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It would hugely benefit this article to have a formal statement of purview in the lead or shortly thereafter.
There's not a single thing in this article about conventions of metric notation in formal writing. It's seems to me reading this that the purview of metric is to provide a comprehensive set of ranged units for physical measurement and a standardized notation for expressing these ranged units, but it doesn't seem to have much to say about whether one correctly writes "2L jug" or "2 L jug" or "2-L jug" or "2 litre jug" or "2-litre jug".
Is this formally outside the bailiwick of the metric system? There is a section covering this in the SI article. Is it SI itself that extends the metric system with these niceties?
Surely someone eminent must have once sat down and said "this is our scope". What was stipulated?
Do countries legally adopt metric or do they legally adopt SI, or do they implicitly adopt metric via SI, or do they formally adopt both as separate entities? How does that work?
Do scientific journals say "we expect you to use metric" or do they say "we expect you to use metric measurements written in notation as codified by SI" or do they say "we expect you to conform to the national standard, which is presently Metric/SI"? Why does that make me think of GNU/Linux? — MaxEnt 03:03, 1 August 2014 (UTC)
> The metric system has been officially sanctioned for use in the United States > since 1866, but it remains the only industrialised country that has not > adopted the metric system as its official system of measurement.
This is false. The USA adopted the metric system in 1866 and it has the same official legal status as the US Customary system (in fact, the customary system is defined in terms of SI). What you really mean to say is that the USA has not banned the US Customary system. — Preceding unsigned comment added by 174.125.234.34 ( talk) 17:43, 27 November 2014 (UTC)
Hi, I have been following the movement towards Metrication in the United States, and I have read some recent news. There is a proposed bill in Oregon to require State agencies to use the International System of Units by January 1, 2018, if the bill passes. I strongly suggest that this bill and movement in Oregon is mentioned somewhere in the article, because if this bill passed, it would really mix things up about Metrication in the United States. Here is more information about the proposed bill in Oregon. Also ( AzaToth), I suggest the map of the U.S. (image below), be split into 50 states, with Oregon highlighted as Yellow (instead of grey), meaning a proposed bill could switch the system of measurements to the International System of Units. Here is another link to the Oregon International System of Units bill. Thanks! CookieMonster755 (talk) 23:11, 1 March 2015 (UTC)
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Jc3s5h, in your edit comment you asked for an explanation of the deletion of a citation. [1] [2] My reply is that it is an inappropriate citation in the paragraph "original metric system" because it doesn't support the statement at all. So it is better to cleanup. Ceinturion ( talk) 13:02, 3 June 2016 (UTC)
On New Year's Day "Burma" was changed to "Myanmar" in the article. I'm not sure this is valid. Both names are commonly used in English. Jimp 04:25, 14 October 2016 (UTC)
On that map up top, how come Antarctica is shown? It isn't a country to adopt or not adopt the metric system. — Preceding unsigned comment added by 198.203.84.2 ( talk) 14:26, 7 December 2016 (UTC)
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why don't use Scientific Units, SU, instead. is there any other "scientific" units? [I don't mean SU v.1.0 ( ͨ m, gr, "h) ].
Tabascofernandez (
talk)
01:08, 15 July 2017 (UTC)
In the edit summary of this edit @ Swpb: asserts that Metric system is the primary topic for Metric. But if that were true:
Also, where is the discussion where it was agreed that this is the primary topic? -- Dr Greg talk 21:43, 26 October 2017 (UTC)
Here we have the symbol for the are as "are" - it was just restored to that after being changed to "a". While in the Hectare article it is stated to be "a" (in the caption to a diagram and in the tables). Neither this article or that one has an RS to support it though. So which is correct? -- DeFacto ( talk). 15:51, 10 December 2017 (UTC)
The metrics system is fundamentally a system of unit measures for everyday use. The MOST significant thing is what are those units? We have at least the obvious ones: length, weight, time and an electrical unit, and a few miscellaneous ones. The niceties of how they related to each other are next, but secondary to most peoples' direct experience of it. Yet, no mention of the fundamental units is in the lead. Sbalfour ( talk) 05:08, 16 January 2018 (UTC)
Fixed, by adding a first paragraph of description. Now what we have though is a paragraph of description followed by four paragraphs of mostly history. This is an article about science, not history. The rest of the lead can be scratched, or integrated into the history section if it makes sense. The metric system has a set of very recognizable properties. Where are they? Most people have never heard of CGPM - it doesn't belong in the lead. They wouldn't recognize the metre des archives if it fell in their soup - no need to mention it in the article at all. Most people probably wouldn't know that speed and acceleration for example aren't actually part of the system - how do they fit in? Sbalfour ( talk) 05:49, 16 January 2018 (UTC)
OK, now the lead has a science-like description of the metric system in the initial paragraphs, but it is untenable long, at least twice as long as a suitable lead needs to be. I think the best fix is to just move all the old paragraphs into the History section, and pull up any details relevant to the system as it exists today, as if the system had just popped into existence yesterday. There is a whole article devoted to history, History of the metric system, and arguably, ALL history from this article should be moved there. Since that article exists and is long and good, what column space we have here should be devoted to the science. Sbalfour ( talk) 16:34, 16 January 2018 (UTC)
Done - essentially the lead has been rewritten to reflect the science rather than the history, and history from the lead moved to the history section. The lead is 7 paragraphs, and that is unconventionally long. However, it is 23 lines of about 20 words, about average as leads go. If form is valued over function, the paragraphs can be split and merged to obtain 4 paragraphs of 5.5 lines each, quite normative for the encyclopedia. But compositionally, that'd be a disaster.
If some of the "summarized" content doesn't actually exist in the article, then the article itself needs better coverage, because the essentials of the metric system as a science are stated in the lead. Sbalfour ( talk) 17:49, 16 January 2018 (UTC)
I can't see what useful purpose having a history section here can serve. That history is in three parts, which are the primary content of three other articles: Original metric system ( History of the metric system), International adoption ( Metrication) and International standards ( International system of units). What can we usefully say here that isn't even more useful in those articles? Writing scholarly text is hard work; isn't that hard work better spent elsewhere? The encyclopedia's cluster-like structure of articles around a topic means each article needs to set and maintain a tight focus. It's a question of where the information is MOST expected to be found, and that's where we should put it. That keeps duplication of effort and column space to a minimum. I think the most logical action is to strike the history from the article; the other articles are large and detailed, and there isn't anything here that can be meaningfully merged there.
Future developments is also a history section of sorts, and covered both in International system of units and History of the metric system articles, as well as Proposed redefinition of SI base units. So now we have 4 copies of that piece.
What might be usefully said in a history here, from the top? Not another narrative (we already have 2, because there's also one in International system of units History section). Maybe some kind of structural history, rather than a narrative one, which aids in understanding the scope of the metric system as a science, and as a human endeavor. It should say something not said as such elsewhere, and be strictly limited in length - 3-5 paragraphs are more than enough. This article not about history. Sbalfour ( talk) 18:16, 16 January 2018 (UTC)
I would write something like this here:
The history of the metric system is a bit more than 200 years. It spans four eras: the latter part of the Age of Enlightenment, the Age of Science, the Industrial era, and the modern age. It begins in 1792, with an experiment in measurement, a survey of earth's meridian in order to use a fractional part of it as a unit of length. It extends through at least 1960, with the introduction of the modern metric system.
The first metric system in Revolutionary France was two-dimensional; it defined units of length and mass. A third dimension, that of time, was recognized early in the 19th century. Together they constituted a system of mechanical units that were the basis of several metric systems over the next 70 years, including most the variants we know today. But the systems were fragmented because they were missing a more subtle unit, an electrical one, identified just after the turn of the 20th century. These units formed an integral and substantially complete system.Two auxilliary units were added in mid-century, along with a number of derived units, and it became the modern metric system.
It emphasizes units over properties of the system, so needs revising. But it's an informative overview, one not available elsewhere. Sbalfour ( talk) 00:46, 17 January 2018 (UTC)
No mention of the EMU, ESU, Gaussian, International system, or Heaviside-Lorentz systems of electrical or electrical+mechanical units. We still use some of these today in special fields. The first complete three-dimensional system of mechanical units did not have a name, and was that of Gauss around 1832, and its units were gram, millimeter, and second. It existed until around 1873, with the definition of the CGS system by the British Association for Advancement of Science. Sbalfour ( talk) 18:36, 16 January 2018 (UTC)
Under this section, we have a subsection International system of units. The International system of units is not a variant of the metric system - it is the metric system, the only one that can be meaningfully called that for ordinary purposes. It should have its own level 2 section. Variants are essentially part of history - there are no variants today, with piddling exceptions. The Variants section can probably be subordinated to the History section (if one remains in the article), or if not, subordinate to the (raised) International system of units section, since they are essentially precursor variants of it. We don't want to draw attention to these, they're a distraction from the science and should not remain as a level 2 structuring section - they're not a structuring part of the metric system. Sbalfour ( talk) 22:24, 16 January 2018 (UTC)
I'm not sure I can divine from the whole section that the kilogram standard is still a man-made artefect. It's the largest impediment to advancement of the metric system, and should be stated in the first or second sentence.
The length of the meter is now defined in terms of the speed of light, and "can be reproduced by any suitably equipped laboratory." This is an article about everyday science for the man-in-the-street. The metre or metre-stick is the most recognizable object on all of earth. I'm in a laboratory with a flashlight, mirrors, a stop watch and measuring tape (possibly in feet and inches) and I need to make a metre. Now what? To the average person, it doesn't make sense to define any length in terms of the speed of light, because we can't "see" it move. Even a college-level physics laboratory won't be equipped to measure the speed of light well enough to make a reasonable metre. The reader walks away from the article with the vague feeling he should know something he wasn't told. These things are so familiar yet so far way. An article like this should make science accessible. It could be explained, in just a few sentences, how the technology is used. No, it won't enable someone to go down in their basement and make a meter, but it would make it believeable that a competent physicist with precision equipment could do it. The encyclopedia isn't a "how-to" manual, as the purists would object. But sometimes, a little of the how-to is necessary to convey understanding. In this case, it is understanding that it is both possible and useful to define a meter as some fraction of the disance light travels in some unit of time.
Realisability is a subsection under features, parallel to things like coherence. It's not actually a "feature" of the metric system. It's the flip side of the whole science, the experimental side. No, they're not independent - it's not very useful to define something if we can't make one, nor is it useful to make something because it's easy and use that as a definition, because such a definition may not be useful. Making a ball of mud is very easy, but defining a kilogram as such a thing is not very good. The section needs its own structuring level 2 section. Things like base/derived units, coherence, rationalization, decimalization, etc are the properties of the system.
Sbalfour ( talk) 19:24, 16 January 2018 (UTC)
The subsection Universality is mislabeled - it's about history, not science. I'm not sure what it should be called, but it belongs in the history section. I've already noted above that the subsection Realisability needs it's own level 2 section, and doesn't belong here.
The design properties of the metric system are enumerated in a paragraph of the redrafted lead. There are about 6:
There are a few more auxiliary properties not so much a part of the design as the applicability: as stated, universality; rationally related units; and extensibility. Rationally related units is not so obvious: in the 19th century International system of units, the unit of length was 107 meters, and the unit of mass 10-11 grams. These are not rationally related, so the system wasn't very practical for anything but its electrical units. Universality is more about making concessions to existing systems of measure by allowing units of those systems alongside the metric system or giving them definitions in terms of the metric base units so that the metric system is usable by all. Extensibility in practice means that it's easy to add new base and derived units to the system as has been done.
There's also an implicit completeness axiom that defines the system: the 4 electromechanical base units together can measure any known quantity. In the 19th century, it was believed that only three were required, and the system fell into chaos. We have three other base units which are defined today, but are not independent. Some explanation for why these exist and make sense is part of the science.
Each of the 6 primary properties needs it's own subsection here. An additional subsection could cover the applicability aspects. An insider who knows the science can write the last subsection, possibly an interpretive one, on the character of the non-orthogonal base units.
Sbalfour ( talk) 20:33, 16 January 2018 (UTC)
The first and largest (unamed) section under this heading isn't about the science, but about adoption or metrication. There's even a hatnote telling us that. It belongs under History, in the subsection International adoption which it's directly a part of.
This whole article is terribly muddled about what's pure science, what's applied science (metrication), and what's history. If I threw out everything that's not science, I think the article would shrink by 2/3 or even 3/4. I have to say, given the structure of the encyclopedia now, that metrication is not a proper aspect of this article. There are at least 10-12 articles about metrication, and more appear regularly. Surely one or more of those is where that information is expected to be found. What usefully can we say about metrication or adoption here? Maybe it's worth a bare few paragraphs but not more. The fragmentation of the encyclopedia is daunting,but that's what we have to work with.
Sbalfour ( talk) 21:10, 16 January 2018 (UTC)
This is an article about the metric system, I'd say the lead one, or the one at the top of the pyramid, the one with the broadest scope and most content. The one likely to attract the most eyeballs, where most people will come for their information. So I come here to get answered a simple question: what are the units? How about litre, foot and pound? Maybe not? Well, then what are they? All of them, because there's only a few, so I hear. A list, or a sentence giving their names and possibly their dimensions. I suppose each of their names is mentioned somewhere at least once, but even if I find some of them, how do I know I got them all? And well, there's a rather longer list of derived ones, so maybe a bullet list, or a modest table. It's sadly disturbing that neither can be found here. That info is found somewhere else, and how will the reader know where that is? And even if it is, the reader is here, and this is where he should be. This is the main article for the metric system. Laser beam to the brain. What's the content? Sbalfour ( talk) 22:05, 16 January 2018 (UTC)
A man buys a sack of flour, and it's labeled "one kilogram". He weighs it, and the scale says "2.2 pounds". But someone told him that a kilogram is a unit of mass, not weight. Should a kilogram weigh 2.2 pounds? So he figures maybe the difference is something like that between dry and wet ounces. The merchant might've labeled the bag that way in order to cheat him, figuring he won't know the difference anyway. He doesn't know if he's being cheated, but he's dubious. Can this article resolve the problem? That's surely science. A kilogram is not a unit of weight, though it will surely weigh a kilogram (2.2 lbs in this case).
Will it ever matter for practical purposes? An analogous case is that of a pendulum clock whose pendulum is about .994 meter. If you take that clock to the equator (or the north pole) or just about anywhere, it will no longer keep accurate time, and it will be noticeable after a few days. For the same reason, taking a kilogram of flour to the north pole will result in it no longer weighting 2.2 lbs. But a kilogram of flour, properly measured anywhere on earth, will be the same amount of flour as a kilogram of flour at the north pole. Does that matter? A scientist will not take 2.2 lbs of any substance to the north pole. He will take a kilogram.
Somewhere in the article, this bit of science should be done, because all of our customary systems of weights and measures include a unit of weight (or several) and man-in-the-street, even one in a metric world, may not have a good notion of what the metric unit of mass really means.
Sbalfour ( talk) 22:58, 16 January 2018 (UTC)
Now it has become clear from my remarks, what the structure of the article should be. The topic of the article is one about science, so information on metrication and history should be dispatched to articles on those topics. The level 2 structuring sections are as follows:
1. units
2. Realization of units
3. properties as a system
4. International system of units
5. metric system in the real world (glitches and gotcha's)
6. conversion table
That's about the right number of level 2 structuring sections. In my experience, it should be 5-8, no more. Before writing, or reorganizing, it helps to lay it out, so subtopics become apparent.
Sbalfour ( talk) 23:30, 16 January 2018 (UTC)
Sbalfour ( talk) 04:50, 17 January 2018 (UTC)
All customary systems of weights and measures since the days of Charlemagne and as far back as the classical civilizations of Greece and Rome, included a measure of weight, often several. As we now know, the weight of an object is the force of earth's gravity on it. Gravity was unknown until Newton's Principia in 1687, so the weight of an object was regarded as a fundamental property, and was the same everywhere. Newton told us that the earth does not have uniform shape, and that as a consequence, the force of gravity varies by latitude and altitude. The metric system does not have a unit of weight, but one of mass.
An object in outer space loses its weight, but not its mass. If a weightless rock is thrown in outer space and strikes an object, it will strike with force. The object has a property which does not depend on earth's gravitation. That property is mass. Mass is an intrinsic dimension of matter. An object's mass is proportional to the amount of matter in it. That amount can be determined very precisely by the amount of force over time required to accelerate the object to a specified velocity. Its mass is therefore referred to as its inertial mass, when the context leaves room for ambiguity. An object's inertial mass is the same everywhere on earth, and anywhere in the universe as far as we know. An object's mass can be weighed, but that weight represents the local force of earth's gravity upon it, not its mass. Earth's gravity varies by only a few parts in 1000 over the surface of the earth (from pole to equator), and a scale capable of measuring that would typically be found only in a scientific laboratory.
Like so many of these related articles, this one includes an assortment of organization and political/administrative body names. Here's a partial list (I probably missed a few):
This article on science can be written in a way that is fully accessible and richly detailed without any of those names. I have written the lead; it covers most things of importance in a topical way, and does not mention any of them. A couple of those names appear ten times or more in the article. Only one of those names, CGPM is worth a mention in the article, and that sentence should be to carefully define its mission with respect to the science. It could be in a sidebox rather than embedded in the article. Organizations don't do science; men do. And there are not so many men mentioned in the article. Saying those names are vital to the science is equivalent to saying if the organization changes name or ceases to exist, some part of the science becomes invalid.
The article can also be written without mentioning the names of any of the historical men of science - their place is in the companion article on history. I do think it would focus editors on writing about science rather than organizations, people, proposals, administration and other things. There's also a bad habit of popping in names we know nothing about, forcing the reader to jump to another article (if it's wikilinked, and it may not be), back and forth for each name. A sentence like "Kelvin proposed in 1848..." where it's the first mention of the name. Instead, "19th century English scientist William Thompson (Lord Kelvin, for whom the SI unit Kelvin is named) proposed ..." The date of the proposal might be important, but likely not. We can also say, more meaningfully, "In the middle of the 19th century, the bottom of the Kelvin scale was established at -2730C, very close to its known value today." We don't need to know the name, or it could be put in a footnote, so we focus on the science rather than the person.
I know why editors write these kind of things: it's much easier to write a factoid: "The CIPM proposed <such and such> ..." than to write about science. To write about science, one has to think. To write a factoid with a name, one only has to copy. It's scarier still to think the editors don't actually know the science, they only know what they copy.
I'm going to rephrase the article to get rid all the organization names, and move most of the person names if they are meaningful, into footnotes, else into the article on history Sbalfour ( talk) 18:16, 17 January 2018 (UTC)
I enlarged the section considerably, now I think I regret it. I added a section on MKS, for example, which is WAYYYYY more important then Gravitational systems. Still, the longest running and only standards-based metric system while it existed, is not listed. Right: the French system of 1799 which lasted at least through the 1873 definition of the CGS system by the BAAS. New standards weren't fashioned until 1889, so figuratively, it lasted 90 years. The French system doesn't exist anymore, but the Gaussian (EMU + ESU) system is still in active use in theoretical physics. However, the whole level 2 section is now a chunk of history. Given the anemic level of science in the article generally, should we be taking a sharp left turn into history here? There's already a whole article on the International system of units, which has been proposed to be merged here, so we of necessity need to be summary in this section. What exactly should be the content until that merge is completed? Anything written will become a future burden to merge.
Sbalfour ( talk) 19:56, 17 January 2018 (UTC)
Too many names, too much history, too much wind. Funny how those go together. Oh, in case I forgot, not very much science. How, exactly do you count a second in vibrations of the cesium atom? How does one 'catch' light and break it into meters? We go into our basement laboratory, and conduct a scientific experiment. What do we have there, and what do we do with it? That's science. High schoolers learning science come here. They don't know how it can be meaningful to define a meter in terms of something intangible like light. We can give them that understanding. And no, they won't be able to conduct a useful experiment to make their own meter, but they might be able to conduct some other experiments related to other base units.
Some raw facts are pertinent to this section. But most pertinent is an understandable explanation of wny units are realized the way they are, and some physics as to how they do that. Sbalfour ( talk) 21:36, 17 January 2018 (UTC)
It says: None of the other base units rely on a prototype – all are based on phenomena that are directly observable... That's wind. What would be a prototype of an ampere? A lightning bolt in a jar? Is an ampere directly observable? It's precisely because the dimensional manifestation of electromagnetism is not directly observable that it took about a century for an electrical unit to be recognized as the fourth essential component of an electromechanical system of units. The ampere is NOT realized the way it was in 1881, which is the impression gotten from the text. What should actually be said here? One unit, Kelvin, isn't mentioned at all (a temperature scale which is not part of the SI is mentioned instead). mole and candela are mentioned by name, but no description of how they are realized is given. I'm in a laboratory, and need to measure one of these things. What do I do? Only the second has a satisfactory description of its realization, and it's buried in a heap of history. That sentence gets to stay; the rest of the subsection is superfluous.
This section (and the one for metre and kilogram, which should probably be merged into this one), ostensibly should consist of two things: a statement of how the unit is defined, which is a realizable relationship, and a statement of how to get from that relationship to an SI unit usable where it is needed, i.e. a laboratory procedure. The definitions may appear elsewhere, like in the Units section (which previously did not exist), in which case only the statements about laboratory realization need appear here, and which currently none do. How do you get from vibrations of a cesium atom to a clock that ticks in seconds? It matters practically as well as theoretically: we had to change the definition of candela because it was in practice not very reliably replicable. So now it is not very meaningful, but can be very accurately measured. The definitions tend to converge to realizable representations, but the definitions themselves are NOT the realizations. So this entire section is essentially vacant of appropriate content.
Sbalfour ( talk) 18:49, 18 January 2018 (UTC)
Here's the basic thesis: realization of units of measurement proceeded through 4 stages of refinement.
The first was observable phenomena of nature. The most convenient and omnipresent object in nature was a human being. Hence we got foot, span, cubit, toise, etc. Weights were usually defined in terms of volume of some substance, especially volumes of a monetary substance like silver. Realization of a unit was the unit: a span is a hand, etc. Long distances were defined in terms of the Roman stride or double-step. A thousand Roman strides was (and is) a mille = 1000 strides, or mile. Roman soldiers didn't carry toise-long iron bars around to measure miles. But measures based on nature aren't very reproducible because nature isn't actually all that constant as we learned with pendulums in the 16th century.
So standards used in trade tended to be artefacts that replicated familiar quantities from nature. Man-made artefacts represented the second stage of refinement of measures. But the problem remained. When an artefact deteriorated or was lost, a new standard had to be made, one taken from original circumstances in nature. Or someone somewhere else, who didn't have access to the standard, made one of their own using knowledge of how the standard was derived. Everyone has a foot, but not everyone's foot is the same.
Starting in the middle of the 20th century, we had scientific laboratories that could very accurately measure things using synthetic quantities like wavelength of characteristic spectral lines of some substance. This isn't exactly a phenomenon of nature. There's nothing natural at all about krypton-86; we have to make and purify it in a laboratory. But the excitation wavelength is very precise; that from all krypton-86 atoms will be exactly the same. So synthetic phenomena represent the third stage of refinement of measures. But even synthetic phenomena can vary somewhat. The excitation energy of krypton-86 can affect the wavelength of the spectral line. So an implicit part of the definition is that excitation energy.
But there are some things that are truly invariant in the physical world, though they may be measurable only in a laboratory. They lie at the core of existance. They are relations between matter, energy and the quantum properties of space. Things like the speed of light and Boltzman's constant. They can be very precisely known, because directly or indirectly they define the results of all scientific experimentation. There are only a very small number of such truly invariant things. But in terms of them, everything else that does vary can be defined. That is the fourth stage in refinement of measures, and we are very close to that today.
Sbalfour ( talk) 23:02, 17 January 2018 (UTC)
History is another article. The history here was a mishmash of history of the science, history of adoption, and history of administration by the CGPM and subsidiary organizations. Editors who sincerely wish to work on that can help us out in the history articles. Editors who work here, can now focus on the science. Sbalfour ( talk) 20:43, 18 January 2018 (UTC)
B. Fairbairn, there are at least five problems with this addition of yours - in no particular order:
I propose reverting this addition. -- DeFacto ( talk). 16:14, 3 January 2019 (UTC)
The units of R are NOT m²/s² but 0,000258 C/kg Roentgen_(unit). It is just silly to put it in one box with rad and gray! Ra-raisch ( talk) 11:55, 2 February 2019 (UTC)
My understanding of the Metric System is that the gram, not the kilogram, is the base unit of 'Mass' measurement. — Preceding unsigned comment added by Drlambert100 ( talk • contribs) 19:38, 12 February 2019 (UTC)
"It is now known as the International System of Units (SI)."
Really? My understanding has always been that the litre, tonne, hectare and bar are part of the metric system, though not part of SI. Furthermore, here in the UK, probably elsewhere as well, a lot of consumable products would be in breach of regulations if the litre weren't a metric unit.
Furthermore, if they were synonyms, why would there be a separate International System of Units article? — Smjg ( talk) 15:38, 10 August 2019 (UTC)
@ Lithopsian: Wikipedia has multiple redundant articles on metric systems. Articles it does not need. But it has none on metric units as a concept (describing all metric units, regardless of system). Then when I create one you delete it. Why? Dondervogel 2 ( talk) 20:12, 13 February 2020 (UTC)
Can anyone explain why SI "doesn't fit here"? (and yet cgs still does). I certainly can't, thus I've reverted it. Explanations and opinions invited. Andy Dingley ( talk) 17:56, 17 February 2020 (UTC)
Metric system refers to the internationally recognised decimalised system of measurement known as the International System of Units (SI), or to one of its predecessors.I do think there's to much focus on the SI here, and that's unnecessary, as there is already an excellent article on the SI itself. The correct solution is to deemphasize the SI, and refocus this article on the metric system more generally. Tercer ( talk) 09:32, 18 February 2020 (UTC)
My objective was to structure the article with headings something like below, with simple summaries and reference to main articles where they already exist.
A Metric system is any one of the systems of measurement that succeeded the decimalised metre-based system introduced into France in the 1790s. The most recent such system is the internationally recognised International System of Units (SI). Background French revolution, etc... Principles Realisation (units based on the natural world) Base and derived unit structure Decimal ratios Prefixes for multiples and submultiples Coherence Rationalisation Variants Gaussian second and the first mechanical system of units EMU, ESU and Gaussian systems of electrical units Centimetre–gram–second systems International system of electrical units MKS and MKSA systems Metre–tonne–second systems Gravitational systems International System of Units See also References External links
What do others think? -- DeFacto ( talk). 11:42, 18 February 2020 (UTC)
The article contains the following sentence: "The International System of Units has been adopted as the official system of weights and measures by all nations in the world except for Myanmar, Liberia, and the United States, while the United States is the only industrialised country where the metric system is not the predominant system of units."
Given that:
I guess we need to either rework it into a factually accurate sentence, and provide reliable sourcing for it, or remove it from the article altogether. I propose removing it for now - rather than potentially misleading readers, pending a consensus over a new wording or removal. -- DeFacto ( talk). 20:43, 22 February 2020 (UTC)
Let's pause this, and the flood of sources below. We still need the article to reflect the fact that if this Australian goes to the UK I encounter a place with a bit of a mixture of units, but where everybody understands the metric system, and metric units are commonly available for almost everything. This is simply not the case in the US. When I visit America I have to dig out of my ageing brain all those pounds, yards and gallons that I haven't used for 45 years. Not a criticism of anyone, mind you. Just a reality to observe and describe. Let's not pretend the US and the UK are alike on this front. HiLo48 ( talk) 01:59, 23 February 2020 (UTC)
@ DeFacto: asked "How would you answer NIST's charge that the CIA factbook is helping to peddle those myths?" Ever since the Metric Conversion Act of 1975 NIST has tried to pretend that the US was going metric, and that US government agencies were doing what they were supposed to do under that and subsequent acts. But NIST is living in a fantasy world and their claims about the extent to which the US in general, or federal government agencies in particular, have adopted SI are unreliable. Jc3s5h ( talk) 02:37, 23 February 2020 (UTC)
the coordinator of NIST's Metric Program. Because of my passion for all things metric..., which explains why it is advocating for this fantasy. Moreover, its argument that the US has adopted the metric system is simply that the US units are defined in terms of SI units. That's laughable. Tercer ( talk) 12:12, 23 February 2020 (UTC)
After our promising "new start" with this article, Tercer has now chosen to revert the lead back to the earlier poor quality version that has been discredited. I reverted it back to the new starter version, explaining the purpose of the lead, but was quickly re-reverted back again.
In that last revert, Tercer asserted that this is how the lead was for years, when the article was WP:GOOD.
Well if we look at the
diff between the 'GA' version and the current Tercer version we see that actually, the lead in the then 'good' version's was very different from this. In the 'good' version we had "The metric system has been officially sanctioned for use in the United States since 1866" and "Although the United Kingdom uses the metric system for most official purposes, the use of the imperial system of measure, particularly in unregulated sectors such as journalism, is widespread", for example (which also echoes the views I added to what we've been discussing at
Talk:Metric system#Questionable sentence about adoption of the SI system). And the 'good' version lead had none of the irrelevant stuff about the British imperial system or the US customary system being defined using the metric system.
So perhaps we could revert back to the pre-Tercer lead again as a basis for serious improvement, and stop this unnecessary disruption. The lead should reflect the article, not contain stuff not mentioned in the article, and is ideally created after the article content has stabilised. -- DeFacto ( talk). 22:30, 26 February 2020 (UTC)
|comment=
and |nosection=
template parameters could be used to capture the consensus about the editing context? It could help reduce this kind of thing – I made an edit earlier without first reading the talk page. OTOH, does anyone intend to work on it in a way that justifies use of the template? —
Quondum
15:53, 14 March 2020 (UTC)
I think we need to start from scratch and remember that the lead should summarise what is already there in the body, and not introduce material otherwise absent. Here's my humble offering to start the ball rolling:
-- DeFacto ( talk). 20:45, 14 March 2020 (UTC)
Two authors have now made the claim that there are more than seven SI base units - without any references. I will quote an edit summary: "it is widely known the SI includes multiple derived units (pascal, hertz, watt to name but a few)" I would suggest that both authors read SI base units and relevant citations in that article. The claim that the pascal, hertz, and watt are base units suggests a serious lack of WP:COMPETENCE in this subject - they are all described as derived units in the lead of their respective articles. The claim that "it is widely known ..." reveals a similar lack of understanding of Wikipedia policies. Suggesting that I tag the article is not a sufficient excuse for reinstating statements without references after they have been challenged. Should I tag it and then delete it because it lacks a reference? Seriously, get it together and demonstrate with reliable sources that I'm an idiot, or take a pause and think about what you're doing. Lithopsian ( talk) 20:27, 9 March 2020 (UTC)
[[Lumen (unit)|lumen]] (W<sup>-1</sup>),
. This gives the impression that lumens are simply reciprocal watts. It just isn't that simple.
Jc3s5h (
talk)
18:34, 10 March 2020 (UTC)
The recent additions are more of a description of the culmination of the development of metric systems than of metric systems in general. The idea of having base units as central is not really a principle, but a convenient way of expressing that dimensions form a vector space with a basis, and choosing a basis for it. A statement such as "There should be a single base unit of measure for quantities of each of the fundamental dimensions of nature" is, well, like saying that there are fundamental x-, y-, and z-directions in nature. Let's not systematize the historical metric systems. That there were a limited number of independent dimensions was recognized in the development of the various metric systems, but all we can say is that the systems were built on the understanding that known dimensions could be expressed in terms of a limited number of independent dimensions. Even the number of independent dimensions considered was not uniform: CGS-Gaussian didn't have an independent dimension for electric and magnetic charge, just as we need not have an independent dimension for time (due to the very fundamental Poincaré symmetry of local spacetime. We need to be careful about inserting synthesized/editorial material. — Quondum 16:54, 22 April 2020 (UTC)
Note that Giorgi here actually runs afoul of Bridgman's principle of nearly absolute freedom to choose one's dimensions. Bridgman would not think there is anything particularly strange about electrical resistance having the dimensions of velocity (or its inverse), and would not think that anything other than sheer convenience recommends the systems where electrical quantities are represented by a fourth dimension over the older, purely mechanical three-dimensional systems.In the meantime [i.e. roughly coinciding with Heaviside's development of Maxwell's electromagnetic theory], the theory of physical dimensions was beginning to be better understood, and the opinion was no longer held that everything in the physical world depended necessarily on three fundamental mechanical dimensions. Physicists recognised that entropy, temperature, loudness of a sound, light intensity, etc., brought into play some dimensions which were not dependent on [L], [M], [T]. Why ought not electric and magnetic magnitudes to be treated in the same way? The pretention of making them dependent on length, mass and time has led to such strange consequences of attributing to electrical resistance the dimensions of a velocity (in the electromagnetic system) or of the reciprocal of a velocity (in the electrostatic system). Accordingly, the principle of having a fourth fundamental dimension entering into the electric and magnetic magnitudes gradually became universally recognised. An independent dimension means also an independent and arbitrary unit; but this conclusion was not drawn at once.
The modern absolute system of physical measurement is founded upon dynamical notions, and originated with C. F. Gauss. We are for the most part concerned in studying motions in nature; and even when we find bodies at rest in equilibrium it is because the causes of motion are balanced rather than absent. Moreover, the postulate which lies at the base of all present-day study of physics is that in the ultimate issue we must seek for a mechanical explanation of the facts of nature if we are to reach any explanation intelligible to the human mind. Accordingly the root of all science is the knowledge of the laws of motion, and the enunciation of these laws by Newton laid the foundation of a more exact knowledge of nature than had been possible before. Our fundamental scientific notions are those of length, time, and mass. No metaphysical discussion has been able to resolve these ideas into anything simpler or to derive them from each other. Hence in selecting units for physical measurements we have first to choose units for the above three quantities.
This article inconsistently uses a definite or an indefinite article - "the metric system" versus "a metric system". The rest of Wikipedia seems to use a definite article, e.g. Outline of the metric system. This article should either use a definite article consistently, like the rest of Wikipedia, or explain in the introduction what the difference is. Gaiacarra ( talk) 12:34, 28 April 2021 (UTC)
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Archive 1 | Archive 2 | Archive 3 | Archive 4 |
It would hugely benefit this article to have a formal statement of purview in the lead or shortly thereafter.
There's not a single thing in this article about conventions of metric notation in formal writing. It's seems to me reading this that the purview of metric is to provide a comprehensive set of ranged units for physical measurement and a standardized notation for expressing these ranged units, but it doesn't seem to have much to say about whether one correctly writes "2L jug" or "2 L jug" or "2-L jug" or "2 litre jug" or "2-litre jug".
Is this formally outside the bailiwick of the metric system? There is a section covering this in the SI article. Is it SI itself that extends the metric system with these niceties?
Surely someone eminent must have once sat down and said "this is our scope". What was stipulated?
Do countries legally adopt metric or do they legally adopt SI, or do they implicitly adopt metric via SI, or do they formally adopt both as separate entities? How does that work?
Do scientific journals say "we expect you to use metric" or do they say "we expect you to use metric measurements written in notation as codified by SI" or do they say "we expect you to conform to the national standard, which is presently Metric/SI"? Why does that make me think of GNU/Linux? — MaxEnt 03:03, 1 August 2014 (UTC)
> The metric system has been officially sanctioned for use in the United States > since 1866, but it remains the only industrialised country that has not > adopted the metric system as its official system of measurement.
This is false. The USA adopted the metric system in 1866 and it has the same official legal status as the US Customary system (in fact, the customary system is defined in terms of SI). What you really mean to say is that the USA has not banned the US Customary system. — Preceding unsigned comment added by 174.125.234.34 ( talk) 17:43, 27 November 2014 (UTC)
Hi, I have been following the movement towards Metrication in the United States, and I have read some recent news. There is a proposed bill in Oregon to require State agencies to use the International System of Units by January 1, 2018, if the bill passes. I strongly suggest that this bill and movement in Oregon is mentioned somewhere in the article, because if this bill passed, it would really mix things up about Metrication in the United States. Here is more information about the proposed bill in Oregon. Also ( AzaToth), I suggest the map of the U.S. (image below), be split into 50 states, with Oregon highlighted as Yellow (instead of grey), meaning a proposed bill could switch the system of measurements to the International System of Units. Here is another link to the Oregon International System of Units bill. Thanks! CookieMonster755 (talk) 23:11, 1 March 2015 (UTC)
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Jc3s5h, in your edit comment you asked for an explanation of the deletion of a citation. [1] [2] My reply is that it is an inappropriate citation in the paragraph "original metric system" because it doesn't support the statement at all. So it is better to cleanup. Ceinturion ( talk) 13:02, 3 June 2016 (UTC)
On New Year's Day "Burma" was changed to "Myanmar" in the article. I'm not sure this is valid. Both names are commonly used in English. Jimp 04:25, 14 October 2016 (UTC)
On that map up top, how come Antarctica is shown? It isn't a country to adopt or not adopt the metric system. — Preceding unsigned comment added by 198.203.84.2 ( talk) 14:26, 7 December 2016 (UTC)
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why don't use Scientific Units, SU, instead. is there any other "scientific" units? [I don't mean SU v.1.0 ( ͨ m, gr, "h) ].
Tabascofernandez (
talk)
01:08, 15 July 2017 (UTC)
In the edit summary of this edit @ Swpb: asserts that Metric system is the primary topic for Metric. But if that were true:
Also, where is the discussion where it was agreed that this is the primary topic? -- Dr Greg talk 21:43, 26 October 2017 (UTC)
Here we have the symbol for the are as "are" - it was just restored to that after being changed to "a". While in the Hectare article it is stated to be "a" (in the caption to a diagram and in the tables). Neither this article or that one has an RS to support it though. So which is correct? -- DeFacto ( talk). 15:51, 10 December 2017 (UTC)
The metrics system is fundamentally a system of unit measures for everyday use. The MOST significant thing is what are those units? We have at least the obvious ones: length, weight, time and an electrical unit, and a few miscellaneous ones. The niceties of how they related to each other are next, but secondary to most peoples' direct experience of it. Yet, no mention of the fundamental units is in the lead. Sbalfour ( talk) 05:08, 16 January 2018 (UTC)
Fixed, by adding a first paragraph of description. Now what we have though is a paragraph of description followed by four paragraphs of mostly history. This is an article about science, not history. The rest of the lead can be scratched, or integrated into the history section if it makes sense. The metric system has a set of very recognizable properties. Where are they? Most people have never heard of CGPM - it doesn't belong in the lead. They wouldn't recognize the metre des archives if it fell in their soup - no need to mention it in the article at all. Most people probably wouldn't know that speed and acceleration for example aren't actually part of the system - how do they fit in? Sbalfour ( talk) 05:49, 16 January 2018 (UTC)
OK, now the lead has a science-like description of the metric system in the initial paragraphs, but it is untenable long, at least twice as long as a suitable lead needs to be. I think the best fix is to just move all the old paragraphs into the History section, and pull up any details relevant to the system as it exists today, as if the system had just popped into existence yesterday. There is a whole article devoted to history, History of the metric system, and arguably, ALL history from this article should be moved there. Since that article exists and is long and good, what column space we have here should be devoted to the science. Sbalfour ( talk) 16:34, 16 January 2018 (UTC)
Done - essentially the lead has been rewritten to reflect the science rather than the history, and history from the lead moved to the history section. The lead is 7 paragraphs, and that is unconventionally long. However, it is 23 lines of about 20 words, about average as leads go. If form is valued over function, the paragraphs can be split and merged to obtain 4 paragraphs of 5.5 lines each, quite normative for the encyclopedia. But compositionally, that'd be a disaster.
If some of the "summarized" content doesn't actually exist in the article, then the article itself needs better coverage, because the essentials of the metric system as a science are stated in the lead. Sbalfour ( talk) 17:49, 16 January 2018 (UTC)
I can't see what useful purpose having a history section here can serve. That history is in three parts, which are the primary content of three other articles: Original metric system ( History of the metric system), International adoption ( Metrication) and International standards ( International system of units). What can we usefully say here that isn't even more useful in those articles? Writing scholarly text is hard work; isn't that hard work better spent elsewhere? The encyclopedia's cluster-like structure of articles around a topic means each article needs to set and maintain a tight focus. It's a question of where the information is MOST expected to be found, and that's where we should put it. That keeps duplication of effort and column space to a minimum. I think the most logical action is to strike the history from the article; the other articles are large and detailed, and there isn't anything here that can be meaningfully merged there.
Future developments is also a history section of sorts, and covered both in International system of units and History of the metric system articles, as well as Proposed redefinition of SI base units. So now we have 4 copies of that piece.
What might be usefully said in a history here, from the top? Not another narrative (we already have 2, because there's also one in International system of units History section). Maybe some kind of structural history, rather than a narrative one, which aids in understanding the scope of the metric system as a science, and as a human endeavor. It should say something not said as such elsewhere, and be strictly limited in length - 3-5 paragraphs are more than enough. This article not about history. Sbalfour ( talk) 18:16, 16 January 2018 (UTC)
I would write something like this here:
The history of the metric system is a bit more than 200 years. It spans four eras: the latter part of the Age of Enlightenment, the Age of Science, the Industrial era, and the modern age. It begins in 1792, with an experiment in measurement, a survey of earth's meridian in order to use a fractional part of it as a unit of length. It extends through at least 1960, with the introduction of the modern metric system.
The first metric system in Revolutionary France was two-dimensional; it defined units of length and mass. A third dimension, that of time, was recognized early in the 19th century. Together they constituted a system of mechanical units that were the basis of several metric systems over the next 70 years, including most the variants we know today. But the systems were fragmented because they were missing a more subtle unit, an electrical one, identified just after the turn of the 20th century. These units formed an integral and substantially complete system.Two auxilliary units were added in mid-century, along with a number of derived units, and it became the modern metric system.
It emphasizes units over properties of the system, so needs revising. But it's an informative overview, one not available elsewhere. Sbalfour ( talk) 00:46, 17 January 2018 (UTC)
No mention of the EMU, ESU, Gaussian, International system, or Heaviside-Lorentz systems of electrical or electrical+mechanical units. We still use some of these today in special fields. The first complete three-dimensional system of mechanical units did not have a name, and was that of Gauss around 1832, and its units were gram, millimeter, and second. It existed until around 1873, with the definition of the CGS system by the British Association for Advancement of Science. Sbalfour ( talk) 18:36, 16 January 2018 (UTC)
Under this section, we have a subsection International system of units. The International system of units is not a variant of the metric system - it is the metric system, the only one that can be meaningfully called that for ordinary purposes. It should have its own level 2 section. Variants are essentially part of history - there are no variants today, with piddling exceptions. The Variants section can probably be subordinated to the History section (if one remains in the article), or if not, subordinate to the (raised) International system of units section, since they are essentially precursor variants of it. We don't want to draw attention to these, they're a distraction from the science and should not remain as a level 2 structuring section - they're not a structuring part of the metric system. Sbalfour ( talk) 22:24, 16 January 2018 (UTC)
I'm not sure I can divine from the whole section that the kilogram standard is still a man-made artefect. It's the largest impediment to advancement of the metric system, and should be stated in the first or second sentence.
The length of the meter is now defined in terms of the speed of light, and "can be reproduced by any suitably equipped laboratory." This is an article about everyday science for the man-in-the-street. The metre or metre-stick is the most recognizable object on all of earth. I'm in a laboratory with a flashlight, mirrors, a stop watch and measuring tape (possibly in feet and inches) and I need to make a metre. Now what? To the average person, it doesn't make sense to define any length in terms of the speed of light, because we can't "see" it move. Even a college-level physics laboratory won't be equipped to measure the speed of light well enough to make a reasonable metre. The reader walks away from the article with the vague feeling he should know something he wasn't told. These things are so familiar yet so far way. An article like this should make science accessible. It could be explained, in just a few sentences, how the technology is used. No, it won't enable someone to go down in their basement and make a meter, but it would make it believeable that a competent physicist with precision equipment could do it. The encyclopedia isn't a "how-to" manual, as the purists would object. But sometimes, a little of the how-to is necessary to convey understanding. In this case, it is understanding that it is both possible and useful to define a meter as some fraction of the disance light travels in some unit of time.
Realisability is a subsection under features, parallel to things like coherence. It's not actually a "feature" of the metric system. It's the flip side of the whole science, the experimental side. No, they're not independent - it's not very useful to define something if we can't make one, nor is it useful to make something because it's easy and use that as a definition, because such a definition may not be useful. Making a ball of mud is very easy, but defining a kilogram as such a thing is not very good. The section needs its own structuring level 2 section. Things like base/derived units, coherence, rationalization, decimalization, etc are the properties of the system.
Sbalfour ( talk) 19:24, 16 January 2018 (UTC)
The subsection Universality is mislabeled - it's about history, not science. I'm not sure what it should be called, but it belongs in the history section. I've already noted above that the subsection Realisability needs it's own level 2 section, and doesn't belong here.
The design properties of the metric system are enumerated in a paragraph of the redrafted lead. There are about 6:
There are a few more auxiliary properties not so much a part of the design as the applicability: as stated, universality; rationally related units; and extensibility. Rationally related units is not so obvious: in the 19th century International system of units, the unit of length was 107 meters, and the unit of mass 10-11 grams. These are not rationally related, so the system wasn't very practical for anything but its electrical units. Universality is more about making concessions to existing systems of measure by allowing units of those systems alongside the metric system or giving them definitions in terms of the metric base units so that the metric system is usable by all. Extensibility in practice means that it's easy to add new base and derived units to the system as has been done.
There's also an implicit completeness axiom that defines the system: the 4 electromechanical base units together can measure any known quantity. In the 19th century, it was believed that only three were required, and the system fell into chaos. We have three other base units which are defined today, but are not independent. Some explanation for why these exist and make sense is part of the science.
Each of the 6 primary properties needs it's own subsection here. An additional subsection could cover the applicability aspects. An insider who knows the science can write the last subsection, possibly an interpretive one, on the character of the non-orthogonal base units.
Sbalfour ( talk) 20:33, 16 January 2018 (UTC)
The first and largest (unamed) section under this heading isn't about the science, but about adoption or metrication. There's even a hatnote telling us that. It belongs under History, in the subsection International adoption which it's directly a part of.
This whole article is terribly muddled about what's pure science, what's applied science (metrication), and what's history. If I threw out everything that's not science, I think the article would shrink by 2/3 or even 3/4. I have to say, given the structure of the encyclopedia now, that metrication is not a proper aspect of this article. There are at least 10-12 articles about metrication, and more appear regularly. Surely one or more of those is where that information is expected to be found. What usefully can we say about metrication or adoption here? Maybe it's worth a bare few paragraphs but not more. The fragmentation of the encyclopedia is daunting,but that's what we have to work with.
Sbalfour ( talk) 21:10, 16 January 2018 (UTC)
This is an article about the metric system, I'd say the lead one, or the one at the top of the pyramid, the one with the broadest scope and most content. The one likely to attract the most eyeballs, where most people will come for their information. So I come here to get answered a simple question: what are the units? How about litre, foot and pound? Maybe not? Well, then what are they? All of them, because there's only a few, so I hear. A list, or a sentence giving their names and possibly their dimensions. I suppose each of their names is mentioned somewhere at least once, but even if I find some of them, how do I know I got them all? And well, there's a rather longer list of derived ones, so maybe a bullet list, or a modest table. It's sadly disturbing that neither can be found here. That info is found somewhere else, and how will the reader know where that is? And even if it is, the reader is here, and this is where he should be. This is the main article for the metric system. Laser beam to the brain. What's the content? Sbalfour ( talk) 22:05, 16 January 2018 (UTC)
A man buys a sack of flour, and it's labeled "one kilogram". He weighs it, and the scale says "2.2 pounds". But someone told him that a kilogram is a unit of mass, not weight. Should a kilogram weigh 2.2 pounds? So he figures maybe the difference is something like that between dry and wet ounces. The merchant might've labeled the bag that way in order to cheat him, figuring he won't know the difference anyway. He doesn't know if he's being cheated, but he's dubious. Can this article resolve the problem? That's surely science. A kilogram is not a unit of weight, though it will surely weigh a kilogram (2.2 lbs in this case).
Will it ever matter for practical purposes? An analogous case is that of a pendulum clock whose pendulum is about .994 meter. If you take that clock to the equator (or the north pole) or just about anywhere, it will no longer keep accurate time, and it will be noticeable after a few days. For the same reason, taking a kilogram of flour to the north pole will result in it no longer weighting 2.2 lbs. But a kilogram of flour, properly measured anywhere on earth, will be the same amount of flour as a kilogram of flour at the north pole. Does that matter? A scientist will not take 2.2 lbs of any substance to the north pole. He will take a kilogram.
Somewhere in the article, this bit of science should be done, because all of our customary systems of weights and measures include a unit of weight (or several) and man-in-the-street, even one in a metric world, may not have a good notion of what the metric unit of mass really means.
Sbalfour ( talk) 22:58, 16 January 2018 (UTC)
Now it has become clear from my remarks, what the structure of the article should be. The topic of the article is one about science, so information on metrication and history should be dispatched to articles on those topics. The level 2 structuring sections are as follows:
1. units
2. Realization of units
3. properties as a system
4. International system of units
5. metric system in the real world (glitches and gotcha's)
6. conversion table
That's about the right number of level 2 structuring sections. In my experience, it should be 5-8, no more. Before writing, or reorganizing, it helps to lay it out, so subtopics become apparent.
Sbalfour ( talk) 23:30, 16 January 2018 (UTC)
Sbalfour ( talk) 04:50, 17 January 2018 (UTC)
All customary systems of weights and measures since the days of Charlemagne and as far back as the classical civilizations of Greece and Rome, included a measure of weight, often several. As we now know, the weight of an object is the force of earth's gravity on it. Gravity was unknown until Newton's Principia in 1687, so the weight of an object was regarded as a fundamental property, and was the same everywhere. Newton told us that the earth does not have uniform shape, and that as a consequence, the force of gravity varies by latitude and altitude. The metric system does not have a unit of weight, but one of mass.
An object in outer space loses its weight, but not its mass. If a weightless rock is thrown in outer space and strikes an object, it will strike with force. The object has a property which does not depend on earth's gravitation. That property is mass. Mass is an intrinsic dimension of matter. An object's mass is proportional to the amount of matter in it. That amount can be determined very precisely by the amount of force over time required to accelerate the object to a specified velocity. Its mass is therefore referred to as its inertial mass, when the context leaves room for ambiguity. An object's inertial mass is the same everywhere on earth, and anywhere in the universe as far as we know. An object's mass can be weighed, but that weight represents the local force of earth's gravity upon it, not its mass. Earth's gravity varies by only a few parts in 1000 over the surface of the earth (from pole to equator), and a scale capable of measuring that would typically be found only in a scientific laboratory.
Like so many of these related articles, this one includes an assortment of organization and political/administrative body names. Here's a partial list (I probably missed a few):
This article on science can be written in a way that is fully accessible and richly detailed without any of those names. I have written the lead; it covers most things of importance in a topical way, and does not mention any of them. A couple of those names appear ten times or more in the article. Only one of those names, CGPM is worth a mention in the article, and that sentence should be to carefully define its mission with respect to the science. It could be in a sidebox rather than embedded in the article. Organizations don't do science; men do. And there are not so many men mentioned in the article. Saying those names are vital to the science is equivalent to saying if the organization changes name or ceases to exist, some part of the science becomes invalid.
The article can also be written without mentioning the names of any of the historical men of science - their place is in the companion article on history. I do think it would focus editors on writing about science rather than organizations, people, proposals, administration and other things. There's also a bad habit of popping in names we know nothing about, forcing the reader to jump to another article (if it's wikilinked, and it may not be), back and forth for each name. A sentence like "Kelvin proposed in 1848..." where it's the first mention of the name. Instead, "19th century English scientist William Thompson (Lord Kelvin, for whom the SI unit Kelvin is named) proposed ..." The date of the proposal might be important, but likely not. We can also say, more meaningfully, "In the middle of the 19th century, the bottom of the Kelvin scale was established at -2730C, very close to its known value today." We don't need to know the name, or it could be put in a footnote, so we focus on the science rather than the person.
I know why editors write these kind of things: it's much easier to write a factoid: "The CIPM proposed <such and such> ..." than to write about science. To write about science, one has to think. To write a factoid with a name, one only has to copy. It's scarier still to think the editors don't actually know the science, they only know what they copy.
I'm going to rephrase the article to get rid all the organization names, and move most of the person names if they are meaningful, into footnotes, else into the article on history Sbalfour ( talk) 18:16, 17 January 2018 (UTC)
I enlarged the section considerably, now I think I regret it. I added a section on MKS, for example, which is WAYYYYY more important then Gravitational systems. Still, the longest running and only standards-based metric system while it existed, is not listed. Right: the French system of 1799 which lasted at least through the 1873 definition of the CGS system by the BAAS. New standards weren't fashioned until 1889, so figuratively, it lasted 90 years. The French system doesn't exist anymore, but the Gaussian (EMU + ESU) system is still in active use in theoretical physics. However, the whole level 2 section is now a chunk of history. Given the anemic level of science in the article generally, should we be taking a sharp left turn into history here? There's already a whole article on the International system of units, which has been proposed to be merged here, so we of necessity need to be summary in this section. What exactly should be the content until that merge is completed? Anything written will become a future burden to merge.
Sbalfour ( talk) 19:56, 17 January 2018 (UTC)
Too many names, too much history, too much wind. Funny how those go together. Oh, in case I forgot, not very much science. How, exactly do you count a second in vibrations of the cesium atom? How does one 'catch' light and break it into meters? We go into our basement laboratory, and conduct a scientific experiment. What do we have there, and what do we do with it? That's science. High schoolers learning science come here. They don't know how it can be meaningful to define a meter in terms of something intangible like light. We can give them that understanding. And no, they won't be able to conduct a useful experiment to make their own meter, but they might be able to conduct some other experiments related to other base units.
Some raw facts are pertinent to this section. But most pertinent is an understandable explanation of wny units are realized the way they are, and some physics as to how they do that. Sbalfour ( talk) 21:36, 17 January 2018 (UTC)
It says: None of the other base units rely on a prototype – all are based on phenomena that are directly observable... That's wind. What would be a prototype of an ampere? A lightning bolt in a jar? Is an ampere directly observable? It's precisely because the dimensional manifestation of electromagnetism is not directly observable that it took about a century for an electrical unit to be recognized as the fourth essential component of an electromechanical system of units. The ampere is NOT realized the way it was in 1881, which is the impression gotten from the text. What should actually be said here? One unit, Kelvin, isn't mentioned at all (a temperature scale which is not part of the SI is mentioned instead). mole and candela are mentioned by name, but no description of how they are realized is given. I'm in a laboratory, and need to measure one of these things. What do I do? Only the second has a satisfactory description of its realization, and it's buried in a heap of history. That sentence gets to stay; the rest of the subsection is superfluous.
This section (and the one for metre and kilogram, which should probably be merged into this one), ostensibly should consist of two things: a statement of how the unit is defined, which is a realizable relationship, and a statement of how to get from that relationship to an SI unit usable where it is needed, i.e. a laboratory procedure. The definitions may appear elsewhere, like in the Units section (which previously did not exist), in which case only the statements about laboratory realization need appear here, and which currently none do. How do you get from vibrations of a cesium atom to a clock that ticks in seconds? It matters practically as well as theoretically: we had to change the definition of candela because it was in practice not very reliably replicable. So now it is not very meaningful, but can be very accurately measured. The definitions tend to converge to realizable representations, but the definitions themselves are NOT the realizations. So this entire section is essentially vacant of appropriate content.
Sbalfour ( talk) 18:49, 18 January 2018 (UTC)
Here's the basic thesis: realization of units of measurement proceeded through 4 stages of refinement.
The first was observable phenomena of nature. The most convenient and omnipresent object in nature was a human being. Hence we got foot, span, cubit, toise, etc. Weights were usually defined in terms of volume of some substance, especially volumes of a monetary substance like silver. Realization of a unit was the unit: a span is a hand, etc. Long distances were defined in terms of the Roman stride or double-step. A thousand Roman strides was (and is) a mille = 1000 strides, or mile. Roman soldiers didn't carry toise-long iron bars around to measure miles. But measures based on nature aren't very reproducible because nature isn't actually all that constant as we learned with pendulums in the 16th century.
So standards used in trade tended to be artefacts that replicated familiar quantities from nature. Man-made artefacts represented the second stage of refinement of measures. But the problem remained. When an artefact deteriorated or was lost, a new standard had to be made, one taken from original circumstances in nature. Or someone somewhere else, who didn't have access to the standard, made one of their own using knowledge of how the standard was derived. Everyone has a foot, but not everyone's foot is the same.
Starting in the middle of the 20th century, we had scientific laboratories that could very accurately measure things using synthetic quantities like wavelength of characteristic spectral lines of some substance. This isn't exactly a phenomenon of nature. There's nothing natural at all about krypton-86; we have to make and purify it in a laboratory. But the excitation wavelength is very precise; that from all krypton-86 atoms will be exactly the same. So synthetic phenomena represent the third stage of refinement of measures. But even synthetic phenomena can vary somewhat. The excitation energy of krypton-86 can affect the wavelength of the spectral line. So an implicit part of the definition is that excitation energy.
But there are some things that are truly invariant in the physical world, though they may be measurable only in a laboratory. They lie at the core of existance. They are relations between matter, energy and the quantum properties of space. Things like the speed of light and Boltzman's constant. They can be very precisely known, because directly or indirectly they define the results of all scientific experimentation. There are only a very small number of such truly invariant things. But in terms of them, everything else that does vary can be defined. That is the fourth stage in refinement of measures, and we are very close to that today.
Sbalfour ( talk) 23:02, 17 January 2018 (UTC)
History is another article. The history here was a mishmash of history of the science, history of adoption, and history of administration by the CGPM and subsidiary organizations. Editors who sincerely wish to work on that can help us out in the history articles. Editors who work here, can now focus on the science. Sbalfour ( talk) 20:43, 18 January 2018 (UTC)
B. Fairbairn, there are at least five problems with this addition of yours - in no particular order:
I propose reverting this addition. -- DeFacto ( talk). 16:14, 3 January 2019 (UTC)
The units of R are NOT m²/s² but 0,000258 C/kg Roentgen_(unit). It is just silly to put it in one box with rad and gray! Ra-raisch ( talk) 11:55, 2 February 2019 (UTC)
My understanding of the Metric System is that the gram, not the kilogram, is the base unit of 'Mass' measurement. — Preceding unsigned comment added by Drlambert100 ( talk • contribs) 19:38, 12 February 2019 (UTC)
"It is now known as the International System of Units (SI)."
Really? My understanding has always been that the litre, tonne, hectare and bar are part of the metric system, though not part of SI. Furthermore, here in the UK, probably elsewhere as well, a lot of consumable products would be in breach of regulations if the litre weren't a metric unit.
Furthermore, if they were synonyms, why would there be a separate International System of Units article? — Smjg ( talk) 15:38, 10 August 2019 (UTC)
@ Lithopsian: Wikipedia has multiple redundant articles on metric systems. Articles it does not need. But it has none on metric units as a concept (describing all metric units, regardless of system). Then when I create one you delete it. Why? Dondervogel 2 ( talk) 20:12, 13 February 2020 (UTC)
Can anyone explain why SI "doesn't fit here"? (and yet cgs still does). I certainly can't, thus I've reverted it. Explanations and opinions invited. Andy Dingley ( talk) 17:56, 17 February 2020 (UTC)
Metric system refers to the internationally recognised decimalised system of measurement known as the International System of Units (SI), or to one of its predecessors.I do think there's to much focus on the SI here, and that's unnecessary, as there is already an excellent article on the SI itself. The correct solution is to deemphasize the SI, and refocus this article on the metric system more generally. Tercer ( talk) 09:32, 18 February 2020 (UTC)
My objective was to structure the article with headings something like below, with simple summaries and reference to main articles where they already exist.
A Metric system is any one of the systems of measurement that succeeded the decimalised metre-based system introduced into France in the 1790s. The most recent such system is the internationally recognised International System of Units (SI). Background French revolution, etc... Principles Realisation (units based on the natural world) Base and derived unit structure Decimal ratios Prefixes for multiples and submultiples Coherence Rationalisation Variants Gaussian second and the first mechanical system of units EMU, ESU and Gaussian systems of electrical units Centimetre–gram–second systems International system of electrical units MKS and MKSA systems Metre–tonne–second systems Gravitational systems International System of Units See also References External links
What do others think? -- DeFacto ( talk). 11:42, 18 February 2020 (UTC)
The article contains the following sentence: "The International System of Units has been adopted as the official system of weights and measures by all nations in the world except for Myanmar, Liberia, and the United States, while the United States is the only industrialised country where the metric system is not the predominant system of units."
Given that:
I guess we need to either rework it into a factually accurate sentence, and provide reliable sourcing for it, or remove it from the article altogether. I propose removing it for now - rather than potentially misleading readers, pending a consensus over a new wording or removal. -- DeFacto ( talk). 20:43, 22 February 2020 (UTC)
Let's pause this, and the flood of sources below. We still need the article to reflect the fact that if this Australian goes to the UK I encounter a place with a bit of a mixture of units, but where everybody understands the metric system, and metric units are commonly available for almost everything. This is simply not the case in the US. When I visit America I have to dig out of my ageing brain all those pounds, yards and gallons that I haven't used for 45 years. Not a criticism of anyone, mind you. Just a reality to observe and describe. Let's not pretend the US and the UK are alike on this front. HiLo48 ( talk) 01:59, 23 February 2020 (UTC)
@ DeFacto: asked "How would you answer NIST's charge that the CIA factbook is helping to peddle those myths?" Ever since the Metric Conversion Act of 1975 NIST has tried to pretend that the US was going metric, and that US government agencies were doing what they were supposed to do under that and subsequent acts. But NIST is living in a fantasy world and their claims about the extent to which the US in general, or federal government agencies in particular, have adopted SI are unreliable. Jc3s5h ( talk) 02:37, 23 February 2020 (UTC)
the coordinator of NIST's Metric Program. Because of my passion for all things metric..., which explains why it is advocating for this fantasy. Moreover, its argument that the US has adopted the metric system is simply that the US units are defined in terms of SI units. That's laughable. Tercer ( talk) 12:12, 23 February 2020 (UTC)
After our promising "new start" with this article, Tercer has now chosen to revert the lead back to the earlier poor quality version that has been discredited. I reverted it back to the new starter version, explaining the purpose of the lead, but was quickly re-reverted back again.
In that last revert, Tercer asserted that this is how the lead was for years, when the article was WP:GOOD.
Well if we look at the
diff between the 'GA' version and the current Tercer version we see that actually, the lead in the then 'good' version's was very different from this. In the 'good' version we had "The metric system has been officially sanctioned for use in the United States since 1866" and "Although the United Kingdom uses the metric system for most official purposes, the use of the imperial system of measure, particularly in unregulated sectors such as journalism, is widespread", for example (which also echoes the views I added to what we've been discussing at
Talk:Metric system#Questionable sentence about adoption of the SI system). And the 'good' version lead had none of the irrelevant stuff about the British imperial system or the US customary system being defined using the metric system.
So perhaps we could revert back to the pre-Tercer lead again as a basis for serious improvement, and stop this unnecessary disruption. The lead should reflect the article, not contain stuff not mentioned in the article, and is ideally created after the article content has stabilised. -- DeFacto ( talk). 22:30, 26 February 2020 (UTC)
|comment=
and |nosection=
template parameters could be used to capture the consensus about the editing context? It could help reduce this kind of thing – I made an edit earlier without first reading the talk page. OTOH, does anyone intend to work on it in a way that justifies use of the template? —
Quondum
15:53, 14 March 2020 (UTC)
I think we need to start from scratch and remember that the lead should summarise what is already there in the body, and not introduce material otherwise absent. Here's my humble offering to start the ball rolling:
-- DeFacto ( talk). 20:45, 14 March 2020 (UTC)
Two authors have now made the claim that there are more than seven SI base units - without any references. I will quote an edit summary: "it is widely known the SI includes multiple derived units (pascal, hertz, watt to name but a few)" I would suggest that both authors read SI base units and relevant citations in that article. The claim that the pascal, hertz, and watt are base units suggests a serious lack of WP:COMPETENCE in this subject - they are all described as derived units in the lead of their respective articles. The claim that "it is widely known ..." reveals a similar lack of understanding of Wikipedia policies. Suggesting that I tag the article is not a sufficient excuse for reinstating statements without references after they have been challenged. Should I tag it and then delete it because it lacks a reference? Seriously, get it together and demonstrate with reliable sources that I'm an idiot, or take a pause and think about what you're doing. Lithopsian ( talk) 20:27, 9 March 2020 (UTC)
[[Lumen (unit)|lumen]] (W<sup>-1</sup>),
. This gives the impression that lumens are simply reciprocal watts. It just isn't that simple.
Jc3s5h (
talk)
18:34, 10 March 2020 (UTC)
The recent additions are more of a description of the culmination of the development of metric systems than of metric systems in general. The idea of having base units as central is not really a principle, but a convenient way of expressing that dimensions form a vector space with a basis, and choosing a basis for it. A statement such as "There should be a single base unit of measure for quantities of each of the fundamental dimensions of nature" is, well, like saying that there are fundamental x-, y-, and z-directions in nature. Let's not systematize the historical metric systems. That there were a limited number of independent dimensions was recognized in the development of the various metric systems, but all we can say is that the systems were built on the understanding that known dimensions could be expressed in terms of a limited number of independent dimensions. Even the number of independent dimensions considered was not uniform: CGS-Gaussian didn't have an independent dimension for electric and magnetic charge, just as we need not have an independent dimension for time (due to the very fundamental Poincaré symmetry of local spacetime. We need to be careful about inserting synthesized/editorial material. — Quondum 16:54, 22 April 2020 (UTC)
Note that Giorgi here actually runs afoul of Bridgman's principle of nearly absolute freedom to choose one's dimensions. Bridgman would not think there is anything particularly strange about electrical resistance having the dimensions of velocity (or its inverse), and would not think that anything other than sheer convenience recommends the systems where electrical quantities are represented by a fourth dimension over the older, purely mechanical three-dimensional systems.In the meantime [i.e. roughly coinciding with Heaviside's development of Maxwell's electromagnetic theory], the theory of physical dimensions was beginning to be better understood, and the opinion was no longer held that everything in the physical world depended necessarily on three fundamental mechanical dimensions. Physicists recognised that entropy, temperature, loudness of a sound, light intensity, etc., brought into play some dimensions which were not dependent on [L], [M], [T]. Why ought not electric and magnetic magnitudes to be treated in the same way? The pretention of making them dependent on length, mass and time has led to such strange consequences of attributing to electrical resistance the dimensions of a velocity (in the electromagnetic system) or of the reciprocal of a velocity (in the electrostatic system). Accordingly, the principle of having a fourth fundamental dimension entering into the electric and magnetic magnitudes gradually became universally recognised. An independent dimension means also an independent and arbitrary unit; but this conclusion was not drawn at once.
The modern absolute system of physical measurement is founded upon dynamical notions, and originated with C. F. Gauss. We are for the most part concerned in studying motions in nature; and even when we find bodies at rest in equilibrium it is because the causes of motion are balanced rather than absent. Moreover, the postulate which lies at the base of all present-day study of physics is that in the ultimate issue we must seek for a mechanical explanation of the facts of nature if we are to reach any explanation intelligible to the human mind. Accordingly the root of all science is the knowledge of the laws of motion, and the enunciation of these laws by Newton laid the foundation of a more exact knowledge of nature than had been possible before. Our fundamental scientific notions are those of length, time, and mass. No metaphysical discussion has been able to resolve these ideas into anything simpler or to derive them from each other. Hence in selecting units for physical measurements we have first to choose units for the above three quantities.
This article inconsistently uses a definite or an indefinite article - "the metric system" versus "a metric system". The rest of Wikipedia seems to use a definite article, e.g. Outline of the metric system. This article should either use a definite article consistently, like the rest of Wikipedia, or explain in the introduction what the difference is. Gaiacarra ( talk) 12:34, 28 April 2021 (UTC)