Talk:Conversion of units/Archive 2005

Article bloat

I think it is time to discuss and try to reach some consensus on the scope of this article. I'll throw out some of my suggestions to get the ball rolling. For example, when editing it we get a message about trying to restrict it to 32 kilobytes, and we could easily do so.

If nobody cares enough to discuss it, I'll just start editing in accordance with these principles.

• This article should only list units which have seen some significant use in the 20th century or later, at least in some geographical location or field of activity. Leave the rest to medieval weights and measures or ancient weights and measures.
  • In his 1790 report to the House of Representatives, Thomas Jefferson made this characterization:[1] "coomb, dry; this last term being ancient and little used." This unit has seen no revival since then.

• There is no need to list every variant definition in use.
  • Yes or no?
    • The difference between imperial gallons and U.S. liquid gallons, yes.
    • The difference between the international foot and the 1893-1959 U.S. foot still used in USGS surveys, debatable.
    • The difference between the Paris pied (foot) and the Quebec pied, definitely not. In this case, neither unit has been used before the 20th century, so I'd say they don't belong here at all.
  • Include one or two identified variants of the Btu and the calorie; leave the rarely used ones to the respecive articles on the units.

• There is no need to list every historical variation in the definitions. Leave that to the specific article on that unit.
  • The distinction made here between torrs and millimetres of mercury is silly. Both names are used now with the definition listed under torr; both names were used in the past with the older definition listed under millimetre of mercury. Combine both names under the current definition.

• When compound units include a component of time, volume, or area, there is no need to list every possible combination of hours, minutes, seconds, years, etc.; nor every Cubic centimetre, millilitre, cubic millimetre, decilitre, cubic metre, etc. Pick the ones in common use; forget the others.

Gene Nygaard 19:16, 2 Jan 2005 (UTC)

I agree that a lot of conversion factors could/should be pushed out to the relevant articles (e.g. the various feet). Key variants such as the U.S. vs Imperial values ought to be kept, that is obvious. So should the U.S. Survey units —at the very least the mile ("statute mile"). The distinction between torr and mmHg may seem silly to some, but is nevertheless real.

The problem with paring the list down, farming sublists out to articles, and so on, is that one then no longer has the convenient master list in one place. If we're worried mostly about the list's size, the first step should be to make each section into a separate page (e.g. "Conversion of units (Volume)" and so on). Similarly, removing some divisions (per minute, per hour, per day, etc.) for convenience's sake is no good —one user's most frequently used magnitude won't match another, depending on context. Flow rates in oceanography won't be in the same ranges as flow rates for home air infiltration measurements, for example. In that sense, "common use" is not definable.

Urhixidur 00:13, 2005 Jan 3 (UTC)

There are not two different units called "torr" and "millimeter of mercury". There is an older definition for this unit under either name based on a conventional density of mercury at 0 °C, and there is the current definition of this unit under either name as 1/760 of a standard atmosphere defined as 101.325 kPa. Torr and mmHg only have one joint Wikipedia article, and quite properly so. Historical variations can be dealt with on that page, just like no-longer-used definitions of feet.

Most of what I'm talking about should not be "farmed out"; some could be made clearer in the individual articles linked to here.

I have no problem with flow rates or various other combinations of units actually used to some significant extent. Many of them listed here are not.

This article is linked to from other articles to provide guidance in making conversions from units that might be encountered in that context, and as a reference source for those Wikipedia editors trying to add conversions to measurements already existing in other articles.

It doesn't need to be cluttered up with useless things such as inches and leagues based on the U.S. survey foot, which are never used.

It doesn't need every historical variation in different units.

Things which are not units of measurement

• It doesn't need trivia like various multiples of wine bottle sizes, never used as "units of measurement" as such but only as particular standard sizes, and furthermore which varied in size depending on the size of the prevailing "standard bottle" (now 750 mL, not the size used here).
• Other things never actually used as "units of measure" include "link (Ramden's, Engineer's)" where link can be used to refer to a physical part of the measuring device, but the results of the measurement are expressed in "feet"—units already listed here and readily available for conversion. Whenever "link" and "chain" are used as units of measurement, it is a virtual certainty that it is "Gunter's chain" that is referred to. There is absolutely no ambiguity to worry about.

Gene Nygaard 16:38, 26 Jan 2005 (UTC)

I was expecting a nice list of conversion factors (or whatever they're called) from SI and Metric units to Imperial and US units. What I found was that, plus a list of conversions from SI units to units in which nobody has ever measured anything in my lifetime (have you ever heard someone say "This car's output is an amazing eleven buckets of coal at 5000 RPM in 5th gear" ?? I think not.).. ... And on top of that, a great list of alternative but equivalent things..... How about we just pick out the one or two commonly used Metric/Imperial/US/SI units and stick with them alone? We all know how many seconds go into a minute, yes??

foot-pound-force per hour, foot-pound-force per minute, foot-pound-force per second - These all seem like fair and reasonable things to include in the article, but.... I don't know. Really I'm just being an ass. Is there a neater way to present this information maybe?

If nothing else, I can say I'm pretty sure that this article looks very hard to maintain!! (I did find what I was looking for, though)

125.236.211.165 (talk) 13:52, 26 August 2008 (UTC)

Correct conversion to coulombs?

What is the correct conversion factor from faradays to coulombs? Faraday says 96485.3415, but conversion of units says 96485.3383. Is either one of these an "accepted" conversion value? (message posted to Talk:Faraday and Talk:Conversion of units.) --bdesham 13:58, 8 Apr 2005 (UTC)

I would guess that it depends on the actual definition of those Fred Flintstone units (faradays) which is being used, something that is time-dependent and field-of-activity-dependent. Do you remember the days when faradays were still used, and when physicists defined atomic weight differently from the way chemists defined it, when both were different from the current unified atomic mass unit? Gene Nygaard 14:05, 8 Apr 2005 (UTC)

No, I'm far too young for that :-) In any event, though, the article(s) should be changed to reflect the potential differences in the definition of the faraday—I'd do it myself, but obviously, I don't know enough to do that. --bdesham 18:56, 8 Apr 2005 (UTC)