Talk:International System of Units/Archive 1

message: Although SI units are (largely) based on the Metric system they should be considered distinct as there are notable differences:
Temperature: SI= Kelvin; Metric =Celsius
Volume: SI = dm3; Metric = liter/litre
(these are not the same as would first appear as a liter of distilled water and kg of distilled water are the same thing and the volume in SI units will vary with temperature).
Distance: SI = metres only, Metric versions such as Km, cm etc. are not permitted. similar to weight in SI where it is always measured in Kg.  grams, Tonne atc. not used.
Energy is always in Joules in SI units -never Kcal. 
Additionally some non-metric units are SI units such as s (seconds).  Attempts for a metric time measurment were, for obvious reasons, abandoned shortly after the French first considered it.
Dainamo March 14,2004
:The SI most certainly does permit km, cm, etc.  They are SI derived units, a standard part of the system and notated with SI prefixes.  They are not SI base units, but they are part of the system.  For the purpose of allowed units, SI is the same as all other metric systems; the only thing that differs is which are considered the base units and which are considered the derived units, which is unimportant in practice (it's only important for the definition and maintenance of reference values). --Delirium 02:13, May 25, 2004 (UTC)
::You are indeed correct in the above observation, however that does not deflect from the fact that, although based largely on the metric system,  SI units should not be considered as the same thing.  Liters/Litres, Celcius are two measures not permitted as SI units and the SI units of seconds is never metric.  Furthermore there are other fundemental differences such as Kg being a metric measure of weight but of mass in SI units.  The concept of weight relies both on mass and gravatational force which are different.  Hence a 60kg man may say he remains 60kg on the moon in SI units but he would not be incorrect to say he "weighs" appropriately less in Kg in using metric due to the reduced gravatational force.  I am not being pedantic but a distinction between the systems is needed to avoid potetnial inaccuracy
: By the way, the litre and the dm3 are exactly the same, and have been since 1964. --Jeepien 17:22:20, 2005-08-04 (UTC)
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I think "SI" is a better page name that "International_System_of_Units" -- a huge number of articles here refer to it as SI. Principle of least astonishment etc -- Tarquin 21:57 Jan 8, 2003 (UTC)
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Just a little something about the transition from imperial to metric: I have on several locations/occations in Australia seen various 'metric' notations...
Example: "75 sqklms land for sale!" Instead of much simpler 75 km2
-- Gorm
:I think this is due to people not being able to type km2 (This is common in cases where the ad is produced from information stored in a database). - 211.28.160.221
:That still is a rather redarded way to abbreviate km²; km*km would be much preferable. Of course, if one wanted to be funny, one could always write km² as GL/m. Mkweise 01:27, 18 Nov 2003 (UTC)
thread_title: Metric Units are not SI Units

message: I see that the SI base units have a separate page, however I'd also like to see them listed briefly here, perhaps in table form.  Is there a reason I shouldn't do so?  --zandperl 17:30, 17 Mar 2004 (UTC)
thread_title: Base units

message: The table of derived units is inconsistent about whether to use the solidus ("/") or negative indices, but I'm too lazy to fix it myself.  Anyone?  ,,,Trainspotter,,, 22:43, 21 Sep 2004 (UTC)
thread_title: Derived units table

message: Did Simon Stevin invent the idea of Metric systems in 1585 in his book 'De Theinde' - predating the current article's promotion of the French invention in 1640? Should the article be amended to reflect this historical point? Ian Cairns 22:51, 17 Oct 2004 (UTC)
replies: text: Simon Stevin advocated the idea of using decimals for monetary and measurement purposes, but he didn't invent the idea of Metric systems. --PieIsIrrational 07:17, 21 Nov 2004 (UTC)
thread_title: Invention of the SI / Metric System

message: This prompted the establishment of a new temperature scale, called the absolute scale or Kelvin scale, which relocates the zero place but still uses 100 kelvins between the freezing point and boiling point of water.
The Kelvin scale is but one absolute scale.  Then there's the Rankine scale.  Also this sentence seems to imply that the Kelvin scale is in part based on the difference in temperature between the freezing and boiling points of water at atmospheric pressure.  This is not the case as the article goes on to point out.  This needs a rewrite. - Jim 16Mar05
:It is most certainly "in part based on the difference between the freezing and boiling points of water"; pretty much totally based on that, in fact.  How would you propose rewording it to make your point, that that's not what we look to to determine the size of kelvins now?  Gene Nygaard 08:57, 16 Mar 2005 (UTC)
thread_title: Kelvin

message: I'm reverting the addition to a link to a conversion calculator recently added for several reasons.  It's probably somebody's self-promotion, but it isn't significant even to worry about that.
#One isn't really necessary here.  If anywhere, maybe conversion of units.
#Even the Google calculator offers more and is easier to use
#This one has nothing to recommend it over hundreds of similar mediocre calculators available.
##This calculator only includes simple quantities.  Not even units of force are included, let alone more complicated things such as energy or pressure.  All it includes is length, volume, and mass.,
##It is U.S.-centric even there, with unidentified "gallons" and the like the only option.
##It is sloppily constructed.  If you click on the link to convert those unidentified gallons to liters, it prompts you for "Grams"!!!
I thinks that's reason enough to throw it out.  If the proponent wants to discuss it here, fine. Gene Nygaard 18:48, 25 Mar 2005 (UTC)
thread_title: Link to mediocre external calculator