459”. Are you going to haul off to that article and “fix” that article too so the displayed value is “corrected” to the un-parsable abomination of 2.71828182845? Are you going to do this so you don’t have to look at HTML code that you don’t understand?

This issue of having to resort to span tags to delimit numeric strings is currently being addressed. The issue was thoroughly discussed here at Talk:MOSNUM (it’s an archive, don’t make changes there). The consensus at Talk:MOSNUM was to make a new parser function (template) that will automate the delimiting of numbers and the parser function is currently being written. Instead of the cumbersome span-based code, the upcoming parser function will enable editors to type {{delimitnum:6.02246479|30|23|kg}} in order to obtain the following: 6.02246479(30) × 1023 kg. This article will among the first, if not the first, to use the parser function when it is available.

In the mean time, this article has been stable and for quite some time and is in no need of being rescued by well-intentioned editors. I seriously doubt either of you needed to alter any of the numeric values here so just edit around them in the mean time. Greg L (my talk) 08:34, 7 March 2008 (UTC)

First of all, calm down. There's no need to shout.
Second, it looks like MOS has outgrown its own purpose a bit lately. There is no way to make Wikipedia articles appear properly exactly right on everybody's screen and the attempts to do that usually end up causing problems for other users. If there's no standard way to achieve a visual effect you want, the best thing to do is to not have the visual effect.
The mess in the article sucks, and the benefits of having numbers spaced exactly according to the standard are negligible compared to it. And you don't need a special parser function to achieve the effect. Writing a template that can accomplish what you want is pretty much trivial. Zocky | picture popups 08:43, 7 March 2008 (UTC)
  • I am calm and I am not shouting. Your unfounded insinuation that I am does not establish you as a calm and wise voice of reason here. UPPERCASE is shouting. Underlining, as I did above, is for emphasis. You should learn computer etiquette before pretending to “correct” others. You have been a registered author for less than a year and are unqualified to make declarations like “the mess is unacceptable.” This article properly uses HTML code that is specifically supported by Wikipedia. Get familiar with it and stop deleting it wherever you encounter it. I provided links for you to read and your quick response betrays that you obviously didn’t take the time to read about what has transpired to address this issue. Greg L (my talk) 08:50, 7 March 2008 (UTC)

    P.S. Are you seriously suggesting that you are overruling a consensus on MOSNUM because you know better? Do you think that issues like getting a consistent look across many computer platforms, operating systems, and browser hasn’t been thoroughly explored? If so, then you are seriously in error; we even looked at how the delimiting method appears on an iPhone. Greg L (my talk) 09:01, 7 March 2008 (UTC)

I hate when I'm forced to do this, but if you actually bother to check my contributions, you may learn that I've been around long enough (for far far longer than one year) to know "computer etiquette", and that I'm perfectly familiar with HTML. And on things like code readability, I believe I do know better than the regular commenter on MOS, but that's another story.
As for all that "transpired to address this issue" - instead of a lot of talking, somebody should have simply solved it. Here's one way (and I needed all of 30 seconds to write the template) :{{spaced|6.022|464|79(10)|×|10<sup>23</sup>|kg}} - . A more specific template could be made, but i doubt it would save any further typing, or confusion. Zocky | picture popups 09:05, 7 March 2008 (UTC)
  • Well, I am impressed with your template skills. Tell me more about your template. How wide are the spaces? I see they are not non-breaking spaces but use pair-kerning-type effects. Greg L (my talk) 09:11, 7 March 2008 (UTC)
The spaces are .3 em, as you appear to want them, and they're not "pair-kerning-type-effects", they're exactly the same spans that you inserted manually. Zocky | picture popups 09:14, 7 March 2008 (UTC)
  • Yes, after posting the above question, I realized that I only needed to go and look at your template. I see the 0.3-em spaces. I must profess that you did that astonishingly quickly. Please read the {delimitnum} archive page; there is much more to it. The spans must actually be 0.25 em to look good on Firefox, Explorer, and Safari. Spans of 0.3 em drive some readers crazy. Different browsers treat the number 0.25 differently; some resolve the 0.05-em increment (so 0.25 looks good for those users) and Safari rounds 0.25 up to 0.3 (which looks good for those users). Also, the span following the digit 1 must be 0.2 em to not appear like a regular space. All this is being addressed by a behind-the-scenes developer with the parser function. Can you wait until then? Greg L (my talk) 09:21, 7 March 2008 (UTC)
  • Changing 0.3 to 0.25 is trivial. OTOH, changing the spaces after certain digit is wrong and should not be done. The fact that a space looks wider on your screen after "1" than after "2" is an artifact of the font you're using, and will look different on another person's screen, and will look incorrect in a font that's spaced correctly. Zocky | picture popups 09:27, 7 March 2008 (UTC)
  • (undetented) We’re not retarded Zocky. Yes, we know about things looking different to different people and we addressed all of this. You arrived late in this discussion. I’m on the Pacific coast of the U.S. and it is quite late. As you can see from an earlier discussion on Talk:MOSNUM, a great deal of give & take was required to keep everyone happy. Further, the progression of delimiting (to prevent a single dangling digit) and various other issues make this job best handled with a parser function. The hand-tuned values here look good to the various editors who participated in finding a solution. Thee of us e-mailed (bypassing Wikipedia) images of screen shots back and forth until we arrived at a solution that pulled opposing parties together. The beginnings of sharing those exchanges started here on my talk page. The hand-coded numeric strings don’t do end-of-line word wraps, look good, and are Excel-pasteable. Do you think we can leave them as is until the parser function from one of the Wikipedia developers arrives? Greg L (my talk) 09:44, 7 March 2008 (UTC)
I have a better idea: we can just make the template. So I did, see {{delimitnum}}. Let's see if it works for your testcases:
  • {{delimitnum|6.02214179|30|23|kg}}: 6.02214179(30)×1023 kg
  • {{delimitnum|1579800.298728}}: 1579800.298728
  • {{delimitnum|1.356392733||50|Hz}}: 1.356392733×1050 Hz
  • {{delimitnum|0.45359237|||kg}}: 0.45359237 kg
  • {{delimitnum|6.022461}}: 6.022461
  • {{delimitnum|6.0224613}}: 6.0224613
  • {{delimitnum|6.02246134}}: 6.02246134
  • {{delimitnum|6.022461342}}: 6.022461342
Seems to work alright, no? Zocky | picture popups 10:33, 7 March 2008 (UTC)
  • Zocky, I am very impressed with your template-writing skills (and with the way you collaborate with other editors too). As you can see from looking at all that span code in the Kilogram article, I put a lot of effort into having good looking numeric values that are Excel pasteable. And by following your progress a bit last night, I could see you reacted to this situation by putting in an equal amount of time writing a damned good looking template that can be used not only here in this article, but elsewhere too.

    I just got up after about five hours of sleep and am still a bit blurry-eyed. I don’t mind giving you the honors of replacing many of this article’s numeric strings (there are a few fractions that might not take well to the treatment). My only concern is that every single number currently in the article has been quadruple-checked and is correct. If I make the change, I plan to take the article’s code to a text editor where I can do some global search & replace to ensure strings are properly converted to your new template without changing values. If you don’t mind, I’d really like to try this out. And I suppose having an extra set of “double-checking” eyes won’t hurt after all that work you put into the template. Unless you get to it first, I should have this article converted over in the next 24 hours in an incremental process. Congratulations and thanks again. Greg L (my talk) 17:06, 7 March 2008 (UTC)

You may want to try User:Zocky/Search Box for that and do it right in the edit box (works only in FF). <disclaimer>There's a bug somewhere in it that appears very occasionally (I haven't tracked it down yet, but if "replace all" doesn't work correctly, try "replace and find next" repeatedly).</disclaimer> Zocky | picture popups 17:31, 7 March 2008 (UTC)
  • Advisory to all: Zocky put a great deal of effort into this template. It now works and Kilogram has had all applicable numeric strings converted from the old hand-coded (<span>-based) method to the {{delimitnum}} template. The update resulted in a 2.07 kB reduction in article file size and made it much easier for other editors. What Zocky did is quite an accomplishment because other template authors said a function this complex couldn’t be done with a template and really required a parser function.

    The need and proper use of this template was thoroughly discussed here at Talk:MOSNUM (it’s an archive, don’t make changes there). The near-unanimous consensus was that official MOSNUM policy should be that numeric values with five or more digits to the right of the decimal marker should be formated via this template. For those considering its use, you might brush up on the nuances of how and why it should be used at the above-mentioned archive. In a nutshell though, it allows editors to type {{delimitnum|6.02246479|30|23|kg}} in order to obtain the following: 6.02246479(30)×1023 kg. Thanks again Zocky. Greg L (my talk) 02:36, 14 March 2008 (UTC)

Spans and closed span tags

Everything there was done for a reason and was done properly. If CSS spans are not supposed to be closed, that is news to me. The occasional small spans are to keep some instances of italicized text from crowding into reference numbers. It makes the articles look better and any editor worth his salt can easily comprehend why they are there. As for closing spans with “</span>”, this is the proper way to do it. See Wikipedia_talk:Manual_of_Style_(dates_and_numbers)/Archive_94#Continuing_Discussion.2C_specifically_regarding_latest_nutshell_proposal and locate the relevant discussion portion by searching on this text string: “Shouldn't the span tags be closed”.

To save you the effort though, here is a quote from that discussion:

Splarka, if span tags are not supposed to be closed, please prove it. In fact, I proved for myself that in certain circumstances, Wikipedia isn’t forgiving and if I left unclosed span tags active, the next paragraph had the beginning of its first line indented 0.25-em. Only after that new paragraph would the span cancel itself. Other weird effects can happen if you don’t close spans with a like number of close-spans. This is good practice according to Aluvus (above quote) and from my own experience.

If you don’t believe me, check out this example text copied from Kilogram but where I stripped out the close-spans from the numeric delimiting:

In everyday usage, the mass of an object in kilograms is often referred to as its weight, although strictly speaking the weight of an object is the gravitational force on it, measured in newtons (see also Kilogram-force). Similarly, the avoirdupois pound, used in both the Imperial system and U.S. customary units, is a unit of mass and its related unit of force is the pound-force. The avoirdupois pound is defined as exactly 0.45359237 kg, making one kilogram approximately equal to 2.205 avoirdupois pounds.
Many units in the SI system are defined relative to the kilogram so its stability is important. After the International Prototype Kilogram had been found to vary in mass over time, the International Committee for Weights and Measures (known also by its French-language initials CIPM) recommended in 2005 that the kilogram be redefined in terms of fundamental constants of nature.

Note how this paragraph and the second paragraph above both have indented beginnings due to two unclosed span tags from the preceeding paragraph propogating through. All spans in the article are there for a reason and all spans must be closed. Please stop deleting them. Greg L (my talk) 08:14, 8 March 2008 (UTC)


I don't think the glossary section is needed; isn't that what Wiktionary is for? Besides, Wikipedia's an encyclopedia, not a book. I've never seen an encyclopedia with a glossary at the end of every article. Wouldn't wikilinks take care of any confusion about meanings? --Gawaxay (talk contribs count) 22:24, 8 March 2008 (UTC)

  • This article had been edited by a good half-dozen editors for a long time and no one even raised the issue once; its virtues are obvious. I think you are framing the question the wrong way. Instead of whether you’ve seen it before in Wikipedia, the question should be “does it serve a good purpose and is it a good thing?” Fine, you don’t think so. However, the discipline of metrology uses terminology unique to the field. The word “prototype” for instance, has a vastly different meaning to engineers and machine designers vs. what people who specialize in the kilogram understand it to mean. It makes absolutely no sense to direct readers to an all-purpose, separate venue (Wiktionary) to look up words that have multiple, discipline-dependent meanings when a glossary with the precise, very specific meaning(s) can be imbedded right where they’re needed. Even within the field of metrology and the kilogram, the word “prototype” has three possible meanings. Trying to shoehorn all these nuanced, application-specific meanings into a general-purpose tool like Wiktionary is no way to do things.

    Note too that the definitions in the glossary are internally referential. For instance, a term like “Primary national standard” can mean “A replica of the IPK possessed by a nation.”  Well, what is a “replica” and what is the “IPK”? With the glossary, reader can instantly see these other definitions. With Wiktionary, you’d be bouncing around forever and would have to keep written notes to keep in all straight. Either that, or you’d have to have exceptionally long definitions in Wiktionary so that every unique term in the definition was itself further defined. Clearly, that is not a suitable approach. The terms used by those in professional metrology constitutes a little subset language of its own and has to be grouped together in one convenient place if you want to make it easiest for readers to quickly and conveniently understand it all. If you read beyond the section heading (“Glossary”) and take the time to read and understand the definitions and interdependencies, its virtues are obvious on the face of it. The hidden editors note at the top of the current glossary conveys this point well enough:

Greg L (my talk) 01:50, 9 March 2008 (UTC)

No longer a B-class article

This article has been greatly improved in the past year or so, and I think it should now be classified as an A class article. Personally, I think that the language is a still a bit dense in places, that the "Stability of the International Prototype Kilogram" and "Importance of the kilogram" sections have too much in common, that there are far too many comments for editors in the text, and that some of the notes are far too long and conversational. However, this really is a good article, and, while having B-class vital articles is a bad thing, I don't think that this article reflects poorly on Wikipedia at all. In fact, I think it reflects very well on Wikipedia. We can just list the article as "A" class in the Wikiproject Physics project, if others agree with me. I took a look at the Version 1.0 page, and I'm not sure what needs to be done to re-class the article for those purposes.

The next thing to do to improve this article is a Wikipedia peer review, and then it should be nominated to be a good article. If this route is taken, it makes sense to wait to re-class the article until after the peer review.

However, I'm not willing to spend the time and energy to shepherd this article through those processes, and I don't think I've corrected any vandalism or improved edits on this article in a long time (I just did a quick read through and a few edits), so I'm planning on removing this article from my watch list.

Suffice to say that kilogram doesn't need my help any more! - Enuja (talk) 02:21, 9 March 2008 (UTC)

  • I’m pleased you feel that way Enuja. As for nominations of any sort, I don’t look forward to that at all. It doesn’t benefit readers much that I can tell. In my opinion, “good article” is principally a gold star for some authors to feel good about themselves and maybe some other reasons that only certain long-time editors might appreciate. Personally, just going through the Featured Picture nomination process (one win, one loss) was so thoroughly distasteful that I never want to do it again. Featured Picture is simply a venue that some—I’m not saying all—editors use as a soap box to stand on and show what good taste they have by demonstrating how damned critical they can be of ridiculously trivial points (like “it was saved as a JPEG, and not a blankety-blank file type). I think I’d just as soon put on tire chains on a summit pass in a blizzard laying on my back in slush with frozen fingers (I did that once), than watch—or worse yet—participate in some sort of peer review.

    Simply knowing that my efforts have contributed to winning you over as an admirer of this article is all the reward I need. You’ve been tough and critical and have forced me to keep my text as tight and succinct as possible. This article, and Wikipedia in turn, has benefited from your input. I hope we can just leave it at that.

    I’m glad that you don’t have the energy to shepherd Kilogram through the peer review process. I’m heading into a 12-pig study on a medical device here in a few weeks and don’t need an enjoyable hobby turned into a energy-sapping nightmare. Suffice to say, my energy level for shepherding this article through the peer review process is between zero and reciprocal-infinity. Greg L (my talk) 02:58, 9 March 2008 (UTC)

Okay, I just noticed that the assessment scale page I was looking at is actually at Wikipedia:Version 1.0 Editorial Team/Assessment so, yeah, as involved editors we can certainly change the rating of the article ourselves to "A", so that's what I've done. I'll argue that rating articles as not needing radical revision is really important. In other words since this article is much better, it should be classified as an A class instead of a B class article. I honestly couldn't care less about GA or FA status for this article, even though I might want the shiny button of shepharding an article to FA status someday, it will be an article that I have more personal interest in the subject of. - Enuja (talk) 04:33, 9 March 2008 (UTC)

“So far lost” (days elapsed times factor)

I’ve provided this mostly for my own personal interest but it should be of interest for others. At Importance of the kilogram, there is a paragraph showing how the IPK has “likely already lost 6.6 micrograms.”  That number is a template-generated, auto-updating value that will eventually increment in the near future. Shown below is that value with excess precision so one can see when it is getting close to incrementing another count:

To save you the trouble of having to click on [edit], the template is coded as {{days elapsed times factor|1989|7|1|0.0006434|1}}, which parses as {{ Days elapsed times factor | Year | Month | Day | Factor | Decimal places }}. Essentially, this template increments the value one count every 155 days. As of this writing, the value will increment from 4.5 to 4.6 at 00:00 on 10 Nov 2008 (UTC). Many thanks to Random832 for this template.

Greg L (talk) 21:22, 12 August 2008 (UTC)

Proposed article split

I'd like to split the "Proposed future definitions" section into its own article, perhaps "Proposed definitions of the kilogram". The new article would be able to focus entirely on the various theoretical possibilities, and this article would become smaller and more focussed on the practical aspect of the unit. Thoughts? Sheffield Steeltalkstalk 18:55, 2 April 2008 (UTC)

  • SheffieldSteel, there would be quite a lot of overlap between two separate articles that talk about the existing kilogram (the IPK) and the alternative definitions because they are so intertwined. It’s easy enough to simply not read the last section of the Kilogram article rather than either 1) duplicate the Stability…, Importance of the kilogram, and Glossary sections across the two articles, or 2) put what would amount to a “Continue to page 2” link directing a reader to an article discussing only the alternative definitions kilograms. Besides, the entire Mass versus weight used to be part of Kilogram at one point (I wrote most of that). A lot of other editors weighed in (no pun intended) on moving that section to a separate article and all seemed to be quite content with the content of Kilogram after that split. When you think about it, the topic of mass v.s. weight really can—and should—be an stand-alone article. But given all the lead up required to explain the need for the new definitions of the kilogram, it would be awkward to bifurcate what is really a single topic. Greg L (my talk) 23:28, 9 April 2008 (UTC)
That's perfectly okay. I wasn't about to climb the Reichstag over this. I just wondered if 'new definitions' was actually a separate topic. Sheffield Steeltalkstalk 21:32, 11 April 2008 (UTC)

Le Grand K

There as been a bit of a Revert War between Greg L and me over my insertion of "Le Grand K". Greg claims the following when I said it is used in other parts of the English-speaking world: "As a matter of fact, I DO know that the rest of the English-speaking world doesn't use that terminology. Please read ALL the below-cited references and stop reading too much into the LA Times". A rather silly statement, if you ask me. No one on the planet, expert in linguistics or otherwise, could make such a claim. And the claim is verifiably false. A simple Google search will yield hundreds (maybe even thousands) of _English_ articles written by professionals (journalists and academics) and published in respected and/or well-circulated newspapers, journals, etc (and not just the "LA Times", which I rarely, if ever, read). I must say that I am surprised that I would have to debate this with a seemingly seasoned editor. The reasons for keeping "Le Grand K" in the article should be obvious and there are thousands of examples all over the English Wikipedia to give precedent. Look at any country article and you will see both the English name and the local language name (and any other variation) of the country in question. Look at the list of French phrases many of us use in every day English to see that calling the IPK "Le Grand K" is not unique or unheard of. It is very much used in the English-speaking circles I move in (academics). One of my professors (from America) used it in our Physical Chemistry class (and never mentioned "IPK"). If someone reads or hears "Le Grand K" in an English setting and wants to look it up in Wikipedia, I doubt they will turn to the French version of the kilogram article. Le Grand K should stay. --Thorwald (talk) 23:00, 21 April 2008 (UTC)

  • The issue is notability and relevance of the citations. You are throwing around wild generalizations about how common it is in the English language but I see no citations. Not a single one of the publications from the BIPM, NIST, CGPM and the Journal of Research of the National Institute of Standards and Technology and elsewhere that were cited in this article use Le Grand K. That is an French-language term. I don’t care what your professor used in a lecture. Cite a notable English-language scientific paper that uses it. I’ll leave your addition in on the assumption that you’ll find something. Greg L (talk) 00:36, 22 April 2008 (UTC)
    I could go on and on with many more references (all in English), but I think you get the point and could have done the research yourself. It is easy to throw around your "hogwash" statements, but they hold no sway on me. Every time you remove it, I shall restore it. There are many, many French-language terms most English-speakers use every day and they appear in the English Wikiepdia. --Thorwald (talk) 01:00, 22 April 2008 (UTC)
  • Fine. I agree. Due to that term’s not-infrequent use in English-language articles directed to a general-interest readership, it is appropriate to mention that it is also known as the Le Grand K. Greg L (talk) 01:38, 22 April 2008 (UTC)

Possible Source Error

They concluded that one cubic decimeter of water at its maximum density was equal to 99.92072% of the mass of the provisional kilogram made four years earlier. - There may be an error in the original source here. Will someone please check me on this reasoning -- For two equal volumes of equal types of matter at different temperatures, the volume of the higher density will contain more mass. Therefore, one liter of water at maximum density (~4c) should have more mass than one liter of water at maximum temperature stability (~0c). The source states instead that the higher density (4c) equal volume of water has 99.92072% the mass of one liter at (0c). (it "weighs less"). Could the original source have these ratio inverted? Thanks. Drakcap (talk) 03:30, 7 May 2008 (UTC)

  • Indeed, I hadn’t noticed that. Either the researchers who made the provisional kilogram in 1795 were off by quite a bit, or the cited source has their percentage reciprocated. The density of water at 0 °C is 999.8395 kg/m3 and at 3.984 °C, is 999.97495 kg/m3. So one would expect that if the researchers had accurately made the provisional kilogram to equal a cubic decimeter of water at its ice point, a cubic decimeter of water at 4 °C would have a mass that is 100.013547% that of the provisional kilogram. The reciprocal of this is 99.98645% (compare to the cited 99.92072%). The linked Web site cites Richard Steiner (who is currently working on the watt balance for the NIST) and Dr. Terry Quinn, who used to head the BIPM and who authored a book on the kilogram; these are two heavy hitters on the kilogram and I’ve e-mailed them both many times during the writing of this article. I just e-mailed Dr. Quinn about this. My guess is that since it was a “provisional” kilogram that was just banged out without the benefit of any of the years of research on the true density of water, it simply hadn’t been made accurately. If that proves to be the case, I’ll expand the footnote to clarify this point. Thanks. Greg L (talk) 20:03, 7 May 2008 (UTC)
  • I just e-mailed Dr. Quinn again. He was busy the first time and just heading out the door and I think he forgot. We’ll get to the bottom of this. Greg L (talk) 22:18, 11 June 2008 (UTC)
  • There. Addressed (here in note #8). It was a crappy earlier measurement of the density of 0 °C water that lead to an over-weight provisional kilogram. Greg L (talk) 19:53, 7 August 2008 (UTC)

Historical concerns about stability of standard weights

I found this 1910 article about a test in which the US standard troy pound was found to have increased in mass by .007 grain (450 µg/1.2 ppm) and it made me think that it might be useful to add a brief section about the historical perspective of concerns about mass standards losing or gaining mass - anyone know if there are any similarly old articles concerning the kilogram itself? --Random832 (contribs) 14:46, 25 July 2008 (UTC)

  • “It might be useful to add a brief section about the historical perspective of concerns about mass standards losing or gaining mass” Random832, have you read the current article? I would think that Stability of the International Prototype Kilogram would be enough of a treatment on the subject of instability in mass standards. The current treatment begins in 1889. Greg L (talk) 17:23, 25 July 2008 (UTC)
  • P.S. The scientists in 1910 declared the proper, scientifically valid conclusion: the 0.007-grain change in documented mass was “negligible” and within the tolerances. Further, the New York Times’ headline that it “gained weight” was not in error, unlike what has recently been reported in the popular press that the IPK “lost 50 µg”. As the NY Times article correctly pointed out, the pound standard that was being weighed in 1910 was A) made of brass that had seriously oxidized and had never been polished or cleaned. It was now a slightly purple, smokey deep green. And B) it was being weighed for the first time relative to new mass standards at what is today the NIST and those standards had without a doubt been calibrated relative to K4, the U.S.’s platinum-iridium prototype, which had been allocated to the U.S. in 21 years earlier 1889. Further, the brass pound standard was being weighed on a then-new, highly accurate type of scale, the Rueprecht Balance. The only conclusions that could be made is that 1) due to obvious oxidation, the brass standard must certainly have gained some mass after first being manufactured (an issue that was obvious and clear at that time), and 2) exactly how much it gained can not be known with any certainty since no calibration trail to a single, highly stable mass artifact had been maintained and no mass comparison could be made to an invariant of nature at the necessary level of precision. Accordingly, it can not correctly be stated that the pound artifact gained 0.007 grain, only that its documented mass changed by that amount. Greg L (talk) 17:58, 25 July 2008 (UTC)

Problems with weighing

When you're weighing something you have to be careful about the process. Say you take a sealed container with a 1kg weight inside and weigh it, and then remove the weight and then weigh it again (for tare measurement), and then say the difference is the weight of the 1kg weight, and you would be wrong. And the error would be the weight of the volume of air (or whatever) displaced by the 1kg weight. So how do they keep track of that and correct for it?WFPM (talk) 17:15, 24 August 2009 (UTC)PS I don't know about the air buoyancy problem; but if the container were vacuum sealed during both the initial weighing and the tare weighing process, that would help solving the air weight problem.WFPM (talk) 18:03, 24 August 2009 (UTC)


Just letting you know that Milligram redirects here, when it would be better if it redirects to gram. :) Intothewoods29 (talk) 20:32, 8 August 2008 (UTC)

Mass is the only dimension where the base SI unit has a prefix - so we have seconds, metres, and kilograms. While it seems strange, this is the right article for other unit articles to link to. That's my understanding anyway. SHEFFIELDSTEELTALK 21:43, 8 August 2008 (UTC)
Yes. Though either Kilogram or Gram would work fine with me, the more complete article (Kilogram) is probably better. Although I must say, typing “milligram” and ending up on an article as if one had typed “kilogram” does seem a bit strange compared to just leaving off the prefix and going to the root unit “gram”. But I also see that “centigram” redirects here too. So for consistency, completeness, and since—as SheffieldStee wrote above—the kilogram is actually the base unit of mass for the SI system (notwithstanding that it has a prefix as part of its name), it’s probably better to redirect here. Greg L (talk) 03:58, 9 August 2008 (UTC)

Citation template linking to year

Hi Greg! You're really doing excellent work here! I did end up reverting one of your edits, though: I put back the book citation template for the Hall citation, even though it produces a link to the year 1964. Citation templates make it easier to keep a uniform citation style throughout Wikipedia, and greatly ease updates to citation style. If you don't think it's appropriate to link bare years in citations, that is a reasonable point of view, and one for which I have much sympathy, but one which should really be sorted out at Template:cite book. --Slashme (talk) 11:23, 11 August 2008 (UTC)

  • Thank you for the ‘ata boy.’ As regards the cite template, very well. I responded in depth on your talk page here. Greg L (talk) 03:49, 12 August 2008 (UTC)

I figured it out: use "year" instead of "date" as the parameter and it doesn't get linked. --Slashme (talk) 05:57, 12 August 2008 (UTC)

  • Fabulous. Thanks. I appreciate your valuable edits and help here. Greg L (talk) 21:00, 12 August 2008 (UTC)

Alloy designations

LeadSongDog, thanks for your help. But as a card-carrying member of ASM (formerly known as the American Society for Metals), I am quite certain there is no percent sign in alloy designations, such as the ubiquitous titanium alloy Ti-6Al-4V. But your edit speaks to how cryptic terminology shouldn’t be introduced abruptly without proper introduction. I have revised to better lead into the notation. If readers are to be introduced to the world of metallurgy, they need to be properly exposed to the most basic terminology metalurgists use.

As of this morning, here is the ∆ to Kilogram as a result of your, my, and Tifoo’s efforts over a period of only 17 hours. The article slowly gets better and better. It gives one a real appreciation for how the experts can put together huge professional encyclopedias in perma-ink on paper and have so few errors. Greg L (talk) 18:17, 22 September 2008 (UTC)

The cited source, describing the "International Prototype and Prototypes Numbered 1 to 63", says it this way:
It's more or less readable from a google OCR'd scan: [1]LeadSongDog (talk) 19:43, 22 September 2008 (UTC)

  • Sure. We’re both right. When describing and discussing alloy contents, which this article does in three places, it is perfectly OK to use percents and the percent symbol; for instance where it says “…which is 90% platinum and 10% iridium (by weight)”. All I’m saying is that when one uses the “Pt-10Ir” alloy-style notation of metallurgists, one leaves off the percent symbols. It is not “Pt-10%Ir” nor is it “Ti-6%Al-4%V”; it’s not done that way in metallurgy. Greg L (talk) 20:56, 22 September 2008 (UTC)

Understood, but we're writing for a general readership, not just for metallurgy historians who know the notation forms used in the 1870s and today;/) The source gives the metallurgy some human dimension. Given that the choice of alloy is now (retrospectively) seen as possibly contributing to mass drift (due to airborne Hg affinity) an attribution may be of interest to readers. You be the judge.LeadSongDog (talk) 21:53, 22 September 2008 (UTC)

  • The two existing citations I provided to that paper (#11 as of this writing), are cited in a paragraph that already uses the plain-speak you are advocating:
The IPK is made of a platinum alloy known as “Pt‑10Ir”, which is 90% platinum and 10% iridium (by weight) and is machined into a right-circular cylinder (height = diameter) of 39.17 mm to minimize its surface area.[1]
  1. ^ New Techniques in the Manufacture of Platinum-Iridium Mass Standards, T. J. Quinn, Platinum Metals Rev., 1986, 30, (2), pp. 74–79
This sort of plain-speak (with the percentages spelled out using the % symbol) are used later in the article too. It is only later on in the article that the succinct, metallurgist-style notation “Pt‑10Ir” are used. And they are used only after a proper introduction (twice). But when they are used, they are shown in their proper form (without percentage symbols), just like Ti‑6Al‑4V. Note too that if one is within a lengthy list of alloys of a particular element—such as within a handbook of titanium alloys—one dispenses with the preceding “Ti” and just writes “6Al‑4V” (pronounced as “six ay el four vee”). This article isn’t a lengthy discussion of various platinum alloys so it wouldn’t be appropriate to just describe the alloy as simply “10Ir” here.

I am only saying that it is great to write “90% platinum and 10% iridium” in the article (which it does), but where it uses the succinct metallurgist-style notation, we mustn’t bastardize them with percent symbols. That’s all. Greg L (talk) 18:36, 23 September 2008 (UTC)

I just realized that I never replied on this. It looks reasonable. Thank you for the explication.LeadSongDog (talk) 19:04, 30 September 2008 (UTC)

lowercase "kilogram" vice "Kilogram"

It was recently put by user:Indefatigable that upper case is perfectly acceptible in the title. I would argue that even if it is, lowercase is the better and more appropriate choice to avoid misleading readers into thinking it is always in capitals.LeadSongDog (talk) 19:36, 24 September 2008 (UTC)

  • LeadSongDog, if this article was an island all by itself, I wouldn’t much care if it the article title was capitalized or not (Kilogram or kilogram). Were it me defining how Wikipedia ought to work, I might have done it like World Book, which puts article titles in all uppercase. However, this is Wikipedia and it has its own conventions for doing things. With very rare exception, Wikipedia article titles are capitalized. Why? Because MOS:Article titles says this on the issue:

The initial letter of a title is capitalized (except in very rare cases, such as eBay). Otherwise, capital letters are used only where implied by normal capitalization rules (Funding of UNESCO projects, not Funding of UNESCO Projects).

I note too, this notable exception: iPhone is also not capitalized. So your edit begs this question: is “kilogram” a special case like “eBay” and “iPhone” are? I think Indefatigable is clearly correct here. The article title has long been capitalized and I hadn’t noticed that you changed it seven days ago. Your argument, that this article should be an exception to the rule to avoid misleading readers into thinking that “kilogram” should always be capitalized doesn’t withstand scrutiny since virtually all article titles on Wikipedia are capitalized. Further, the second word of the body text makes it clear that that the proper unit name is not capitalized. I see no compelling reason (not even a non-compelling one) that this article’s title should be any different from that used for Gram, Newton, and Pound (mass). Oh… and Kilometer, which I see you had changed too. Greg L (talk) 02:34, 25 September 2008 (UTC)

Capitalizing the article title. And “why does this article use “meter” v.s. “metre?”

That same section first says

Article titles should conform to Wikipedia's naming conventions, including "Use English".

So consulting naming conventions we find this instruction to consult major dictionaries. Going to the three suggested and searching for the caps version using US spelling we find ([2] [3] [4]) consistent use of lowercase in preference to caps. Also, checking Britannica Online we find the same thing. We also find that Britannica and Oxford speak directly to the existence of the alternative US spelling "-er" whereas Webster and American Heritage omit mention of the "-re" spelling. What justifies us inventing custom behaviour for WP? LeadSongDog (talk) 20:30, 28 September 2008 (UTC)

  • Sheesh, you are nothing if not persistent LeadSongDog. Wasn’t our first go around here on my talk page convincing enough for you?

    First issue: Using sentence-case for the article title. This issue has to do with the sentence-case used for the article title: “Kilogram” and not “kilogram”. You changed it and then Indefatigable changed it back. We discussed this but you’re here again, with “proof” that this article’s title should be lowercase because the various dictionaries you’ve cited above show the word is not capitalized. That’s absurd.

    The word “kilogram” is not a proper noun and is not capitalized unless it starts a sentence or is being used as a rubric in title-case, sentence-case, or all-cap. My print edition of the World Book dictionary uses all-caps for entires. I’ve yet to find anyone who is confused by World Book and thinks all words are supposed to be spelled out in uppercase, like “KILOGRAM”. Wikipedia’s article titles use sentence capitalization (Kilogram). Do you think this practice is unwise because it’s confusing to some special breed of moron that frequents Wikipedia?

    Don’t complain to me and stop hounding way on this issue; I didn’t set the convention used on Wikipedia. Why are you even arguing this point here? Do you think someone died and made me Boss, with the power to influence Wikipedia’s article title style convention? We’re not going to have you wading into Wikipedia’s Kilogram and Kilometre articles and changing them all to lowercase[5][6] (so they join the ranks of the special exceptions like eBay and iPhone). They are not exceptions to the rule. And all your citings above, showing that the word is lower-case is absurd; this is strictly an issue of the convention used in article titles.

    So let’s examine the wisdom of Wikipedia’s convention. One could legitimately ask “Is Wikipedia’s convention inconvenient because it obscures proper nouns?” Perhaps. But the second word in the body text makes it clear as glass that the word is not a proper noun. So no one with an I.Q. bigger than their shoe size is going to be confused. I see no need to change Wikipedia’s convention and the effort to do so certainly isn’t going to start here. End of story.

    Then the second issue: The spelling of words like “meter” and “liter” in the Kilogram article. Why use American English? Just one reason LeadSongDog: Because according to MOS:Consistency:

If an article has been stable in a given style, it should not be converted without a reason that goes beyond mere choice of style. When it is unclear whether an article has been stable, defer to the style used by the first major contributor.

So let’s establish some facts. Has this article been stable using one dialect of English? This is the first version of the Kilogram article. Note the spelling of “liter” (not litre) and “gram” (not gramme); the article was first written in American English. That author, User:Mike dill is an American. Then let’s examine whether I have been a major contributor. This is what the article looked like on 8 March 2007, just before I started revising it. At that time, it was small, was organized like a piece of crap, had only one illustration, and had too many errors to shake a stick at—some of them glaring. And here is what it looked like 227 days later, on 21 October 2007. So I am the the first major contributor to the current version. I am American and use American English. Therefore, per MOS, the article has been stable in a given style, and I am the first major contributor. On both counts, this article, according to MOS guidelines, should stay as it is.

The second issue to be explored is whether “meter” and “kilometer” are American-English spellings. Note that Wikipedia:Naming conventions (precision)#Conflicts over precision mentions that editors should look towards the “most authoritative” encyclopedias, including American Heritage. Well, I happen to own the full, unabridged version of American Heritage Dictionary. It states this regarding “metre”:

n. Chiefly British
  Variant of meter.

and under “meter”, it says this:

n. Abr. m
  The international standard unit of length, approximately equal… [blah, blah, etc.].

I also own World Book Dictionary, and Webster’s New World College Dictionary. Same spelling in those too.
OK, so maybe you might concede that the unit is spelled “meter” in American English but you might argue that this doesn’t prove it’s a *correct* or *proper* practice. Well… please note that when it comes to how the unit is officially spelled in the the U.S., the NIST follows the practices prescribed in the United States Government Printing Office Style Manual, which follows the country-wide practices observed in the U.S.: “meter”. At the NIST Guide to the SI, it states as follows:

• the spelling of English-language words - for example, "meter," "liter," and "deka" are used instead of "metre," "litre," and "deca" - is in accordance with the United States Government Printing Office Style Manual [3], which follows Webster's Third New International Dictionary rather than the Oxford Dictionary used in many English-speaking countries. This spelling also reflects recommended United States practice (see Secs. C.1 and C.5);

Now, I pointed this out to you earlier on my talk page. I quoted the above text from the NIST Guide to the SI explaining how for British-dialect English, an example dictionary to look to would be the Oxford Dictionary. And for American-dialect English, one would look to a dictionary like Webster's Third New International Dictionary. Yet here your are again, harping on this same issue. This debate is entirely unnecessary.

Clearly, the NIST simply follows the BIPM with regard to definitions, and observes common U.S. practices when it comes to spelling. Once again, this is clearly a dialect issue and nothing more. It is not an issue of right or wrong. If you want to change MOS policy, go lobby to have it changed on WT:MOS. Personally, I think the current policy is wise, as it encourages editors to roll up their sleeves and make meaningful contributions and it prohibits editors from wading into articles that others have slaved over just to change spelling on some words because they think their dialect of English should hold dominion over planet Earth. Such editwarring was found to be discouraging and took much of the fun out of the hobby of contributing to Wikipedia.

Now… Please stop hounding away on this issue, arguing that, somehow, British English is the only dialect of English that is *correct*, and that British English is the only dialect that isn’t confusing on Wikipedia, and that the only *official* spellings are British English, which have been beatified by the Pope and anointed with holy oils. The British weren’t even involved in inventing the meter; the translations from French are purely a matter of style. Do you think you should get your way because you guys have James Bond?

Finally, your last rhetorical question in your post above, “What justifies us inventing custom behaviour for WP?” is utterly fallacious. In case you haven’t yet figured it out, I am not inventing the spellings “kilogram”, “meter”, nor “liter” (or for that matter “behavior”, “color”, and “realize”). And if you think titling this article “Kilogram” (uppercase) is “custom behavior”, then I think I’ll back away slowly (*sound of uncomfortable side-step shuffling*)  and go back to my universe now… Greg L (talk) 02:01, 29 September 2008 (UTC)

(ec)Let's just back up a moment here. First off, I'll thank you for your recognition of persistence, coming from a master such as yourself. However, your assumption that I'm British is incorrect (although I have visited there for about two weeks of my life, I've spent waaaay more time in the US, both physically and virtually present.) I recognize the fact that you have been the largest contributor to this article, which is the main reason for engaging so much energy in this discussion with you. I'd like to pursuade you that there is merit in having systemic consistency across the SI metrology articles, not just within this one. Clearly I got off on the wrong foot with my edits, but that doesn't mean I should give it up.

The "-re" spellings are used in (nearly?) every major version of English except US English, including Indian English, Pakistani English, South African English, Australian English, and Canadian English, not to mention being used in the original French text of the Convention (albeit with an accent and with allcaps title). The American Heritage Dictionary may be an authority on American English, and I am impressed that you took the time to compare the print version, but clearly it is not a principal authority on other variations of English. To reciprocate, I'll consult my Concise Oxford, where I find

meter1 n., & v.t. 1. n. person or thing that measures esp. instrument for recording quantity supplied (GAS, WATER, meter) or present (humidity meter) or needed (exposure meter); = PARKing-meter, TAXIMETER; ~maid, woman employed to report offences gainst parking-meter regulations. 2. v.t. measure by meter. [ME, f. METE + -ER]
*meter2,3. See METRE1,2

Perhaps that makes it a little clearer why the "meter" spelling is such a precarious matter for English-speaking aliens? ;/)As I've tried to make clear, it's not a question of style per se, but of unnecessary ambiguity. In regards to the use of caps, if you check pages that link to Template:Lowercase you'll see that there are over 4000 of them, including many technical terms and SI prefixes (from yocto- to yotta-). The kilo- article varies from the pattern, and even from wikt:kilo-, which uses lowercase. (You'll note that I had nothing to do with that Wiktionary entry.) See also Talk:Peta-, another article with which I had nothing to do. Lowercase is both the correct, standard-compliant form and the conventional thing to do here. If we look to US sources, page 8 of "63 FR 40334-40340" has

3. When the name of a unit is spelled out, it is always written with a lowercase initial letter unless it begins a sentence. (my emphasis)

examine page 18 of NIST's SP330, we see how they neatly avoided using unit names as section titles by adopting the formulation "Unit of mass (kilogram)". That approach might cut the Gordian knot on the use of caps in the title, but it isn't exactly in line with WP practice for article titles either. LeadSongDog (talk) 22:00, 29 September 2008 (UTC)
Hmm. I think you've hit the nail on the head, LeadSongDog. WP has a practice for the capitalization of article titles, you can find it at WP:NAME#Lowercase: first word always capitalized, second and subsequent words in lower case unless they would otherwise be capitalized in a normal English sentence (eg, proper nouns, trade marks, other exceptions). {{Lowercase}} was introduced to deal with hard cases such as eBay or pH – it may become more standard practice in the future (Wiktionary has always had lowercase titles), but it hasn't yet. Insisting on a lower case first letter for kilogram, an article titled with a (very) common noun, is simply WP:POINT. You should take this discussion to WT:NC. Physchim62 (talk) 22:28, 29 September 2008 (UTC)
  • LeadSongDog. Ok, I understand. There are many dialects of English, such as Pakistani English and only one (American English) has a word with a dual meaning that spells the international unit of length identically to the measuring instrument. Fortunately, this article doesn’t use the word “meter” to mean the measuring instrument; the word here has only one meaning: the unit of length. Across the entire Wikipedia project, I don’t see this as a relative shortcoming however; I’m quite certain that American English isn’t the only dialect that has words with dual meanings.

    Whereas I do see some virtue in keeping dialect consistency across metrology-related articles on Wikipedia, I see the virtues as tenuous. Just as compelling an argument can be made that Americans—who are slowly being dragged kicking & screaming into the metric system—shouldn’t have to wonder if they’ve been redirected to a British version of Wikipedia when they try to research an article on the kilogram (“you realise, of course, that you should take your colourful, ten-kilogramme, two-metre-long bouquet and store it in the boot).” I think we all really should be a bit more tolerant of everyone else’s dialects, with their quirky homonyms and words that have dual meanings. I think the confusion you are alluding to is A) a two-way street, and B) is a problem that is more imaginary than real. Greg L (talk) 02:29, 30 September 2008 (UTC)

  • Nice. How about "you are aware that your beautiful 2 m flowers would be safer stowed than carried inside the cab?" It's usually not that difficult to find a usage that end-runs the homonyms...;/) Anyhow, in light of your wish to see this discussion go elsewhere, I've posed the caps question at Wikipedia talk:WikiProject Measurement. If you feel like continuing it, that is probably a more appropriate venue. Perhaps we can agree to let the "-er" vs "-re" question stand on the back burner for now. LeadSongDog (talk) 17:28, 30 September 2008 (UTC)

When you're writing about an international standard unit of measurement, surely that would prompt your common sense and make you write words with the correct spelling. It's completely absurd that we have "meter", "liter" etc in this article, let alone any article of an encyclopaedia. —Preceding unsigned comment added by Huey45 (talkcontribs) 12:50, 5 November 2009 (UTC)

Good article nomination

I think I'm sufficiently uninvolved on this article to nominate it for WP:GA status, so I have done. Congrats to all editors who have helped to improve it. Physchim62 (talk) 20:17, 30 September 2008 (UTC)

GA Review

This review is transcluded from Talk:Kilogram/GA1. The edit link for this section can be used to add comments to the review.

GA review – see WP:WIAGA for criteria

  1. Is it reasonably well written?
    A. Prose quality:
    The note in parentheses about relativistic mass (in "The nature of mass" is probably not necessary, as it's not really relevant to the topic, and it may give the reader an incorrect understanding of relativistic mass.
    • Hmm, the statement seems correct to me, and the increase in observed (and not "invariant") inertial mass at high relative speeds is fairly well known: so well known that it isn't even mentioned in articles such as Special relativity (GA) or Consequences of special relativity. There is an article, Mass in special relativity, which could be linked to and which describes the pedagogic problems of variant mass. However, I think it's necessary to have a short section on the nature of mass in the article, simply because sometimes it is counterintuitive. Physchim62 (talk) 17:59, 2 October 2008 (UTC)
    • Indeed. The issue of relativistic effect on mass is quite germane to the issue of mass constancy. Without this text, there had been ediit warring over the issue because the notion of mass constancy was incomplete. The article has been stable and correct with it. Greg L (talk) 20:10, 2 October 2008 (UTC)
    When I first read it, I had assumed it was referring to (invariant) rest mass, so I think linking to the Mass in special relativity article, and maybe rewording it to make it more clear what is intended, will help. - Algorerhythms (talk) 20:16, 2 October 2008 (UTC)
    • Done. Thanks. That is a much more suitable article; I didn’t know it existed. Greg L (talk) 20:35, 2 October 2008 (UTC)
    B. MoS compliance:
    In "Early definitions", the Notable Events of 1795 link is not necessary, and should probably be removed. In addition, there are a couple "See also"s in the text that can be turned into links (specifically, there's a "See watt balance below" link, when watt balance is linked in the previous sentence.) In addition, you may want to change the references template to Template:reflist rather than <references/>, since there are a large number of references for the article.
    • The notes section is more than a list of citations that aren’t intended to be read (such as the References section of the United States of America  article). Here on Kilogram, instead of just citations, there are notes that provide supplemental reading. Small text, particularly the italicized portions, is extremely hard to read on certain browser/OS combinations and this is aggravated by the fact that this article uses quite a few superscripted numbers—an issue that doesn’t affect normal citations. Yes, the section is expansive, but it is  at the bottom—where it stays out of the way—and the text and those numbers are much easier to read in normal-size text.

      As for the link date to 1795, that was a demonstrated technique to use as a paradigm in making a point in an ongoing MOSNUM debate. Agreed. Best leave Kilogram out of it. Greg L (talk) 20:22, 2 October 2008 (UTC)

    • I agree with Greg about the "Notes and references": after checking a couple of browsers at different text sizes, the final product looks better (to me) with that section in a normal font. I've removed the text reference to Notable events of 1795; I've no opinion as to whether it should be linked more discretely or not. As for the internal references, it's quite a delicate task: some can probably go, but I don't think we can reasonably get down to zero. The article tells a story which is more complicated than it appears at first sight, and the "see alsos" are a consequence of this, guiding the reader to section which s/he would never have thought of looking at before arriving at the article. IMHO at least! Physchim62 (talk) 23:06, 2 October 2008 (UTC)
    Yeah, on second thought, the larger font is better for this case. What I had in mind for the See Also links such as the one for the watt balance section is that the links in the prose could link to that section, and there could be a main article template at the top of the Watt balance section pointing to the article. It's not a big deal, though. - Algorerhythms (talk) 23:49, 2 October 2008 (UTC)
  2. Is it factually accurate and verifiable?
    A. References to sources:
    B. Citation of reliable sources where necessary:
    C. No original research:
  3. Is it broad in its coverage?
    A. Major aspects:
    B. Focused:
  4. Is it neutral?
    Fair representation without bias:
  5. Is it stable?
    No edit wars, etc:
  6. Does it contain images to illustrate the topic?
    A. Images are copyright tagged, and non-free images have fair use rationales:
    B. Images are provided where possible and appropriate, with suitable captions:
  7. Overall:
    Pass or Fail:
    Nice article, a few small changes, and it can easily pass.
    Passing after changes made. - Algorerhythms (talk) 22:25, 2 October 2008 (UTC)

Quick link back to Kilogram


The glossary needs references. Further to earlier edits to Artifact, see:
Howarth, Preben (December 2003). Metrology in short (PDF) (2nd ed. ed.). p. 54. ISBN 87-988154-1-2 Check |isbn= value: checksum (help). Artefact An object fashioned by human hand. Examples of artefacts made for taking measurements are a weight and a measuring rod.  Unknown parameter |coauthors= ignored (|author= suggested) (help) LeadSongDog (talk) 02:18, 25 October 2008 (UTC)

  • That definition is too broad and is inaccurate. It would encompass things like watt balance (it is an object), and would rule out objects that were fashioned with the help of machines. Greg L (talk) 03:35, 25 October 2008 (UTC)

    P.S. By the way, thank you for pointing out the 1795 in science article. I didn’t know those types of articles existed. I added a couple of them to the See also section. We don’t want it aliased as [[1795 in science|1795]] since any experience reader of Wikipedia will normally avoid such links. With two of them now in the See also section, that should clue the reader on how to type any other year they might be interested in further researching by just typing it into the search field. These sort of links are quite germane to the subject at hand and beat the hell out of our general trivia articles that Wikipedians have traditionally been linking to. Greg L (talk) 03:49, 25 October 2008 (UTC)

  • Yes, it is broad, but I think not too broad. An artifact is simply a thing which is artificial or literally "made by art". The term also incorporates my left shoe, the 60Hz hum on the phone, your coffee mug, the Sphynx and the International Space Station. "By human hand" is clearly someone's rephrasing of "manmade" for PC reasons. In this context the point is to distinguish an artificial reference from possible natural references such as the geometric ;/) survey reference originally used to establish the metre or the mass of "a cubic decimetre of water". Each watt balance made is an artefact, but of course it is neither a prototype nor a standard. LeadSongDog (talk) 07:00, 25 October 2008 (UTC)
  • There are two famous artifacts that quickly come to mind: the IPK and the old meter stick. There is also a quartz sphere at the NIST which delineates density (but isn’t a defining standard); it is an artifact. There is also the stone “Stack of Charlemagne” that was the basis of France’s old poids de marc system. That too was an artifact. Describing these sort of things as “A simple human-made object used directly as a comparative standard in the measurement of a physical quantity” covers these quite nicely and neatly excludes complex apparatus used as abstracted practical realizations.

    You know, I paused for about 30 seconds when I was contemplating tweaking the Glossary. I actually realized doing so would draw attention to it and elicit just this sort of thing—and probably from you. Please note that there were huge, huge, vitriolic edit wars here over a variety of issues shortly after I landed here. One outcome of all those battles was the removal of the entire section (Mass versus weight) to its own article. One editor who “wouldn’t let go” eventually got blocked for a week because his hair was on fire over my use of a non-SI unit of measure (µGal). And in all that time, not a single editor—not even Mr. Hair-on-fire—raised a single objection to the Glossary being in the article or what was in it. A major concern I had with the very the notion of this article being subject to the above GA review was because this article is quite unique in that it features a glossary. Yet… what was in it—and even its very existence—didn’t even come up during the GA review. The glossary has been extraordinarily stable for a long long time. Now I regret having gone back for a tweak. Can we just walk away from this now? I promise to do the same. Greg L (talk) 17:55, 25 October 2008 (UTC)

I'm not sure why you're invoking edit wars and vitriol you may have had with other editors, but it's not really a reason to stop improving an article, particularly one with "Top" importance. But I'm always willing to discuss changes constructively. GA isn't the end of the road, just a milestone ;/) If the article is to get to FA it will need quality refs for everything in it. The Metrology-in-short ref seems like a good place to start, but I'm not hung up on it. Perhaps you might consider that the definition given conflates the concepts of artifact, prototype and standard. Most artifacts have other purposes that have nothing to do with metrology. LeadSongDog (talk) 21:58, 25 October 2008 (UTC)

Fraction 1000/12

Hey, isn't 1000/12=92.5, not 93.5 as the article keeps saying? —Preceding unsigned comment added by (talk) 14:12, 28 January 2009 (UTC)

  • Huh? It says 100012 (83⅓) moles (which is correct). I can’t find what you are talking about. I find no “92.5” nor “93.5” in the article now, nor were those two values in the version of the article in effect at the time you wrote the above post. I doubt that from where you hail, the University of California, they teach that 100012 = 92.5. Thank you though, for not *correcting* the article, nor adding “The kilogram eats cheese” or some similar contribution. Wikipedia is a resource for all mankind to benefit from. Greg L (talk) 05:50, 30 January 2009 (UTC)

Apparently wrong units

In the watt balance section, there seems to be an error. I've never met the gal before now (I've made the unit name lower case in the article, which is certainly an error correction), but this can't be right:

3.1 µgal/cm (≈3 µg/cm)

Please excuse my inability to express this properly in HTML:

Gals have dimensions of L T^(-2), so:

On the LHS, the dimensions are T^(-2).

On the RHS, the dimensions are M L^(-1).

That's inconsistent, unless someone can explain how dimensions of T^(-2) are equal to dimensions of M L^(-1).

While I have a physics degree, I'm not familiar with gals or the reason for using the unit so I'm loathe to change anything myself.

But it's wrong!

And is there any particular reason why cgs-type units are being used at all? SI has been mks for a long while. For example, elsewhere I see a reference to a quantity expressed in units of g/ml, when it would be better to say kg/l (identical size).

The way it's put is "sub-optimal", but it's not actually incorrect. What that point is trying to imply is that the measured mass of a one kilogram test mass will be different by 3 μg for every one centimetre difference in elevation. However, it has become too abbreviated and so unclear. Incidentally, the gal has the symbol Gal, with a capital letter, as do all symbols of units whose names are derived from proper nouns. Although it's a cgs unit, it approved for use with the SI and is defined in terms of SI units (as, for that matter, is the litre). Physchim62 (talk) 09:00, 19 February 2009 (UTC)

I have to say that any equation is incorrect if the units do not match on each side of the equals sign. In this case, the units do not match: the equation is certainly wrong.

But you've explained what is being described by the incorrect equation, which seems reasonable and useful (hence the continuing use of gals, I suspect) - but also wrong. Can anyone correct it? I've tried to get my head round it, and I can't see a way to do it.

You are also incorrect to state that all units derived from proper nouns begin with capital letters: all SI units have names that begin with lower case letters, although the unit *symbol* might begin with an upper case letter. Gal is not an SI unit, but it's approved for use with SI and is written with a lower case 'g' on the Wikipedia page for 'gal'.

But I've just now read the entirety of the page on that unit, which states: "As with the torr and its symbol, the unit name (gal) and its symbol (Gal) are spelled identically except that the latter is capitalized. The unit should not be confused with the identical all-lowercase abbreviation for gallon, (gal)."

It seems I've gone off half-cocked and introduced an error when I was sure I was surely right. Apologies to all - but the units are still certainly wrong.

Don't worry about having "introduced an error": the point you were making is perfectly valid. As for why we use cgs units here, I assume that's because they're the units used in practice by NIST (who run the Watt balance described here). As the gal is defined exactly and unequivocally in terms of SI units, there's little harm in using it if that's what people are used to. Physchim62 (talk) 10:28, 20 February 2009 (UTC)

The entire Imperial system of measurement is defined exactly and unequivocally in terms of SI units these days, but that's no excuse for continuing to use it.

The US's NIST might well use gals itself, but they are not `all people'. US sources often use units in a fashion that I find very confusing but is clearly what US engineers are used to - see below for a good example. I reckon you're better off doing it the formally correct way so that people who are not familiar with the corruption of correct practice presented here can work out what's going on. No, no, not gals, that's just a minor quibble, there's a link to explain them, I mean that dodgy equation.

Am I being chauvinistic to suggest that I'd rather pay attention to what the UK's NPL uses (also in possession of a Watt balance), because they're more likely to be using metric properly than a US outfit, what with the UK having gone metric pretty thoroughly several decades back (when I was very young indeed). But that's a minor point.

What's still a serious problem is that we've still got a patently incorrect equation in the article. The RHS needs a factor applied to it with - assuming I've not slipped up - these dimensions:

L M^(-1) T^(-2)

for it to have validity - and a numerical value of `1 somethings'. But I can't get my head round it. Can anyone else?

The actual units ought to be something like:

cm/(gs^2) - well, the /g makes sense, because you write that the RHS refers to a `per kilogram' quantity, except we're working in cgs. But you're also talking about per metre (or cm), then - well, erm, the cm (or whatever unit of length dimension is needed) in that factor ought to be underneath, not on top, right?

So I'm horribly confused.

End of deadly serious bit.

(btw, people get used to all sorts of junk. There's plenty of harm in using stuff that people `got used to', because that stuff's often invalid from the strict point of view and therefore wrong and confusing, especially to people who haven't met that particular local form of `what we've got used to'. Or don't you wince when you see references to pressure in, say pounds? (a common error from the USA, to take one example - what's wrong with pascals? Or psi if you insist on sticking in the past - although that one's still allowed if the gauges haven't been replaced since 1955).

Another example: specific impulse of a rocket engine is measured in m/s (assuming modern units). But almost all US sources cite rocket engine specific impulse (so-called) in seconds! Huh? I looked it up: that only works if you introduce a factor of `g' for acceleration due to gravity into the works - acceleration due to gravity at the Earth's surface, and that's supposedly valid in a *rocket* equation? Sorry, that's just plain wrong, and confusing, and gives you a less useful parameter: specific impulse is also the effective exhaust velocity of your rocket engine. The US corruption of specific impulse gives what is to me a meaningless parameter.

I present that purely as an example of why it's almost always a better idea to do things the formally correct way (not to mention in metric), rather than the ad-hoc `what we are used to' way, if only because `what we are used to' is not what everyone is used to, while the formally correct approach is what everyone's supposed to know. It's best for reliable communication, you dig, man?.

Look, people got used to Imperial units, but metric's easier - it seems to be due to confusion over pounds force and pounds mass that US engineers came up with their crazy interpretation of specific impulse. cgs is awkward compared to mks (and anyway units called dyne and erg are silly if you ask me). ARGH! Who the hell uses cgs at all these days anyway? As one engineer taught me: `centimetres are for dress-making, use millimetres or metres'... Sorry, a little rant there, don't mind me. He was right, though - stick with the engineering multiples, it's more convenient. No messing with centi this or deca that.)

  • To I.P. user from Amsterdam: Wikipedia is an encyclopedia, the purpose of which is to educate readers on subjects and properly prepare them for their continuing studies elsewhere. The SI system is a splendid system of measurement. However, not all disciplines use the SI. It does our readers no service to express the world-wide, historical cost of crude oil here on Wikipedia as €219.10/m3 when the world-wide practice in commodities trading is to express it as US$44.12 per barrel. And notwithstanding your distaste of the cgs system of measurement, Wikipedia also follows current literature on Japanese motorcycle engine displacement; it is 750 cc Yamaha engine and not 750 mL Yamaha engine. Nor do we write about a computer with 512 kibibytes (KiB) of RAM notwithstanding the shortcomings and ambiguity inherent in the computer industry’s universal practice of writing 512 kilobytes (KB) of RAM. This principle is upheld at WP:MOS, Which system to use, which says as follows:

* In scientific articles, use the units employed in the current scientific literature on that topic. This will usually be SI, but not always; for example, natural units are often used in relativistic and quantum physics, and Hubble's constant should be quoted in its most common unit of (km/s)/Mpc rather than its SI unit of s−1.

I perceive no need to change MOS on this subject. Furthermore, the Kilogram article is fully compliant with WP:MOS and WP:MOSNUM. As to this particular unit of measure (the gal), in the world of professional metrology and gravimetry, the gal is the unit of measure used. Furthermore, the manufacturer of the highest-sensitivity gravimeters, Micro-g LaCoste, and their FG‑5 absolute gravimeter, measure instrument output in Gal and µGal. That is simply the way things work in that discipline.

I note that you wrote above The actual units ought to be something like… and pushed that theme (how things ought to be) many times in various ways. Notwithstanding the undeniable virtues of the SI, it is not the role of Wikipedia to change the world and promote the adoption of the SI by leading by example, where we show the way to a Better and More Logical Future™®© through our unilateral use of units of measure that are unused in a given discipline; we simply reflect how the world actually works. Again, it is our role to prepare readers for their studies elsewhere and ensure they will be conversant with someone skilled in the art. When it is most common for the professional metrology world to measure gravity gradient in terms of 3.1×10−6 s–2, then Wikipedia will follow that practice.

As Physchim62 properly pointed out, the parenthetical conversion while “sub-optimal”, was correct because it was perfectly clear from the context that the parenthetical was providing the proportional effect on the IPK, which has a mass of one kilogram. As a result of your vigilance, the new wording is even clearer and unambiguous. Thanks. Greg L (talk) 01:06, 2 March 2009 (UTC)

I'm glad you like the change to the text Greg: I was sure you'd spot the discussion sooner or later! Physchim62 (talk) 01:26, 2 March 2009 (UTC)
  • I much appreciate your running with the ball on this one. Thanks especially to you. Greg L (talk) 05:00, 2 March 2009 (UTC)

Traveling at a relativistic speed

A. di M.:

Thanks for this series of edits. It improved the article a great deal by correcting an error. I swear I looked at the actual 1905 paper Einstein wrote and copied its title verbatim, but I must have accidentally looked at his later paper. Good catch.

I’ve tweaked that note to emphasize a critical point. Many people commonly refer to relativistic effects as occurring only when an object is traveling at “close to the speed of light.” Indeed, whereas 10% the speed of light is exceedingly fast and is not—as you put it—an “everyday” speed, it is not “close to the speed of light” by any measure. Nor is it “a significant fraction” of the speed of light (as you also put it). If I coauthored a book and was promised a “significant fraction of the royalties” from my coauthor, I’d be quite displeased when I found I got 10% and he got 90%. What I’m doing is explaining that the proper language to use is “traveling at a relativistic speed” (which is logically and scientifically true while still providing a built-in bit of fudge room depending upon the level of precision at which one performs the experiment) and that it is improper to use the term “traveling at close to the speed of light.” I’ve left your correction of fact untouched but have revised it[7] to better make this distinction without sounding overly argumentative. Greg L (talk) 20:51, 14 March 2009 (UTC)

Well, I guess it depends on what one means by "significant fraction" (if 10% of people in Paris had immigrated from Africa wouldn't you say that a significant fraction of Paris's population is African?) Normally I would just say "at speeds much less than the speed of light", but many readers wouldn't realize that in physics lingo "much less than" usually means "at least tens of times smaller". Maybe "comparable with"? No, even that could be misunderstood to mean "at least half". ... OK, I give up. I wish the emphasis were more on "unless you go *really* fast" than on "but not necessarily very close to c", but I can't think of a wording which would accomplish that right now. --A. di M. (talk) 03:01, 15 March 2009 (UTC)

BTW, a month or two ago, I wrote the director of the BIPM to see if they had a photograph of the IPK (without its bell jars) to release to Wikipedia under a GNU license. The response I got was polite, but could be characterized as “F*** no”. They’d never take such a picture (fainting French physicists) and don’t do that sort of thing with their intellectual property (if I recall the e-mail correctly). The computer-generated illustration is the best closeup we’ve got of the IPK. Australia’s ACPO was a lot more cooperative. They didn’t dig up an old, unused photo; they took the copyrighted one used on their Web site and released it to me under a GNU license. Good Joes. All I did was square the picture up as the original was tilted a few degrees and adjust the color and contrast (compare to original). Greg L (talk) 21:13, 14 March 2009 (UTC)

[struggling hard to keep my fingers from typing more anti-French rant, which I would be unable to write in a polite way at 4 o' clock in the morning] --A. di M. (talk) 03:01, 15 March 2009 (UTC)
  • I’m fine with your counterproposal. Thanks. What you now have still gets the point across that even at small percentages of the speed of light, relativistic effects become significant enough to affect even industrial-grade measurements. Many readers interested in technical matters have read about particle accelerators and how particle speeds are 99.999% (five nines) the speed of light (or six or seven nines the speed of light, etc.) and this leads many people to somehow believe that one has to be pushing on the rubber molding on the speed of light’s bumper before mass, time, and length are significantly affected. In fact, M is affected 5% at on 30.5% c—hardly “close to the speed of light” (it would take over four seconds to get to the moon). Our compromise wording accomplishes that end, and does so with even less of an “argumentative” tone. Very good. Greg L (talk) 18:10, 15 March 2009 (UTC)

Relativity revisited

With all respect to the above contributors, I have to ask myself "Is the kilogram actually defined in relativistic terms?". If you look at the definition of the mole, it has certain relativistic corrections which are metrologically important at the most precise level (eg, the binding energy of the electrons): there are none of these in the definition of the kilogram. The kilogram is currently defined as what the observer observes: hence the popular idea that particles gain mass by moving faster. There is an implicit assumption in the 1889 definition that the observer an the reference mass are stationary with respect to one another: hardly surprising, given that it would be another sixteen years before anyone would suggest that a relative speed might make a difference in an observation of mass. To try an include all this in a discussion of the kilogram fringes on Original Research, but then so does any assumption that relativity should be included in the original definition. Physchim62 (talk) 18:28, 15 March 2009 (UTC)

  • You are correct, Physchim62, the kilogram is not defined in relativistic terms. However, the “kilogram” is not the subject that particular text is addressing. The article, while making the distinction between the (highly) variable nature of weight and the constancy of mass makes this statement: …the mass of matter is constant. Is mass absolutely constant? Well, not exactly; there is a notable and unusually famous exception. Further, that very issue had been raised by other editors here before, so (*sigh*), to properly cover the bases on this all-important anchor unit of the SI system of measurement (and in the Web’s arguably most authoritative article on the kilogram), this 14-word parenthetical qualifier was added: (assuming matter is not traveling at a relativistic speed with respect to an observer). The accompanying note (verbiage that is not part of the main body text) that A. di M. and I tweaked clarifies and expands on the parenthetical qualifier for the benefit of readers who A) don’t know anything about relativistic effects, and/or B) think that one has to be pushing something like “five nines” the speed of light for relativistic effects to become significant enough to be noticeable. Greg L (talk) 22:40, 15 March 2009 (UTC)
    • I can't help but thinking you're mixing apples and pears here. The kilogram is defined in terms of Galilean frames of reference: if you take SR into account, mass is no longer a unique dimension in quantity calculus, and the International System of Units breaks down (unless, of course, you include new defining equations, as is done in practice). Why pretend to explain something which can't be explained? SI is a practical system, it works very well for normal earth-based observations: if you want to do strange observations, you have to take the strangeness of your observations into account when reporting your results. Physchim62 (talk) 22:57, 15 March 2009 (UTC)
  • It would be incomplete and inappropriate to simply state this:

While the weight of matter is entirely dependent upon the strength of gravity, the mass of matter is constant.

The definition of the kilogram (the mass of the IPK = 1 kg) is entirely sufficient and there is no need to introduce the subject of relativistic effects nor compensate for it in the definition; it is totally irrelevant. But if we simply left the above statement like that, it would be (very) scientifically incomplete and not true. You know as well as I do that if we deleted the caveat, some 17-year-old will weigh in with an edit that amounts to “nyuah uhhhh”. Greg L (talk) 23:07, 15 March 2009 (UTC)
  • I agree with you in practical terms, and I don't have a quick and easy solution – if I had one, I'd just edit the article, as you well know! ;) On the other hand, I'm sure that, if you ever learn how to ride rodeo on an electron, you will measure its mass to be constant (by definition, equal to the electron rest mass). Physchim62 (talk) 23:20, 15 March 2009 (UTC)
  • Good. What the parenthetical caveat is doing is agreeing with your point by essentially saying “Yeah, yeah; ignoring relativistic effects so shut the hell up”. The caveat is acknowledging that relativistic effects could theoretically apply but can be ignored in any practical discussion of the definition of the kilogram. Greg L (talk) 23:24, 15 March 2009 (UTC)
  • If I ever have a quiet six weeks or so, I'd love to re-write that whole section… But I'm not going to do it on the quick, because what we have isn't bad, just sub-optimal in one set of eyes (mine). Note that, even in a theoretical discussion of the kilogram, you have to ignore relativity by assuming that it is an independent dimension in quantity calculus. Also, at present, standard masses are compared by comparing weights at constant local gravity: to add that fairly fundamental point about the (current) kilogram complicates matters still further with the technical discussion about the nature of mass. Physchim62 (talk) 23:36, 15 March 2009 (UTC)
  • How’s this? Please revert if unnecessary or revise as you see fit. Greg L (talk) 23:56, 15 March 2009 (UTC)
  • I'm not sure that this is the right place to be discussing this, but then I'm only a chemist; so if I can spot the faults in the discussion, they must be fairly obvious! SR teaches us two things:
  1. that observed mass is not constant, but depends on the relative speed of the reference frames;
  2. that the observed mass of a system is not necessarily equal to the sum the masses of its (non-interacting) parts.
  • GR (in my very basic understanding of it) says the same things, but generalizes them for relatively accelerating reference frames (ie, your lab on the Earth vs. everything else, even if the corrections are usually minute to the point of being negligible). The second of my relativistic corrections is important in determining the relative atomic masses of more than two dozen nuclides (including all those that play an important role in the later part of the article). As I said above, I don't have a quick solution to my complaints, nor do I think that one will appear this evening, but I would at least like to point out that the problems exist (without unduly criticizing the rest of the article)! Physchim62 (talk) 00:22, 16 March 2009 (UTC)
  • Another problem in the same section is defining mass in terms of Newton's second law. That's all very well and good, so long as you have a separate definition of force. On the other hand, if you are talking about the SI unit of mass, the kilogram, it is force which is defined by the Second Law, not mass. A much more minor point is that the current wording makes it seem like Newton measured in SI units, which of course he didn't: if this were the only problem, I'd change it myself, but I would welcome comments on my other complaints before attacking this section with an edit window ;) Physchim62 (talk) 00:31, 16 March 2009 (UTC)


  • Quoting you: Another problem in the same section is defining mass in terms of Newton's second law You have misread what is there. It says:

Per Sir Isaac Newton’s 330-year-old laws of motion and an important formula that sprang from his work, F = ma, an object with a mass, m, of one kilogram will accelerate, a, at one meter per second per second.

That is correctly saying that mass, force, and acceleration are interrelated. That is far from defining mass in terms of Newton’s second law. The kilogram is defined as being the mass of the IPK and the article makes that much clear. As you went on to correctly point out, the magnitude of the newton depends on the magnitude of the IPK; not the other way around. The article makes that too quite clear here at Importance of the kilogram. As for implying that Newton worked with SI units, it doesn’t imply that at all; only that the SI’s units are in accordance with his formulas.
As for relativity, I find your points on this to be a bit too esoteric. The text is clear that, unlike weight, mass is constant (unless one wants to get nitpicky with relativity), and that relativistic effects have zero influence on the magnitude of the IPK. It says or implies nothing more.
Oceans of people have been reading that text for a long time now, and it just doesn’t seem to be eliciting the sort of confused responses one would expect from reading your objections. A. di M., who specializes in this sort of stuff, and I have arrived at compromise wording that makes us both happy. Perhaps you are overanalyzing it. If you still disagree, perhaps A. di M. will step in here. Greg L (talk) 03:21, 16 March 2009 (UTC)
Mhh. First, let's make terminology clear here. In SR, the term mass can refer to two things: the rest mass and the relativistic mass. The former is a property of a body which, by definition, doesn't depend on the observer; the latter is essentially the total energy of the body (divided by the square of speed of light), and does depend on the observer. As the footnote says, M = γm0 where γ is the Lorentz factor. (In fancier terms, the relativistic mass is the zeroth component of the body's four-momentum, and the rest mass is its norm—modulo signs and factors of c, which depend on which metric convention one decided to use when he got up this morning.) This is as with three-vectors, where the length of a vector doesn't depend on your choice of axes, but its third component depends on which axis you call z. The total relativistic mass of a system equals the sum of the relativistic masses of its parts, but its total rest mass can be more of the sum of the rest masses of its parts. (This is as with three-vectors, where the third component of a + b equals the sum of the third components of a and b, but its length can be less than the sum of their lengths.)
What does the unqualified term mass refers to? To the relativistic mass or to the rest mass? Well, it depends on whom you ask (see [8]). In the past the former meaning was more common, but more and more people are starting using the latter one. I think that on Wikipedia we should never use the unqualified term mass unless it is either obvious or irrelevant which meaning we are using, and we should say rest mass or relativistic mass in all other cases.
Is the kilogram a unit of rest mass or of relativistic mass? Well, AFAIK the BIPM has never decided (whereas it has decided that the second is a unit of proper time and that the metre is a unit of proper distance). So I guess it can be used for both, and the article should simply say that it is a unit of mass, as it currently does. In an ideal world the article about the kilogram would not even mention the distinction, but, as Greg said, You know as well as I do that if we deleted the caveat, some 17-year-old will weigh in with an edit that amounts to “nyuah uhhhh”. The bottom line is that I think that the current version of that sentence and of its footnote is just fine; I'm just not 100% sure that the second sentence of the footnote is needed (and what is "interesting" to someone, can be something about which someone else doesn't give a damn). Also, I don't think that the sentence about F = ma sounds like a definition; I'm just replacing "per" with "according to" per some part of the MoS which recommends using "for example" and "that is" rather than "e.g." and "i.e." and which I can't find right now, but it is otherwise fine. --A. di M. (talk) 15:57, 20 March 2009 (UTC)

Better Photographs of a Kilogram Standard

Better Photographs of the Actual Platinum ingot exist. I motion we add these to eitehr complement or replace the computer generated version on the main page.

I like the clarity, of both the subject and the photo quality, of the first image from the NIST MEL. However, its use within the Kilogram article may not be possible, since free use of the image is restricted to only materials which directly address NIST programs directly. I think it would be best to keep the render, add an image of the ingot itself, and also add an image of the ingot behind glass. This would give the reader more than enough information upon first glance to determine the scale of the ingot. It would also suggest the importance of the ingot, which to the uninformed, may not be readily apparent. In any case, an actual photo of the ingot is ideal. (talk) 11:47, 24 June 2010 (UTC)

Location of SI multiples section

I only have one major reason to put the SI multiples section at the end of the article; it isn't readable. It's not part of the narrative of the article. It's a section people should go to for reference, not something to read in a narrative flow. Essentially, I think having the section near the top of the article will prevent most readers from actually reading the article. They'll get to that section and figure that if the article already has devolved to the point of being an informational table with notes that it isn't worth reading any more.

On the formatting; if images are large, there will not be enough text to fill the spaces between them, no matter how long the text is. So, following the recommendation in the manual of style, I've removed the pixel specification on all of the images except the lead image and the graph (which would be unreadable in a smaller size). If readers want to see the full glory of the image, they can allows follow the link. There are some seriously wonky formatting problems with images sometimes, but having the next section start before the image from the previous section has ended is, not, to me, a serious formatting issue. I've reduced the size of the caption (you know, made it short and sweet, like I do). It takes a fairly wide window to get the formatting "problem" now, but I don't really think it's a problem. The SI multiples section has a short bit of text and then the centered table, so the image from the previous section is actually making the formatting more pleasing to me. I also don't think there is anything wrong with six paragraphs without images.

Because GregL invited me to change the article back again if I had a strong reason, and I wanted to show my suggested formatting changes, I've done the edit. Don't worry, I'll keep this article watched until this spate of collaboration settles down. - Enuja (talk) 20:14, 9 March 2008 (UTC)

A precise and controlled 5:1 reduction in size (264 pixels wide) in a high-contrast image like this results in a very attractive, tack-sharp image.
180, 200, 250, or 300-pixel widths (depending on user preference settings), make high contrast images with fine details look fuzzy. Here, a 250-pixel user preference is illustrated. It is close to the 264-pixel width but isn’t an exact integer divisor (±1 pixel) of the original image’s 1319-pixel file size.It appears that Wikipedia's picture-rendering engine has much improved. They are equally as sharp now. Greg L (talk) 06:55, 3 March 2010 (UTC)
* That’s fine Enuja. Rational reasons implemented to good effect. I revised (and necessarily slightly expanded) the caption. The photo of the Meissner effect would amount to little more than pretty decoration if the caption doesn't truly enhance the reader’s understanding of the experiment. Since you’ve been working on the Kilogram article for a long time and you didn’t understand the nature of the actual experiment, then there were undoubtedly many other readers getting it wrong too. Greg L (my talk) 22:25, 9 March 2008 (UTC)

P.S. One of the Japanese experimenters’ big problems was magnetic hystereis due to flux trapping at the edges of the material and asymetrical forces. They also had problems keeping track of sideways or tilting motions. Even the helium gas adhering to the mass at the low temperatures was a significant correction. There are some others now trying to do levitation a bit differently. Unfortunately, I haven’t received any information or published papers on these newer experiments. Greg L (my talk) 22:35, 9 March 2008 (UTC)

P.P.S. As you can see, I left all your changes to picture size alone except for one, for reasons illustrated above. Besides, this particular image is mostly decorative and there’s plenty of room in that section for it—regardless of window width. The picture is supposed to have an effect at an intuitive, almost emotional level: electricity and light beams being affected by a hunk of metal. It's better when the picture really pops. Greg L (my talk) 23:00, 9 March 2008 (UTC)

reversion of changes which are principally stylistic

See Wikipedia:Arbitration/Requests/Enforcement#Greg_L. My position is that there's no reason to change the ref-margin for this article only. — CharlotteWebb 12:29, 3 July 2009 (UTC)

CharlotteWebb, I thought your complaint there was a petty way to get your way. You waded deep into the history of this article and dug up an edit from March of 2008 to get your way (well before the restriction was placed on me). Note that you were properly advised at your complaint to be more careful next time. Please be aware that CSS is supported by Wikipedia’s rendering engine for a reason: the developers want it that way and editors are free to use CSS to improve Wikipedia. Your little stunt shows that hard work here on Wikipedia will not go unpunished. BTW, I’m appealing ArbCom to resolve that particular restriction, which I feel is unwarranted. Greg L (talk) 21:26, 3 July 2009 (UTC)
The use of embedded markup to nudge the margins on stuff in this article is inappropriate; MediaWIki:Common.css is the place for such stylistic details to be implemented — as has been suggested in several of the threads about teh wiki. Last I looked (a few days ago), there was much other low-level markup in that page and I expect that on closer examination I would support removing good deal of in in favour of canonical forms. Cheers, Jack Merridew 09:30, 9 July 2009 (UTC)

Section compatibility?

I don't see any talk on compatibility of different sections. Can any of the parts of one section be used in another? For example, can An be made to use the 844468863 but at the same time use, say, the Watt balance method for finding the mass of the Kg?

Reddwarf2956 (talk) 18:46, 18 August 2009 (UTC)

The nature of mass

Why is there a paragraph entitled "The nature of mass"? Do we not have a separate article for mass? This paragraph is completely unnecessary and it doesn't say anything that people shouldn't already know anyway. Whoever wrote it shouldn't be filling the article with unrelated trivia. Can someone get rid of it please? I'd do it myself, but I don't think I'd be able to do it right; I don't know how to deal with the table of contents etc.(Huey45 (talk) 12:59, 5 November 2009 (UTC))

The distinction between mass and weight are nuances that are not widely appreciated. It is a fallacy to think that such a topic need not be covered encyclopedically in an article about the very definition of the SI unit of mass. Asserting that the section “doesn't say anything that people shouldn't already know anyway” pretty much undercuts the very basis for encyclopedias even existing. Yes, there is a separate article covering the distinction between mass and weight; that’s why articles often have abbreviated overviews of the subject and have a {main} tag directing readers to the full topic. Greg L (talk) 05:25, 23 November 2009 (UTC)

With the advent of space technology shouldn't Newton's constant of acceleration rate to the earth be decreasing. I mean with all the manmade space debris the total mass of the earth has decreased slightly. Hence a lower gravitational force upon objects on the earth. So on a molecular level we are substantially lighter today then say 50 years ago. Wouldn't that upset the natural rate of metabolism occurring which is dependent on the 9.8 N rate of accelleration to occur on the planet names Earth by the human race solely? Wouldn't that create a potential difference hazardous to the present state of life. Carl Kravis —Preceding unsigned comment added by (talk) 11:11, 25 November 2009 (UTC)

Meteorites add to the mass of the earth about 150 000 tonnes per year,[9] much more than we send into space. And even that has a negligible effect on the total mass of the earth. --agr (talk) 17:20, 26 November 2009 (UTC)

The U.S. owns K79 as well. And gave K650 back...

Footnote 10 claims that the U.S. has four Pt-Ir mass standards:

  • K20, the official mass standard
  • K4, a check mass
  • K85, "used for Watt balance experiments", and
  • K650, an underweight prototype

However, The Kilogram and Measurements of Mass and Force (2001) states that the U.S. has K4, K20, and K79; it makes no mention of K85. Recalibration of the U.S. National Prototype Kilogram (1985) states that K650 was only a loan and "The artifact was returned to BIPM in October 1984." (end of section 4.2, p. 267).

(The latter also mentions that the U.S. has had a pure Pt kilogram, the "Arago kilogram" (KA) since 1821.)

Can someone find a citation for the U.S. possession of K85 and K650? I once remember finding on the web a full list of national prototype assignments, but I can't seem to find it any more... (talk) 11:01, 26 November 2009 (UTC)

P.S. Found a citation for allocation of No. 85 to NIST for Watt Balance experiments...

  • I’ll take your word for it. You have clearly read the papers and done your homework. I had mentioned about K650 because that is what the NIST researcher mentioned he used in one of his e-mails to me. I *assumed* he still had it. If it was returned, then what I had there was incorrect. Thanks. Good work. Greg L (talk) 00:37, 6 December 2009 (UTC)

Bold edits

Kbrose, I think your series of edits was a bit too bold. Your edit summary had items like “copyedit, term 'stability' is ambigous”. Note that such basic terminology is not only perfectly scientifically accurate for any unit of measure in the physical sciences, “stability” is the term used by all the metrology world’s papers to describe the issue with the kilogram. The job of any good encyclopedia is to educate readers on the basics of a subject and properly prepare them for their studies elsewhere. Let’s try to to dumb this down too far, shall we?

As for slapping {cite} tags all over it, the article is going to be far too footnoted if every single assertion in the entire article has to make reference to the same set of cited papers. Citation 8, 10 (the central Girard paper), 11, 12, and (especially) 18 are the notable citations this article uses. It would be nice if you actually read these papers (which you clearly did not) and then go to this article and do a more selective job of deciding what really requires yet another citation. Usually, one citation to a given paper per section of the article ought to suffice.

I note, for instance that this article originally had a hidden editors note for curious editors who might like to know the basis for the statement that “none of the replicas equals exactly one kilogram.” That hidden note stated “<!-- the closest is Hungary’s K16 at 1 kg +12 µg (Girard) -->”. I see that you chose to bring that verbiage out into the article as visible text and then slapped a {cite} tag on it!?! Baffling. First of all, note the parenthetical (Girard) in that hidden editors’ note. What in the world did you think “Girard” means? Are you not even reading the citations that are already all over the article? Moreover, that edit seemed wholly unnecessary on a number of fronts. The effect was to add text to an article and then question your own text (after you stripped out and ignored the accompanying citation to Girard). I’m sorry, perhaps you have your reasons for editing the way you do, but in a collaborative writing environment, such a style smacks of editing laziness. If you add text to an article, I suggest you do your own citations and not leave it to others to do all the “dirty little detail work” for you. Even after you un-hid the text (and stripped out the obvious citation), it would still have been clear enough that such an assertion is buttressed by Girard’s paper detailing the results of the third periodic verification, which started the whole metrology world’s concern over the kilogram and is the central paper on which the whole “stability” section is based. Typically, common sense suffices in technical writing.

Note also, Kbrose, that articles like Kilogram don’t obtain GA status by having gapping flaws in their lead sections of all things. GA status certainly doesn’t mean that articles are in any way perfect and can’t be improved, but they do mean that Wikipedia’s best experts on proper, Wikipedian-style and form and proper technical writing techniques have gone through the article and that a number of editors were quite happy with it. So, once again, your slapping an {intro-tooshort} tag on the article (so it has a little “dust broom” icon at the top) seems far too bold as it is clearly entirely contrary to the consensus view. One of the attributes for which Wikipedia is famous is its pithy, clear leads; it has served Wikipedia well. Greg L (talk) 21:22, 11 December 2009 (UTC)

Fruit juice picture

I have reinstated the fruit-juice picture - many articles that discuss SI units of measure have examples of the unit in of measure in question. Rather than create a new section Visualising the kilogram, I felt that the picture was sufficient. Do other editors feel that a new section should be added to the article, that the picture should be ledft where it is, that it should be moved elsewhere in the article, that an alternative picture should be included (iff so, please supply the picture) or that it should be deleted? Martinvl (talk) 06:22, 1 March 2010 (UTC)

The containers are in no way familiar to me. The only thing in the picture that helps is the 1L marking on the containers. There is no sense of scale in the photo - nothing to compare the size of the containers to. --JimWae (talk) 08:20, 1 March 2010 (UTC)
In my opinion this picture should simply be removed, and I nearly did it myself before Greg L did. We already have two pictures visualising the unit: one in the infobox and another under "Stability". Perhaps we should say more clearly that for all household intents and purposes a litre of any beverage is exactly a kilogramme. And I would agree with illustrating the fact with fruit juice. But definitely not with a marketing photo that shows a representative choice of products of a single brand. The need for such a photo isn't sufficiently high to warrant such a problem. A photo of several brick-shaped (not gable-top) tetrapaks/combiblocs of milk and juice of several brands might be more acceptable. Hans Adler 08:33, 1 March 2010 (UTC)
The "1 litre" text is the important part of the picture - the brand might be obscure - the text "1 litre" is not. By all means replace this picture with one that is more readily understood by readers on both sides of the Atlantic, but until you do this, please leave it where it is - it is not better than nothing.
Regarding other comments, the picture in the infobox should in my view be modified to show a metric ruler (or at very least one with both metric and imperial scales). Also, since it duplicates the picture of the IPK, only one of the pictures is neccessary - neither picture actually conveys to the reader a readily-understandable visualisation of a kilogram.
Martinvl (talk) 08:51, 1 March 2010 (UTC)
I am not sure that you got the gist of my comment:
The picture is spammy, and it isn't necessary. If and when a more acceptable picture is found or created, that picture can be added. (I will keep my eyes open. Perhaps a photo taken in a shop will do.) But this picture needs to go. This is not an article about the wide range of excellent fruit juices sold under the Tymbark brand. Hans Adler 09:05, 1 March 2010 (UTC)
I am more than happy for this picture to be replaced by something more suitable. I agree that it is verging on spam, but it was the best that I could find in Wikipedia Common. I look forward to it being replaced by a better picture - meanwhile it does perform a role in reminding readers that a litre of juice has a mass of approximately a kilogram - moreover many readers are familiar with the concept of a litre of juice, but very few have had the privillege of visiting the BIPM laboratories in Sevres and even fewer of actaully lifting the IPK. Martinvl (talk) 10:21, 1 March 2010 (UTC)
For the record: the subject of this discussion. A pretty advertisement of colorful Tymbark fruit juice packages that does nothing whatsoever to convey a sense of proportional scale or the volume of a liter.
  • There is clearly no consensus here for keeping the picture. For the reasons stated in my edit summary when I removed it the first time, as well as for the reasons stated above by others, the article is far better off without it. The second sentence of the lead explains that a kilogram is close to the weight of a liter of water. Your argument that the photo illustrates the liter is spurious since at the resolution in the placed image, one can't even discern that the package is marked as containing “1L” nor is there anything else in the image to provide a sense of scale. As such, the picture doesn’t illustrate “liter”; it merely illustrates “colorful juice package” and adds no value whatsoever to the article.

    I see no reason in the world for A: an advertisement for Tymbark juices to remind people of what juice cartons look like, and B: such a needless picture shoe-horned into the history section (inane); or C: a create a whole new section dedicated to the proposition that a general-interest readership needs to be shown what pretty, one-liter Tymbark juice cartons look like.

    In a nutshell, the picture and its caption is not only unencyclopedic, but add no value whatsoever; most everyone who hasn’t crawled out from under a rock on this pale blue dot knows what a liter is. If you have a special audience, such as third-grade children to whom you want to expose a fundamental concept like the volume of a liter, there are a wide variety of more suitable sites on the Web.

    I supposed you could stage a special photograph showing a plain white bottle or carton marked clearly with “One Liter” and have it being held by an average size human for scale (crucial to convey a sense of scale and volume). But then, we come back to the fact that creating a whole new section in this article (or placing it in an existing section where it clearly is out of place) to illustrate the drop-dead obvious isn’t desirable since this article isn’t directed to third-graders. Greg L (talk) 19:28, 1 March 2010 (UTC)

  • P.S. Since, the second sentence in the lead states “…which is almost exactly equal to the mass of one liter of water”, and since “liter” is linked, clearly a much better place to illustrate the volume of a liter is over in the liter article; it currently doesn’t have any pictures or illustrations to convey a sense of the volume of a liter. There will clearly be push-back from the community over there against your current picture since it fails to convey one iota of the information you purport it conveys. If you can find a more suitable picture to convey a clear sense of the volume of a liter (relative scale to common, well-recognized objects is crucial), you could greatly improve that article, which is about a unit measure of volume. This article is about a unit measure of mass. Readers can follow the link to our liter article if they are galactically clueless about its volume. Greg L (talk) 19:40, 1 March 2010 (UTC)
I had the same negative reaction when I saw the fruit juice photo: it looked like an advertisement. I almost reverted it immediately but I decided to sit back and see how other people reacted first. I'm not opposed to a quick visual aid that shows the tie between a liter of water and a kilogram mass, but this photo cheapens the article in an aesthetic way without adequately conveying the idea. I could live without any photo at all like this, but if there is going to be one, it should be something like a chemistry flask of plain old water measuring an obvious 1 L. A ruler or other common object showing its scale wouldn't be a bad idea also. CosineKitty (talk) 19:55, 1 March 2010 (UTC)

Seriously, how ignorant do you think people are? I'm pretty sure everyone has a pretty good idea of how big a litre is without having to look at an advertisement for fruit juice. As someone already mentioned, there's no indication in the photo that those bottles are each 1L anyway. (Huey45 (talk) 11:29, 2 March 2010 (UTC))

Huey, I’m pleased you agree that we don’t need that fruit-juice image here. However, universal, galactic “ignorance” of the subject matter is not a prerequisite for illustrations to be added to encyclopedias. Our Dog article has a photo of a dog in the article’s lead. Photos (properly selected ones that speak to the subject matter) enhance our articles and make them look more professional. I would argue that 99.9999% of English-speaking adults who hop onto the Internet and come to Wikipedia know what a dog is; yet, there’s that picture in our Dog article. Notwithstanding the ubiquitous two-liter pop bottles at grocery stores, the fact that America hasn’t yet gone metric and non-technical people seldom measure out fluid volume in milliliters and liters, an illustration to convey a sense of the volume of a liter on Wikipedia is a good idea. What Martinv did was use a poor picture in the wrong place. Greg L (talk) 18:41, 2 March 2010 (UTC)
Actually it may depend on the region. JimWae claims not to know this type of container, so perhaps he is not even used to the more traditional Tetra Pak bricks, or to anything sold by the litre? I don't know how it is in the US, but it seems possible to me. Metrication in the United States says the most common metric container is the 2-litre bottle, which seems rather odd to me. But if people don't know how much a litre is, then it will be because they are not used to 1-litre containers, and then a picture of a 1-litre container is not going to help. Hans Adler 13:28, 2 March 2010 (UTC)
More like it, but still no hand for scale
  • As I mentioned in my postscript, above, there is probably a legitimate, encyclopedic need to illustrate the volume of the liter here on Wikipedia—but in our Liter article—not here on Kilogram. Wikipedia would start looking like a grocery store advertisement in the newspaper (or an explosion at the Disney animation studio) if every single time one of our articles mentioned that something was “equal to one liter,” it got slapped with a fruit-juicy picture of the wide assortment of Polish Tymbark juice drinks for benefit of American hillbillies who think a liter is what their hunting dog sometimes gives birth to.

    I think an illustration is needed somewhere; something along the lines of what CosineKitty suggested (a chemistry flask) would suffice. But, again, it belongs in our Liter article. Splitting hairs here: flasks are highly tapered so their total height doesn’t contribute much to their volume and that, IMO, makes them less than ideal. A one-liter chemistry beaker (illustrated) held in what is clearly an adult’s hand would be better. A hand or some other, well recognized, standard-sized object must be in the picture, otherwise there will be no sense of scale and we subvert the entire purpose of adding the picture: conveying a sense of volume for the benefit of someone who is unfamiliar with the liter. Greg L (talk) 18:28, 2 March 2010 (UTC)


It is not common practice for Wikipedia articles to include "glossaries" of perfectly common terms. This is what wiktionary has been designed for. As a reader, I feel treated as a moron if an article text is graced with wikilinks that do not take me to dedicated articles but instead to a "glossary". No doubt the intention is most well-meaning. I see there is even a html comment, "this glossary is a necessary thing for this particular article. It is a unique circumstance and the remedy, a unique color for links to this section, makes reading this article a better experience"

I do not understand why this particular article should be considered in particular need of a glossary, or how anything discussed in this article qualifies as "unique circumstance". I recommend just doing away with the glossary as misguided. --dab (𒁳) 16:47, 17 January 2010 (UTC)

  • Wiktionary isn't up to the task in this particular case. Note how the various definitions frequently refer to each other. It would be a thoroughly tedious for readers to keep all these relationships straight while bouncing around from place to place within Wiktionary. Note too that this article achieved GA status with the glossary in place. That, of course, doesn't mean the article can't be improved. What it does mean is that many experienced editors pored over the article and recognized the need for a glossary in this instance and also recognized how cumbersome and impractical it would be for the information to be dispersed throughout Wiktionary. Glossaries in certain publications exist for a reason (notwithstanding the existence of dictionaries): convenience for the reader. Greg L (talk) 00:01, 29 January 2010 (UTC)

None of those definitions are particularly arcane. I don't see the need for this glossary. Some of these terms like 'IPK' are already defined inline in the body of the article. The majority are obvious to any English speaker and rather insulting to one's intelligence. A number are incorrect definitions to clarify poorly written text in the article itself are also included. If it's not clear from the context that 'prototype', 'sister copy', or 'replica' are referring to the IPK, that's an error in the article's body and needs to be fixed. These terms are not defined in relation to the IPK and a glossary is where you define domain-specific terms, not clarify poor writing. Even completely non-technical people I know have no trouble reading this article. (talk) 23:07, 27 June 2010 (UTC)

I'm a bit confused as to whether this article is in American or British English. Is the confusion regarding the correct spelling of "litre" (in British English) a result of an over enthusiastic bot or the all-pervading spell chucker? Or is the article lifted direct from the US Wikipedia in some way? Drg40 (talk) 08:07, 10 September 2010 (UTC)

I'm equally confused about the American/British spellings. Particularly as both "litre" and "metre" are spelt in the international/standard/French manner in their own articles. Can we have the decision to use "liter" and "meter" revised? Dayveday (talk) 02:41, 8 November 2010 (UTC)

Automate archiving?

Does anyone object to me setting up automatic archiving for this page using MiszaBot? Unless otherwise agreed, I would set it to archive threads that have been inactive for 30 days and keep ten threads.--Oneiros (talk) 21:20, 22 March 2010 (UTC)

 Done--Oneiros (talk) 22:36, 28 March 2010 (UTC)
  • Fine. Thanks. Greg L (talk) 21:35, 6 May 2010 (UTC)


The Kilogram#Importance of the kilogram section appears to contain some questionably neutral statements, but I'm not sure. "The long-term solution to this problem, however, is to liberate the SI system’s dependency on the IPK by developing a practical realization of the kilogram that can be reproduced in different laboratories by following a written specification." in particular strikes me as advocating a point of view. It seems like original research to me, anyone disagree? Falcon8765 (TALK) 20:36, 3 October 2010 (UTC)

I don't see it so much as advocacy as a statement describing an activity, that the metrology community has been working on for several years, to eliminate the need for physical prototypes and for transfer standards. It has been long established for distance and for time, but mass has been more challenging. LeadSongDog come howl! 20:53, 3 October 2010 (UTC)
The statement represents the overwhelming consensus in metrology circles. There's less consensus about what the written specification should be or when the change should happen (and the article reflects this), but very few people suggest that scrapping the IPK would not be a Good Thing at some point fairly soon. Physchim62 (talk) 20:59, 3 October 2010 (UTC)
I have no particular opinion about the IPK, but was read the article and the section just popped out at me. Could we get a source or two demonstrating that it is the scientific consensus? And perhaps a minor rewording that indicates it is such? 20:24, 4 October 2010 (UTC)
Citations to further buttress that the metrology world wants to liberate the SI system of its dependency on the last artifact? I second what Physchim62 wrote. Besides, if all the work being done on alternative definitions doesn’t drive home that fact, the CIPM’s latest resolution fully well does. Greg L (talk) 01:19, 7 November 2010 (UTC)

Does anyone want to start work on making this a featured article?

I'm a big fan of Wikipedia but haven't contributed a whole hell of a lot, so maybe this is an inappropriate request, but would some of you big contributors (to this article or elsewhere) be willing to consider taking on the task of making this article a featured article? I just stumbled across it and really expected a gold star, especially since this is such a fundamental topic to science and is so well written, but I was surprised. Just a suggestion. Bantam1983 (talk) 06:16, 22 October 2010 (UTC)

I might help a bit, but I am not particularly motivated because I don't consider articles on individual units particularly thrilling. The metric units are perhaps a bit better than the others in that their rich history is recent enough to be very well known. A counter-proposal: It might be worthwhile to bring the other metric units also to good article standard and get the entire set through the good topic process. After that there will probably be enough momentum to get a few featured articles and perhaps make the entire thing a featured topic. Hans Adler 07:07, 22 October 2010 (UTC)
I was the main shepherding author who grew this article from its humble beginnings (history). I once had one of my wiki-friends nominate it for FA. That wasn’t too long after it had gone through the Good Article process, which wasn’t too bad of an experience. But I had seen what the FA process was like (not fun) and pledged that I wouldn’t lift a finger to help the article through the process. That was the end of that. Was that the right thing to do? Well, I come to Wikipedia because it is a fun hobby. If something isn’t fun, I avoid it. Just that simple.

And why avoid FA? I’ve done a few things on this article that aren’t seen in many other articles (maybe any other articles), such as the Glossary, which is desperately needed since many of the terms have a unique meaning in the metrology world and they also refer back and forth to each other; keeping all that straight by bouncing about in Wiktionary would drive someone mad. I find that Wikipedia has a lot of people who value conformity—even to the point of not best serving the interests of our readership. Frankly, the thought of having some wikipedian *experts* ride in on a mighty stallion with pouted lower lip as they wipe their white gloves over the article’s crevices sounds like about as much fun as being stuck on a deserted island with nothing but a knife and Jessica Alba (at least one could eat Rosie D’Donnel).{PC disclaimer}

The FA experience is perfectly natural because people have egos and a volunteer wikipedian who has been anointed with *expert-hood* status by his or her social network desires to validate their social status by demonstrating that they can improve most-any article presented to them. Why would anyone not want to help an article achieve gold-star status by improving it in some way? But, just because something is perfectly natural (biological excretions are natural too), doesn’t mean it is 100-percent goodliness top to bottom.

Besides, when an article achieves FA and gets its little gold star from Teacher, it necessarily appears on the Main Page for a day and that would just result in a week of drive-by shootings by 9th-graders and dorks (more non-fun).

But with regard to your comment: I just stumbled across it and really expected a gold star, especially since this is such a fundamental topic to science and is so well written, but I was surprised, Bantam1983, I’m very pleased to hear of your reaction. While greatly expanding this article, I exchanged well over 60 e-mails with the Ph.D. physicist at the NIST who is working on the watt balance. He e-mailed me that picture of the watt balance. Since I have extensive experience designing PEM fuel cells, which use platinum catalyst, he even passed along an observation of mine to the BIPM about one of the solvents they use to clean the IPK and how that might well be responsible for the short-term (30 day) instability it exhibits after cleaning. I’ve certainly given this article my best effort and enjoy hearing from people who appreciate it; you made my day. Who needs FA with comments like yours? Greg L (talk) 01:14, 7 November 2010 (UTC)

Formula layout

I'm not sure about other browsers, but in ye olde IE7 the present layout of the fixed-h based definition does not render at all well, with the lines running together to the point of illegibility. It might be worth exploring other layout options. LeadSongDog come howl! 18:30, 10 November 2010 (UTC)

  • Still other editors complain that thinspaces don’t render at all well. Let me be sure we are talking the same thing. Are you saying this…
1 kg = c2/h = f
…isn’t looking right for you? How about for Firefox? I do understand that IE7 is awfully ubiquitous and the issue you are seeing should be addressed if it is endemic to IE7. Could you please confirm that other computers (those of your friends) using IE7 render the same way? If so, we should certainly find a better way. Greg L (talk) 18:43, 10 November 2010 (UTC)
P.S. If the problem is appearing on other computers running IE7, please copy every instance of a formula that isn’t rendering well for you to this talk thread. Greg L (talk) 19:17, 10 November 2010 (UTC)

(edit conflict)

No that line seems fine, the problem was with blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah ( 299,792,45826.62606896×10−34 ) hertz.”  yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda, where the denominator runs into the following yaddas.
It appears that the following lines of text are equispaced below the 299,792,458, rather than below the lowest descender. Perhaps some kind of stylesheet error?
On the other hand, blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah ( 299,792,45826.62606896×10−34 ) hertz.”

yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda does not run together, but suffers from discontinuous text after the quote.
I'll check later to see what IE8 and Safari do. I've only got access to one IE7 machine at work.LeadSongDog come howl! 19:37, 10 November 2010 (UTC)
Oh. That expression {{nowrap|1=( {{frac|299,792,458<sup>2</sup>|{{val|6.62606896|e=-34}}}} ) [[hertz]].}} uses the {val} template within the {frac} template. That results in a superscript within a superscript, and produces a superscript within a subscript. In other words, the browser has to be able to support double-levels of super- and sub-scripting, i.e., ( 299,792,45826.62606896×10−34 ) hertz. Those fractions have been here for a while (years) and I’ve looked at them on piles of computers in different places on everything from Barbarian-OS to OS X and every browser imaginable. I never saw them incorrectly rendered. I hope something new hasn’t cropped up in IE7. It just may be that the IT dudes at your company have things shortchanged there. Let me know. Greg L (talk) 20:15, 10 November 2010 (UTC)
Perhaps. When I view the rendered page html, I see <dd>No that line seems fine, the problem was with blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah <span style="white-space:nowrap;">( <span class="frac"><sup>299,792,458<sup>2</sup></sup>⁄<sub><span style="white-space:nowrap">6.626<span style="margin-left:.25em">0</span>68<span style="margin-left:.25em">9</span>6<span style="white-space:nowrap;margin-left:.15em;margin-right:.15em">×</span>10<sup>−34</sup></span></sub></span> ) <a href="/wiki/Hertz" title="Hertz">hertz</a>.”</span>  yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda, where the denominator runs into the following yaddas.</dd> <dd>It appears that the following lines of text are equispaced below the <i>299,792,458</i>, rather than below the lowest descender. Perhaps some kind of stylesheet error?</dd> if that helps at all... LeadSongDog come howl! 20:52, 10 November 2010 (UTC)
As Nixon (I think) once said: Let me say this about that. I’ve got a Mac that can launch into Bootcamp so it can run Barbarian OS (XP-Pro). There, I looked at the {val}/{val}-within-{frac} construction using both IE8 and Safari. In Safari on Windows, the fraction looks gorgeous. In IE8 (again, on XP-Pro running under Bootcamp on my Mac), the superscripts within the fraction are readable but very small. Surprisingly, selecting a larger font didn’t make those doubly-superscripted numerals any larger. My brother sent me screen shots from his Genuine Windows®™©(yuck) machine when running IE8 and Firefox. HIs IE8 results looked identical to mine: very small, but still readable. The fraction looked perfectly fine in Firefox on his XP setup. And, of course, the fraction looks gorgeous in Safari running Mac OS X (as it does in Safari under XP-Pro). I also spoke with my programmer friend. He has a triple-boot Mac laptop that can boot into either OS X, Windows XP, or Linux. With Ubuntu on Linux and using the Opera browser, the fraction looked fine and perfectly readable to him. My friend uses Opera because a version is available for each of the three OSs he uses. According to him, Opera is rather weak with its rendering engine so if something appears fine in Opera, it will appear fine in most any other browser. If the fraction is just flat broken for your IE7 system at work, I think it is something unique to that machine. If you can, try Safai; it’s really fast and produces gorgeous text. Greg L (talk) 00:29, 11 November 2010 (UTC)
Sorry, no option on what browser I use at work, its all locked down. At home, IE8 on Vista renders it just fine (with the same html). Safari on my iPod Touch also does a nice job of it. I didn't think to check it without logging into WP at work, I'll try that Friday. Thanks for the feedback.LeadSongDog come howl! 03:17, 11 November 2010 (UTC)
You are most welcome, LeadSongDog. Yes, let me know if your user settings (as evidenced by not logging into Wikipedia) resolve it for you; that would be interesting. Greg L (talk) 16:09, 11 November 2010 (UTC)
Not the user prefs, it's the same without logging in. In any case, the effect is font-scaling dependent. With IE7 View/Text-size/Medium (or larger) the lowest part of the denominator runs into the next line. At reasonable modern screen resolutions, however, View/Text-size/Small (or Smallest) is illegible. Mine is at 1280x1024. Any idea where the font size and spacing would be found for this? I'm using the default vector skin. In Largest, it renders with full overlap of the next row!LeadSongDog come howl! 19:24, 12 November 2010 (UTC)
trying a tweak, blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah 2997924582×1(6.62606896×10−34)hertz.” yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda does not run together until Largest, and scales well.
Alternatively, blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah 2997924582/(6.62606896×10−34)  hertz.” yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda yadda avoids the problem entirely. Perhaps less elegant, but legible. LeadSongDog come howl! 20:15, 12 November 2010 (UTC)
I only use XP Pro for some special medical software to analyze gastric data from those little pills patients swallow that transmit pH, temperature, and pressure. If it weren’t for that program, I wouldn’t have Bootcamp installed on my Mac. So I know enough about Windblows to give myself a stomach ache. Since the formula has been in the article for years and hundreds of thousands of visitors with IE7 read the article without complaint, and since IE7 is being replaced by IE8 and the IT people at your work will eventually catch up on that too, and since this rendering bug effect doesn’t appear with any other browser, it seems to be unique to that particular computer at your work running IE7. So do you think it is worth futzing over? Greg L (talk) 01:12, 13 November 2010 (UTC)
See Internet_Explorer#Market share history overview by year and version. IE7 is with us for some time to come, like it or not. But if others using it have no problems, that's fine, I'm not worried about my specific workplace. LeadSongDog come howl! 05:30, 14 November 2010 (UTC)

Do we need extensive discussion and examples about the energy and frequency equivalent of a kilogram?

I count 300 words plus a long note (note 20) to convey the following idea: "When you convert a kilogram to energy with E=mc^2, it's an awful lot of energy, compared to everyday energies. When you convert it to frequency (or "sum of photon frequencies") with f=mc^2/h, it's an awfully high frequency, compared to everyday frequencies." I don't think any of this discussion is sufficiently important or relevant for this article and I suggest taking it out.

People know intuitively how much mass a kilogram is, and that's what the kilogram is---a mass. Saying that 1kg corresponds to a lot of energy helps you understand the meaning of E=mc^2...not helps you understand "1 kg". "E=mc^2" is a different article. Likewise for frequency. Building intuition is great, but the intuition we want to build is intuition about how massive is 1kg...not how big its energy-equivalent is, not how fast its frequency-equivalent is, not how hot its temperature-equivalent is, not how delicious its Calorie-equivalent is, etc. The numbers are too big and the connection to 1kg is too indirect and unfamiliar to be helpful from an intuition point of view, in my opinion.

There's also this "sum of photon frequencies" idea ("The expression “photons whose frequencies sum to…” is a way of specifying the total energy in any collection of photons and means the sum could theoretically be that of a single photon with the specified frequency, ten photons each averaging one-tenth the specified frequency, a hundred photons each averaging one-hundredth the frequency, and so forth....") These descriptions and examples seem quite excessive, in my opinion. Photons are not part of how the watt balance works, photons have nothing to do with the kilogram. The only purpose of these sentences is to define Planck's constant for people unfamiliar with it, and can't we do it more efficiently? We can just say, "Planck's constant is a fundamental constant in quantum mechanics, that functions as a conversion factor between energies and frequencies. For example, a photon with frequency f has energy E=hf." But I don't see the reason for discussing groups of actual photons that correspond to 1kg (from a chemical oxygen-iodine laser, or the YAL-1 laser, etc.), because groups of actual photons are not how the watt-balance (or any other definition) works.

I'm not opposed to just a sentence or two that says "One concrete way of thinking about the equation f=mc^2/h, is that f is the frequency of a hypothetical photon whose energy corresponds (via E=mc^2) to m=1kg. This hypothetical photon is just hypothetical -- everyday photons have far lower frequencies -- but this description is valid in theory. In practice, the watt balance would be used to measure the correspondence between frequency and mass."

I shortened those descriptions a while ago but Greg L put them back, so I thought I should explain my reasoning and ask what other people think. Thanks!! :-) --Steve (talk) 04:55, 15 November 2010 (UTC)

I agree with User:Sbyrnes321. The current text is incorrect - the actual proposed defintion of the kilogram is 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 6.626 06X × 10-34 when it is expressed in the unit s-1•m2•kg, which is equal to J•s. - see here. The discussion about the energy equivalent of one kilogram has a place, but should be reduced to one sentence - maybe there is scope for for a new article about the implications of e=mc2. Martinvl (talk) 08:05, 15 November 2010 (UTC)
I partly agree with you two. Now…
Do you guys think I just made this stuff up as I corresponded with the guy at the NIST? I exchanged some sixty e-mails with him while working on this article. I e-mailed him drafts of what I was working on in 2007 and he reviewed that entire paragraph multiple times before signing off on it. He also e-mailed me a bunch of articles from Metrologia (by the Institute of Physics Publishing) so I could write here exactly what was in those. Those are the sources for all this stuff. But those papers aren’t available on line. What is available on line is stuff like that Powerpoint presentation you just provided. So Steve, please stop ‘playing physicist’ and stop advancing arguments about what you think is going on (like Photons are not part of how the watt balance works because the guy who’s building the watt balance understands it about a million times more than you do and you are just flat wrong.
But, yes; I agree with you about the definition and your posts here made me see that. Up until a month ago, all that stuff was absolutely correct before the October recommendation (only a month ago). Before then, there were two proposed definitions in Metrologia 42, “Redefinition of the kilogram: a decision whose time has come”: one was very generic and would stop at fixing the Planck constant and simply define the kilogram in the following terms: “The kilogram is the mass of a body at rest such that the value of the Planck constant h is exactly fixed at [x value]”. That definition, back in 2007 when I first expanded the article, wasn’t considered to be the likely winner.
The Metrologia paper also had a more “applied” definition that (of course) fixed the value of h but also stepped through the extra math associated with the only known way of practically applying that definition: “the mass of a body at rest whose equivalent energy equals the energy of photons whose frequencies sum to ( 299,792,45826.62606896×10−34 ) hertz.” That is how one applies the definition so the math logic more explicitly traces through to the watt balance. That was the definition the guy at the NIST thought would go forward. (Maybe he was a bit too close to his watt balance). And that added specificity introduces nothing new; 299,792,4582 will always be the equivalent energy of a kilogram no matter how reduced the new definition is. Ergo…
So I have some work to do to ensure that the “definition”—as proposed by the CIPM, is distinctly presented as the “definition” and how that definition translates to the watt balance (where, believe it or not, all the physics and math in the watt balance traces back to photons and their energy).
The above is my take on the matter. Although I’m not exactly *new* to this stuff, I’m not positive and I fully well expect that the metrology world has more precise language to explain this stuff. So I’m going to run the new text by the Ph.D. physicist at the NIST. The game has changed with the CIPM’s recommendation and it is time for him to review the text to ensure everything is absolutely correct in light of the CIPM proposal. And remember, the CIPM proposal is just that: a proposal; nothing is a done deal yet. So the new wording will properly cover the bases without being unduly predictive of what will or might come out in the wash. I’ll make a quick revision today and then run that by the NIST guy for comment. It will probably take several days to get his feedback folded into the article.
As for the expansive explanation of the sum of photon frequencies, it’s a hard concept to grasp and you guys are quite familiar with it and understand it fully. Please try to remember that this article is optimized for the 12th grade reading level and assumes a general-interest readership that has no advanced expertise in physics and math. That stuff has been in the article for years without complaint even though it receives about 2,200 hits per day. Attempts to strip it down would just make the concept abstruse for much of our readership.
Oh, BTW. Please note our Fuzzball (string theory) article. I don’t work like many wikipedians where I assume I’m so darn smart that I can read crap out of Popular Mechanics and look at Powerpoint presentations and then pull Original Research stuff out of my butt. I had many e-mail exchanges and spoke with Dr. Samir Mathur (the guy who advanced the theory) on the phone. He reviewed and signed off on every darn thing in that article. He also offered to assign a graduate student to help me if I wanted to expand the article with advanced-formula-stuff (I didn’t). Nevertheless, I had to later defend the article against a wikipedian who wasn’t a published reliable source and didn’t have a Ph.D. in astrophysics who thought he Had It All Figured Out®™©, knew better than Samir, and wanted to editwar over the nature of fuzzballs. (*sigh*) Greg L (talk) 16:27, 15 November 2010 (UTC)

P.S. This might take an extra day or two. The first thing I notice is that Powerpoint presentation is far from authoritative. Since the 2006 CODATA value for h is 6.62606896(33)×10−34 J·s, it isn’t surprising to see the value shown in the Powerpoint presentation, which has it rounded to 6.6260693×10−34 J·s. Nevertheless, I’m going to find out the true facts before anything ‘goes to print’ and get citations to sources like Metrologia. I just now wrote the guy at the NIST regarding this.

I also have to go get the {val} template fixed. Someone screwed around with it; that should have been grouped like “6.626 0693” instead of having a single hanging digit. Greg L (talk) 16:47, 15 November 2010 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── Update I’ve already received a response from the NIST researcher. Explaining the theory of operation underlying the watt balance and how it exploits gravity isn’t easy under the best of circumstances. Doing so using language that is accessible to a general-interest readership, and without sacrificing scientific rigor is double-tough. Clearly, the watt balance does not directly deal with Planck constants, nor does it directly measure the energy equivalence of a kilogram (21 megatons of energy would blow out the resistors). He’s gonna noodle on it some and is also looking up the exact wording from the CIPM. Greg L (talk) 19:12, 15 November 2010 (UTC)

There is an article Watt balance which describes the workings of the device. The reams of trivia about the implications of E = mc2 are out of place in this article and hides a some useful stuff. Martinvl (talk) 20:33, 15 November 2010 (UTC)
Once the true facts are in, it’ll get trimmed as it is revised. What’s there now doesn’t “hide” any useful stuff. But what we do know for sure at this point is we can clarify what is “proposed future definition” vs. what is “no longer proposed for a definition”. I was tempted to go out on a limb and use that the wording in the Powerpoint presentation on the assumption it has the correct value (level of precision) for h. But it is a truly ancient document dating to 2007. The Ph.D. researcher is still digging up the actual proposal so it is better to remain mute on the value until it is confirmed with a good citation. Other citations will come as they’re made available (a matter of days). About an hour ago, I received a bunch of abstruse, overly-advanced stuff from the Ph.D. researcher at the NIST. As I’ve done before, I have to digest what he gave me, try to translate it into plain-speak that is (far more) accessible to a general-interest readership, and run drafts by him to see if my translation maintains scientific rigor. It is too difficult a process, but requires some time and can be a major imposition on the Ph.D., particularly now that things are in a state of flux over there. Greg L (talk) 22:46, 15 November 2010 (UTC)
P.S. I trimmed the watt balance section to the bare bones based on a couple of e-mails I received today from the watt balance guy at the NIST. The part that reads “electric power would be directly identical to mechanical power by definition rather than being a derivative” came from him but I re-worded what he wrote so it needs to be double-checked. I’m gonna ask him to review what’s there and use that as a starting point for any future growth. Once things have settled down a bit with the basic facts, then we can focus on citations, the first new citation being for the CIPM’s actual proposal. Greg L (talk) 00:04, 16 November 2010 (UTC)
I have added a "Main article" link to the Watt balance where I think that a lot of the material that has been added by Greg L belongs. Martinvl (talk) 12:20, 16 November 2010 (UTC)
  • The guy at the NIST wrote back that what is in the article now on the watt balance is pretty good. He is still going to get back to me with the exact wording of the CIPM recommendation. That shouldn’t be too hard as he will be in France for the next two weeks. Greg L (talk) 00:38, 20 November 2010 (UTC)

Short-term instability - possible mistake

"What is known specifically about the IPK is that it exhibits a short-term instability of about 30 µg over a period of about a month in its after-cleaned mass.[18]" - from what I think is the BIPM's source for this,, it seems to be more like 4 µg over a period of about four months for the IPK (figure 14 in that document). The proceedings linked in footnote 18 give no source for the much higher value. —Preceding unsigned comment added by (talk) 06:16, 23 November 2010 (UTC)

The current citation buttressing that text is as follows:

Report to the CGPM, 14th meeting of the Consultative Committee for Units (CCU), April 2001, 2. (ii); General Conference on Weights and Measures, 22nd Meeting, October 2003, which stated “The kilogram is in need of a new definition because the mass of the prototype is known to vary by several parts in 108 over periods of time of the order of a month…” (3.2 MB ZIP file, here)

As mere wikipedians, we are not reliable sources who can second-guess the CCU’s report to the CGPM. Your observation is interesting. But merely pointing to a report written by Girard and making the observation that it doesn’t mention the 30-day instability does not mean that the CCU was not privy to information other than the report to which you linked. Greg L (talk) 00:04, 13 December 2010 (UTC)

ampere-force section

Could someone double-check that my changes to the ampere-force section [10] are correct? Also, would this proposal, if accepted make the coulomb, not the ampere, a base unit? CS Miller (talk) 19:55, 26 January 2011 (UTC)

  • Yes, thank you. It was an in-depth analysis. Remember though, ampere-based forced has no chance in the world of being adopted; it is a dead-end road. Whereas an expanded treatment of the watt balance is in order since it is the air apparent for taking over from the IPK, an abstruse and intricate treatise on a dead-end technology is not. Moreover, Wikipedia is an encyclopedia directed to a general-interest readership; an eight-step analysis linking newtons to amperes to coulombs, etc. (a multi-step process that needed other editors to double check your work) was not sufficiently accessible to a general-interest readership. Sometimes, using simple plain-speak and keeping it short is more effective. Greg L (talk) 22:47, 26 January 2011 (UTC)


The tone of the discussion of the Watt balance and alternative new definitions seems to be very biased in favor of the Watt balance. Recent press accounts appear to show that the metrology community considers the alternatives (or at least the silocon shpere approach) to be equally viable. Should we try to fix the POV? -Arch dude (talk) 01:46, 31 January 2011 (UTC)

Can you give some references please? The CCU (who are a committee of the CIPM and therefore who have a lot of influence within the BIPM) favour basing the definition on Planck's constant (and therefore the watt balance by implication). Martinvl (talk) 06:26, 31 January 2011 (UTC)
Sure. Here: Nature News:Kilogram adjustment courts controversy. -Arch dude (talk) 15:17, 31 January 2011 (UTC)
The watt balance is the only alternative that has a prayer and is the only alternative to the IPK seriously being considered now. The article you pointed to makes just that point and clearly shows that the watt balance is the only promising show in town. The other approaches have been abandoned. The work on the Avogadro project continues just to correlate the magnitude of the mole with results from the watt balance. The other approaches ground to a halt years ago. The question is only if and when the watt balance gets good enough to replace the IPK. If the watt balance doesn’t make the cut, then the metrology world will stay with an SI system founded upon a hunk of metal longer still. If you have evidence (which I know you don’t because no one could) that one of the other approaches is actually seriously being considered by the professional metrology world and the BIPM, tell us about it.

In the mean time, we don’t give equal play to the other approaches just because they have their own subsections in this article and that somehow makes them deserving of equal weight—go tell that to the German researchers who worked on the atom-counting approach with gold atoms (a total dead end). You think I just made this stuff up? I exchanged over 60 e-mails with the Ph.D. researcher who’s making the NIST’s watt balance when growing this article from the über-crap it used to be. Everything is sufficiently cited.

If you have evidence that some other approach is seriously being considered—even if it’s Popular Mechanics (right beside the story about flying cars that are coming soon)—let us know and we’ll see if we can solve the apparent conflict over the basic facts with a more authoritative citation. Greg L (talk) 00:55, 1 February 2011 (UTC)

Hey, I'm just a non-professional with an interest in science. The article I referenced seems to indicate that the silicon-polishers are still in contention against the watt-balancers. You appear to be correct with respect to any other approaches, but our WP article makes it appear that the silicon-polishers are just as misguided as the atom-counters, and this is not supported by the NatureNews article I referenced. From that article it appears that that Avagodro Project would contend that they are trying to fix the Avogadro number and determine Plank's constant experimentally, while the Watt balance works the other way. I'm too ignorant to see a difference here. -Arch dude (talk) 01:09, 1 February 2011 (UTC)
The fact that you have exchanged 60 e-mails with the researcher is prima facie evidence that you should not be excersise great care when editing this article. WP is supposed to be a tertiary source. This means that the editors are supposed to rely on published, citable secondary sources, not primary sources such as personal communications with researchers. I hope you do keep editing, but editors with personal knowledge have a special obligation to rigidly adhere to WP policy in this regard. Let be soften that. Scientifically knowledgeable editors such as yourself are a precious resource, and I personally prefer to give such editors a lot of leeway. -Arch dude (talk) 01:20, 1 February 2011 (UTC)
Thanks. I try my best to not abuse the privileged access I have to the horse’s mouth. I did the same at Thermodynamic temperature. Do you see that first citation there, to Daniel C. Cole? I exchanged numerous e-mails with him and he fed me text for me to build upon and reviewed my text before I posted it. Taking abstruse “Ph.D.-talk” and converting it into plain-speak that A) is accessible to a general-interest readership, and B) maintains scientific rigor, is not easy. Not easy at all. Same too with Fuzzball (string theory); I not only e-mailed the Ph.D. researcher behind that theory (Dr. Mathur), I spoke to him on numerous occasions while writing that article. As for this article, every single important point in the article is properly cited—most of it to Metrologica. What every source (including the researcher) are saying is that no one in the professional metrology world contemplates changing the definition of the kilogram from a platinum cylinder that doesn’t oxidize to a silicon sphere that does; that would be one giant step backwards, not forwards. But, as you pointed out, the “silicon polishers” (the Avagodro Project) are providing crucial information to cross-check the magnitude of the dalton so that the mole can be cross-checked with the kilogram, which can be cross-checked with the mechanical watt, which can be cross-checked with the electrical watt, so there is a single definition power and that definition will—when acceleration of gravity is factored into it all—delineate the kilogram. Greg L (talk) 01:47, 1 February 2011 (UTC)

P.S. With regard to the silicon-polishers are just as misguided as the atom-counters, the Avogadro Project first started as an attempt to redefine the kilogram in terms of the molecular weight of silicon. I see now that the original citation is now broken, but the second source in that citation still works so this article from ACPO in Australia still reflects the original ambitions of the Avogadro Project: As the Web site still says (before they take that one down too) is as follows: “The proposition of the Avogadro Project is to redefine the kilogram in terms of the Avogadro constant”. Though the Avogadro people might strenuously object (there is healthy competition for funding for projects that keep Ph.D.'s with something to do), it is clear that no one is seriously proposing any more to define the kilogram in terms of atom-counting approaches. So now, the Avogadro Project serves a valuable cross-checking to discern the value of the Avogadro constant, which in turn will help determine the proper value to use for the Planck constant and the magnitude of the kilogram. Greg L (talk) 01:59, 1 February 2011 (UTC)

My reading of the Nature News article is that the article is NOT discussing the question "what is the best way to redefine the kilogram?", it is discussing the question "if the kilogram is redefined by setting a physical constant to a defined value, what should the value be?". The latter is controversial because different experiments are inconsistent with each other. So I guess I agree with Greg L, this source does not show that there is any problem with the article's attitude that the watt balance approach is the universally-preferred candidate redefinition. Unless we can find another source... --Steve (talk) 07:04, 1 February 2011 (UTC)

I think that this discussion is best carried out on the talk page of New SI definitions. BTW, I have added that article to the SI template. Martinvl (talk) 09:25, 1 February 2011 (UTC)