Talk:Pound (mass)/Archive 2

Archive 1

Archive 2

Archive 3

UK Weights and Measures Acts

I have boldly inserted some Carriage returns into the following pertinent discussion, hopefully improving its legibility. >MinorProphet (talk) 03:41, 11 January 2011 (UTC)

I have made some alterations to the the paragraph dealing with the UK Weight & Measures Acts, but I feel that this paragraph is still inaccurate and misleading. I have not been able yet to find the text of the 1878 Act, but I suspect that it probably does not contain a quantitative comparison between the Imperial Pound and the kg.

The point is that Acts of this kind serve in the UK to define the units used by commerce, and to say that the pound Avoirdupois is the weight of a certain piece of platinum preserved in the Govt offices is sufficient for that purpose. Comparison between different standards of weight is not the business of acts of this kind, and to give two different definitions would be unhelpful. So the factual status of the paragraph needs to be checked by reference to the texts of the Acts which are mentioned there.

A further point is that the 1878 act, and all subsequent ones up to 1963 define the pound as a weight, not as a mass. The term 'weight' as used in vernacular language is ambiguous, but by the late 19th century the scientific community in Britain had decided that the term refers to a gravitational force, so for anyone who was aware of the difference, the Acts were understood to be the legal definition of a force, not a mass. The Act of 1959 defined the pound by reference to the 1878 Act, so this meaning was in force at that time, but this changed in 1963. The W & M Act of that date specifically defined the pound as a mass equal to a stated fraction of a kg. The pound therefore changed its meaning at that time, and the old imperial pound (piece of metal) became obsolete.

The meaning of the pound is absolutely clear and free of ambiguity in the UK.

Since 1963 it has been a mass; before that time it was a force. Since 1963, in order to avoid misunderstanding, the terms pound-weight (lbwt) or pound-force (lbf) have been used to refer to the weight of a pound under defined conditions (location, for example). In units of pressure or stress, the term 'pounds/square inch' is understood to be a casual abbreviation for pounds-weight/square inch, and this abbreviated usage does not imply that the pound is a unit of force.

I would like to see something of comparable clarity said about the pound in the US, but I suspect that this might not be possible since it seems that the unit has not been defined in that country with sufficient authority (comparable with an Act of Parliament) for a single meaning to be accepted by everyone. This state of affairs (if indeed it is so) should, I think, be stated clearly in the main text; acknowledgement of this ambiguity would avoid the contention expressed below in this discussion page. Dr Andrew Smith CEng

For authoritative statements that, for purposes of trade and commerce, the pound is unit of mass in the US, see Refinement of values for the yard and the pound. Also see Appendix B of NIST Handbook 44, which is adopted by all the US states for weights and measures enforcement. Appendix B makes it clear the pound is a unit of mass.

Handbook 44 does not contain any regulations that directly address force or pressure in the marketplace. It does address pressure as it affects other measurements, such as the sale of natural gas. In a number of places equivalent quantities are stated, one being given in psi, the other in kPa. Since the pascal is newtons per square meter, and the newton is a unit of force, the pound is evidently being treated as a unit of force in this context. Jc3s5h (talk) 15:51, 21 September 2010 (UTC)

I am concerned by this edit. I find the claim that a historical Weights and Measures Act defined the pound as a unit of weight in the modern technical sense very surprising. For me this raises a red flag (see WP:REDFLAG) as an exceptional claim that looks as if it came about through original research – in this case the simple assumption that the drafters of the 1878 law were using the word weight in the same way that it was used in later laws. I a asking for a qualified reliable source that states explicitly that that was the intended sense. Meanwhile I am going to mark that claim as dubious. Hans Adler 17:43, 21 September 2010 (UTC)

Hello Hans and others. Thank you for responding to my comment and edit. I am still very concerned about the assertion in the main item that the 1878 Act defined the pound in terms of the kg. I feel certain that this is incorrect, and the matter can only be settled by reference to the text of the Act. I am putting out some feelers, and will probably find it given time.

Secondly, there can be no doubt at all that the various Acts, up to 1963, defined the pound as a weight, and do not mention mass. In my comment (above) I say that by the end of the C19 'weight' was used by the scientific community in Britain to mean 'force', and on this basis I assert that the Acts (up to 1963) define, for those who are interested in the distinction, a force, not a mass. For commercial purposes, it is likely that the word 'weight' was, and still is, adequate - it refers to commonly used techniques for quantifying materials for trade, namely weighing.

The various Acts provide a means whereby these techniques can be regulated. The use of a standard weight is an essential part of this regulation, and this item is nowadays the standard kg and its various substandards. In the period and location we are discussing, this function was provided by the Imperial Pound - a specific lump of metal. It was regarded as a prototype 'weight', from which all others of its kind (pound weights, and fractions and multiples thereof) were legally derived.

I have been asked to clarify my references concerning the interpretation of 'weight' as a force and the use of the prototype pound. I will refer to 'Useful Rules and Tables' by W J M Rankine, (Professor of Engineering at Glasgow University, and originator of the Rankine Cycle), Charles Griffin & Company, London, 1889. Rankine's book is a significant reference in this context since it is the work of a distinguished academic engineer who commanded considerable respect in his era, and the work itself is intended to be a reference for practical engineers and mechanics. As such it speaks for and to an entire profession, using the language common to the profession at that time.

Rankine defines weight as a gravitational force (p 305), and on p 97 the lb is defined as the weight of a certain piece of platinum, preserved in the Exchequer Office, Westminster, under stated conditions of temperature, atmospheric pressure, and location (all pertinent to the weight of a certain mass). On p 245, Rankine defines absolute units of force (as distinct from units of weight) thus - ‘Absolute units of force in the weight of an unit of mass: in British units 32.2 nearly…’ (p 245). This can be interpreted as meaning that the absolute unit of force in the British system is ~1/32 lb-wt. Furthermore, in giving a rule for calculating centrifugal force (p 246), Rankine states - 'Multiply the weight of the mass by the square of its linear velocity and divide by the radius. The result will be in absolute units which may be converted into units of weight by dividing by g'. This rule only makes sense if 'the weight of the mass' is measured in pounds.

Thus if we take a certain mass having a weight (gravitational force) of 1 lb-wt, rotating with a speed of 1ft/sec at one foot radius, the centrifugal force will be 1 absolute unit or 1/32 lb-wt, which is correct. Conversely, if we take 'the weight of the mass' to be mg (m being the mass measured in pounds), then Rankine's Rule gives the centrifugal force as g (~32) absolute force units, or 1lb-wt, which is incorrect. This demonstrates clearly that the 'weight of the mass' is a certain number of pounds, and therefore that to Rankine and other engineers the pound is a unit of force.

Interestingly, Rankine also defines the kg as a weight - 'The Standard kilogram is the weight at the temperature of the maximum density of water... and under the standard atmospheric pressure of 760mm of mercury, in the latitude of Paris, of a certain piece of platinum which is kept in the French Archives. The use of weights founded on this standard is lawful in Briain, and a copy is kept in the Exchequer Office'. This observation casts doubt on the view that it can simply be assumed that the kg has always been a unit of mass; it seems more likely that during the C19 the standard kg served precisely the same purpose as did the Imperial Pound - i.e. it was a prototype weight.

It seems to me that Rankine's reference to temperature, pressure and latitude must have come from somewhere - presumably a formal definition of the kg by some authority or other; it is very unlikely indeed that he would have just made up these details. This in turn raises the question as to whether the Wikki entry on Pound Mass should include some comments on the historical development of the concept of mass and its relevance to the formal definition of standards of weight (including the kg); the Pound Mass and the kg mass can hardly be understood apart from their evolution. At what date, for example did the kg stop being a weight and become a mass? 'Rules and Tables' hints that this process was in motion in 1889.

For example, use of the 'absolute unit' of force seems to be a reference to the idea that force and mass can be related by Newton's Law, and that this could provide a way of defining a force unit. Thus the 'absolute force unit' of ~1/32 lb-wt was called the poundal in the foot-pound-second system, and was defined as the force required to accelerate a mass of 1lb at 1ft/sec^2. This system was in use by mechanical engineers in Britain in the 1960s and was taught in the leading engineering institutions (e.g. Imperial College London) to my personal knowledge. Similarly the dyne is the derived unit of force in the cgs system, and is defined in an analogous way (cf also the Newton in the SI). All of these definitions use the unit of mass as a primary unit, and force becomes a derived unit - a departure from the historical ideas I have outlined.

Finally I will observe that Rankine's use of the lb as a force leaves the related mass unit undefined, and I have nowhere found any comment on this in his book. The appropriate definition of the derived mass unit would be that mass which is accelerated at 1ft/sec^2 by a force of 1lb; this would be equivalent to ~32 lb-mass. I believe that this unit has been in use in some circumstances, and was termed a 'slug', but I have never seen this used in practice - it might be more familiar to some of you on the other side of the Atlantic. Dr Andrew Smith ACGI

• You have obviously spent a long time writing this comment. If you compare it with others on this talk page you will notice two major differences:
  1. It is unusually long, although some comments by Gene Nygaard in 2004 are nearly as long.
  2. It is much harder to read than even Gene Nygaard's because you have not structured it with empty lines to start a new paragraph.

This was the long version. We usually just point new editors to WP:TLDR, but that seems a bit rude.

• To keep your comments short, you can
  1. make only one or two of the most important points at a time and then wait for reactions, or
  2. spend some additional time to ensure you use your words economically. (I am not very good at this myself.)
• I have read all of it anyway, but attention is a valuable commodity hereabouts, and you have used up a lot of mine. Now I feel obliged to respond to most of your points, which I do with some reluctance.
• It is probably best if you say specifically what text you want to change how, and to use wiki markup in such a way that everybody can see your proposal at a glance.
• I think you may be under the impression that this is a contentious page and that there are on-going conflicts. That is not the case. If you look closely at the extended discussions further up on the page, you will see that almost all editors have signed their posts by writing ~~~~, which leaves the user names with links and the current date.
  • You will note that the last discussion (as opposed to short informational messages) about the article was 2 years ago.
  • Please also sign your post by writing ~~~~.
• Please keep discussion about the article on the wiki itself whenever possible. This allows other editors to contribute, and it leaves a track record for later editors who want to understand why we have approached things in a certain way. (For matters that only two editors are interested in, we sometimes use user talk pages, but generally only if the article talk page is already busy.)
• In your email to me you mentioned the possibility of creating a new article about all aspects of the pound. Please see WP:Content forking, which applies to this proposal. The proper way to approach this would be to propose merging the articles pound (mass) and pound-force. I think I would support this, but I anticipate some opposition since many editors don't understand the difference between an encyclopedia and a dictionary.
• What you write about early W&MAs sounds somewhat convincing, but I am not in a position to verify that you are not quoting selectively. When physics advanced and the original concept of weight branched into two, there must have been some terminological confusion. To some degree we still have that today. The answer to the question what the W&MA of 1878 meant by "weight" may well have a much more complicated answer than just mass or force. We will have trouble getting to a definite result if we have only sources from that time to go by. Wikipedia is not a good environment for original research, and in fact there are serious restrictions on it. See WP:NOR and also WP:PSTS for some information related to this.
• The best kind of source to decide this question would be one written by a modern historian of science. Hans Adler 10:28, 25 September 2010 (UTC)

I looked up the pound in François Cardarelli's Encyclopaedia of Scientific Weights and Measures. Here is what it says: Under "Imperial Units of Weight": "The pound avoirdupois was established under the WMA of 1856 [...] and until 1963 was defined as the mass of the Imperial Standard Pound, a platinum cylinder kept in the Standards Department of the Board of Trade in London."

It appears that the author is not originally a scholar of history of science, and it is not clear how much research went into this sentence. Therefore I am not inclined to believe him more than I believe your arguments based on the primary sources. But once we start contradicting Springer books there is reason to watch what we are saying. Hans Adler 10:57, 25 September 2010 (UTC)

Hi Hans - thank you for your comments. I value your remarks, though you are not under any obligation to read what I have written, and of course you may expend your time and energy as you think best. I feel now that my over-long contributions above can be deleted. Please do so if you think this is appropriate, or let me know whether you think they should remain; I have no wish to make this lengthy discussion any more tedious that it was originally.

I have made some additions to the main page. These are in two categories - the first is a survey of Weights and Measures Acts (WMA) since 1878. This could be seen as original research, but in the UK such statutes are in the public domain and can be read in public libraries, so they are self-referencing. In my opinion, primary sources must always be preferred over secondary ones, so I urge you to look at these Acts yourself rather than rely on what authors have written about them (including myself). Anyone who is interested may check the accuracy of what I have written; if you find any errors, or can demonstate that I have been selective, that can be corrected. Suppositions of this kind should always be supported by evidence, I feel.

The second category is an attempt to deal with the points made by several contributors in the discussion page. I have done this having read the Wikki guideline which says that after discussion a consensus might be reached. Again, if the resume I have given is felt to be unbalanced, changes can, of course, be made; my intention here has been to include in the main article points mentioned in the discussion, to give them recognition, and to clarify them.

~~~~Andrew Smith

Tower to Troy

Historically the pound sterling was a Tower pound of silver (worth about £144 or about $225 US today). In 1528 the standard was changed to the Troy pound (worth about £60 or $100).

The parentheses are puzzling, given that the Tower pound was smaller than the Troy pound. —Tamfang (talk) 07:16, 11 October 2010 (UTC)

These equivalents in modern currency are dubious, obviously inconsistent with each other, and very volatile. They would normally have to be updated every few months, but this article simply doesn't get enough attention for that to happen. Since nobody seems to be taking proper care of the information and it is already severely out of date, I have simply removed it. Hans Adler 08:13, 11 October 2010 (UTC)

The Offa's tower pound was used for currency for many years after the normam conquest of 1066. According to a table in Woodhouse's "Measures of Weights, Measures and Moneys of all Nations", the troy pound yielded £1 1s 4d up till 1344. This is the same equation as 1 tower pound = £1 currency. The change at 1344 yielded 1 troy lb = £1 1s 6d, but over the following 480 years, this increased to the value in the WMA of 1824: One troy pound = £3 6s. This value lasted until 1946.

Australian 5c, 10c and 20c are still minted at 66s to the troy pound, but are no longer silver. The 50c is minted at 11s to the troy ounce, the original 1966 round one disappeared early, since its silver content was already 47c at issue, and did not take long to pass 50c. --Wendy.krieger (talk) 07:41, 19 February 2011 (UTC)

Tower grains

The Tower pound sections tabulates tower grains as being much lighter than troy grains. Is there any source for the division into tower grains ? I suspect it is a confusion with wheat grains. 1857 Supplement to pharmacopeia shows the tower pound divided into 5460 tower grains (thus the tower grains being 0.98 troy grains). Rod57 (talk) 04:00, 6 March 2011 (UTC)

Move to Pound (mass)

I moved this article to Pound (mass) because.. it talks about mass, not weight. Weight is the same as force, and it is discussed in the Pound-force page. This page should eventually redirect to the Pound-force page, but I don't want to mess up all the pages linking here. Bots anyone? Fresheneesz 01:33, 5 December 2005 (UTC)

♠ The article should have been titled "Pound-mass" (lb_m) for consistency in nomenclature with Pound-force (lb_f). Both are used in engineering and other sciences.--THE FOUNDERS INTENT ^TALK 02:54, 13 December 2007 (UTC)

Ok.. that was reverted. I guess I need supporters. This page is mistitled, anyone want to tell me otherwise? Fresheneesz 05:10, 6 December 2005 (UTC)

• Support because this is indeed about the mass unit and it is important to keep the distinction. Of course it was correct procedure to revert the cut and paste move, but the proper move should be done. Stefán Ingi 00:14, 8 December 2005 (UTC)

• Support, but not because it doesn't talk about weight. It does, but weight and mass are both ambiguous words with more than one meaning, but the ambiguities in the word weight cause more confusion than the ambiguities in the word mass in this context. One problem here is that "pound-weight" and "lb.wt." and the like are old early 20th century terminology for what is now more commonly called the pound-force, which has its own article. Pounds-force were never well-defined before the 20th century, though they had been used in low-precision measurements for a couple of centuries before then. The pounds in this article are units of weight, and have been quite properly called that throughout history—and they were never called units of mass before the last 300 years, because while weight had that meaning long before then, mass did not. Gene Nygaard 16:28, 10 December 2005 (UTC)

Note that in any case, somebody still needs to fix the approximately 400 links to the disambiguation page now at Pound after User:Chaosfeary butchered everything up in his moves. Only a minority of what was originally over 600 of them have been fixed so far. Gene Nygaard 16:45, 10 December 2005 (UTC)

• OPPOSE, article should be at pound (unit) with both pound (mass) and pound (weight) redirecting to it. I was taught in school that a pound is a unit of force, not mass. 132.205.45.148 22:10, 12 December 2005 (UTC)

Comment. So, you were taught badly. You are hardly alone. But leaving it as it is, with the article about the units of mass under pound (weight), isn't going to help you or anyone else. The problem is that the pound-force is a unit (and one sometimes used for things called weight with a different meaning, as well as other kinds of force never called weight such as the thrust of a jet engine), just as the pound at this article is, and so are the units of currency. So using "unit" is even more unnecessarily ambiguous, applying not just to several different units but to different quantities as well. We already have a pound disambiguation page which can lead you to either these units of mass or to the force unit, as well as the units of currency and other meanings. Gene Nygaard 23:56, 12 December 2005 (UTC)

Oppose You were actually the one taught badly from the wikipedia article weight In the physical sciences, weight is the downward force exerted on matter as a result of gravity. An object's weight is equal to its mass multiplied by the magnitude of the gravitational field. That is to say that in terms of actual definition any unit of weight is a force, if you went to the moon your mass would be unchanged but your weight would be less. The should be moved back, or pointed somewhere and the explination that the title with the word weight in it is not technically correct. The redirect it probbly ok but I think the suggestion below redirecting to Pound (unit) and explainning the complications. The way this redirect is, it implies that weight is equvilent to mass which is not at all true. Dalf | Talk 04:02, 24 January 2006 (UTC)

• Clearly support. ナイトスタリオン ✉ 09:23, 20 December 2005 (UTC)

• Support, why is this still up in the air? 2007-07-09 14:39UTC

• Support, A pound is a measurement of weight, which is a type of force (W=mg), and mass in some instances. Should we create a new article for the weight pound? 71.163.132.193 00:16, 31 October 2007 (UTC)

Result

Moved. WhiteNight ^{T | @ | C} 22:49, 28 December 2005 (UTC)

Somebody still needs to clean up after Chaosfeary and that mess of links to the disambiguation page at Pound. Gene Nygaard 02:00, 29 December 2005 (UTC)

Mass versus force

This was mentioned above, but I think it may be worth discussion in the article. The article here describes the pounds as "a unit of mass", but "Density, Specific Weight and Specific Gravity" at The Engineering Toolbox says: "pounds are really a measure of force, not mass. Slugs are the correct measure of mass."

I always thought the pound was a unit of mass, so it surprised me to find that. Could we reach a consensus on this issue, and having done so I wonder whether it is worth covering the confusion in the article. Leevclarke (talk) 02:36, 12 June 2008 (UTC)

According to this source, the idea that the English/US/... pound is not a unit of mass is a common misconception. The source cites various standards bodies and the like, and generally agrees with what I found out about the question. As far as I know, there is currently no country in the world, including the US, that defines the pound as anything but a fixed multiple of the kilogramme, which nobody seems to doubt is a unit of mass. It is also true without any doubt that historically the pound was always defined in terms of physical "weight standards". Sometimes they were exchanged between countries for comparisons, and in those cases they did not make any adjustments for different geographical locations/altitudes, as would have been necessary if it had been a unit of weight in the sense of the definition in physics. I think the misconception comes from the fact that a lot of people who hear about the definition of weight in physics just deny the obvious fact that people outside the field use the word "weight" as a synonym for "mass". I have run into similar problems with some other words, such as "city" (which in a legal context in the UK is not the same as a big town). --Hans Adler (talk) 20:10, 12 June 2008 (UTC)

This still causes lots of confusion, and the article seemed to assume prior knowledge of the distinction, which I think is an unsafe assumption. I added a hook to a discussion of "weight" which appears on the "Mass" page, in the paragraph about the origin of the word "pound". I think this is appropriate (since it explains the origin of the term "pound-mass"). I also think it's a good compromise between cluttering this article with the issue versus ignoring a common question. Digitante (talk) 13:53, 8 September 2009 (UTC)

I've been trying to get my head around the difference between pound mass and pound force, and I'm still confused. Based on information from Wikipedia, I get the following:

(1) lbm=0.45359237kg (http://en.wikipedia.org/wiki/Pound_%28mass%29)

(2) lbf=4.44822162N (http://en.wikipedia.org/wiki/Pound-force)

(3) lbf=lbm x 32.174049 (http://en.wikipedia.org/wiki/Pound-force)

(4) kg=9.80665N (http://en.wikipedia.org/wiki/Newton_%28unit%29)

(5) Rearrange (3): lbm=lbf / 32.174049

(6) Rearrange (4): N=kg / 9.80665

(7) Substitute (6) into (2): lbf=4.44822162 x (kg / 9.80665)

(8) Substitute (7) into (5): lbm=(4.44822162 x (kg / 9.80665)) / 32.174049

(9) Simplifying (8): lbm=0.014098kg

Why doesn't (9) work out the same as (1) ???

Can anyone point out the problem for me? 203.129.23.146 (talk) 05:05, 28 May 2011 (UTC)

Yes, I can; you are mixing units. The conventional symbol for pound-mass is lb, and for pound-force lbf. It is completely incorrect to say 1 lbf = 32 lb, one cannot equate units of force with units of mass, this is the apples and oranges thing. The article you quote actually says 1 lbf = 32 lb.ft/s², units of mass times acceleration, clearly units of force from Newton's second law. One pound-force is the force exerted by one pound-mass under the influence of gravity. Just because gravity happens to be 32 in some system of units does not mean 1 lbf = 32 lb. Let's say we stick with pounds but use some other units to measure acceleration - the metric system say, 9.8 m/s². Do you think that suddenly 1 lbf = 9.8 lb because we have chosen to measure distance and time in different units? No, the amount of mass required to produce 1 lbf remains exactly 1 lb (by definition) regardless of other units. SpinningSpark 08:30, 28 May 2011 (UTC)

It took me some time to write this response, and then I got an edit conflict with Spinningspark. Here is my response anyway: It's a bad idea to do such calculations without using dimensions. Conflating mass and (weight) force is also a bad idea because there is always the danger that you get confused about which of the two you are currently working with. Here is how I would write these equations:

(1) 1 lbm = 0.45359237 kg

(2) 1 lbf = 4.44822162 N

(3) 1 lbf = 1 lbm × 32.174049 ft/s²

(4) 1 kg exerts a force of 9.80665 N

(5) Rearrange (3): 1 lbm = 1 lbf / (32.174049 ft/s²)

(6) Rearrange (4): 1 N is the force exerted by 1 kg / 9.80665

(7) Substitute (6) into (2): 1 lbf is the force exerted by 4.44822162 × (1 kg / 9.80665)

(8) Substitute (7) into (5): 1 lbm = (force exerted by 4.44822162 × (1 kg / 9.80665)) / (32.174049 ft/s²)

(9) Simplifying (8): 1 lbm = 0.014098 s²/ft × (force exerted by a kilogram)

So (9) doesn't work out the same as (1) because it talks about something totally different and should never have been written as an equation. Let's verify (9). By (4), the force exerted by a kilogram is 9.80665 N; also 1 ft = 0.3048 m. So we get

(10) 1 lbm = 0.014098 s²/(0.3048 m) × 9.80665 N = 0.45359 Ns²/m = 0.45359 kg. Hans Adler 08:35, 28 May 2011 (UTC)

A colleague at work has found a mistake. Can't believe I stuffed up the easy bit. I also now understand the consequence of omitting (implied) dimensions of gravitational acceleration.

(3) should be lbf = lbm x 32.174049 x ft / s^2 and (4) should be kg = N / 9.80665 / m x s^2, so...

(1) lbm = 0.45359237 x kg (http://en.wikipedia.org/wiki/Pound_%28mass%29)

(2) lbf = 4.44822162 x N (http://en.wikipedia.org/wiki/Pound-force)

(3) lbf = lbm x 32.174049 (http://en.wikipedia.org/wiki/Pound-force)

(4) kg = N / 9.80665 / m x s^2 (thanks Steve)

(5) Rearrange (3): lbm = lbf x s^2 / 32.174049 / ft

(6) Rearrange (4): N = kg x 9.80665 x m / s^2

(7) Substitute (6) into (2): lbf = 4.44822162 x (kg x 9.80665 x m / s^2) = 4.44822162 x kg x 9.80665 x m / s^2

(8) Substitute (7) into (5): lbm = (4.44822162 x kg x 9.80665 x m / s^2) x s^2 / 32.174049 / ft

(9) Simplifying (8): lbm = 4.44822162 x 9.80665 / 32.174049 x m / ft x kg

(10) ft = 12 x 25.4 / 1000 x m

(11) Substitute (10) into (9): lbm = 4.44822162 x 9.80665 / 32.174049 x m / (12 x 25.4 / 1000 x m) x kg

(12) Simplifying (11): lbm = 4.44822162 x 9.80665 / 32.174049 / 12 / 25.4 x 1000 x kg

(13) Simplifying (12): lbm = 4.448221559 x kg

Not quite there yet. Anyone spot a mistake this time? 203.129.23.146 (talk) 07:47, 31 May 2011 (UTC)

I spent a lot of effort to tell you where your problem is and now you are just ignoring it. If you are not prepared to distinguish the two dimensions force and mass, then you will always be confused. Your change to (4) is not an improvement at all. At first you just confused the two dimensions but it was otherwise correct; now it's just plain wrong. The average acceleration caused by Earth's gravity on the surface is something like 9.80655 m/s². (This precision looks ridiculous to me. Not sure where the number comes from.) You have to multiply this with the mass to get the (weight) force. For 1 kg the force is 1 kg × 9.80655 m/s² = 9.80655 kg m/s² = 9.80655 N.

My version of (9) above tells you precisely what your original problem was. At (at least) 2 points you got confused about the units/dimensions you were working with. As you can see from my (10), my (9) was correct. Hans Adler 07:40, 31 May 2011 (UTC)

Refer edits above (I was apparently working it out at about the same time as you added your comment). Regardless of "correctness", in the real world if I want to convert mass to force I write something like F = 9.81 x mass (the units of gravity are implied). You may have spent effort correcting me before, but as far as I can tell (you will of course correct me if I'm wrong) you still carried through the same mistake I originally made (in equation 4). 203.129.23.146 (talk) 07:56, 31 May 2011 (UTC)

As I explained very clearly (I thought), what you think was an error in (4) was actually correct. Your latest version is worse than the original. F = 9.81 kg m/s² × mass. Your latest version of (4) assumes mass = 9.81 [units???] × F. Your original (9) was off by a factor of 50. By randomly manipulating (4) you got it into the right order of magnitude, i.e. only off by a factor of 2. This kind of trial and error is not a reasonable method for fixing your problem.

At this point I feel compelled to point out WP:NOTFORUM. If you want to discuss this further, please use WP:Reference desk/Science, as your problem is not related to improving the article. Hans Adler 08:09, 31 May 2011 (UTC)

Fair enough, but my point was to prove coherence between the four originally quoted articles as if you look at all their talk pages there is controversy. I thought presenting a set of equations may help settle any dispute. I'll definitely continue my exercise on paper though. Clarity is always subjective, but I nonetheless appreciate your help. 203.129.23.146 (talk) 08:19, 31 May 2011 (UTC)

Equation (3) seems to be contradictory to my original equation (4), because they are sort of reverse sign of each other. I wonder whether I have misinterpreted (3) from the Pound-force article [1], which states "1 lbf=1 lbm x gn". Does that mean 2 lbf=2 lbm x gn (assuming gravity stays the same)? I'd just like to be assured that Wikipedia is correct. This is relevant to the Pounds-force article but is also related to this one and fits with this thread. 203.129.23.146 (talk) 10:08, 31 May 2011 (UTC)

I will respond one more time, but if you have any further questions, please take it to the reference desk.

1 kg = 2.2 lbm (up to rounding). There is nothing wrong with that. The equations at Pound-force are also correct, and of course they stay correct when you multiply both sides by 2.

Originally, instead of writing that 1 kg exerts a force of 9.80665 N (true), you wrote 1 kg = 9.80665 N (false). Then instead of writing that 1 N is the force exerted by 1 kg / 9.80665 (true), you wrote N=kg / 9.80665 (false). The actual equation connecting Newton and kilogram is 1 N = 1 kg m/s², so you were off by a factor of 10 at this point due to your confusion between mass and force. Your new equation (4) is totally wrong. It appears you simply took your incorrect earlier version and added some metric units to fix the dimension. Hans Adler 10:29, 31 May 2011 (UTC)

Thanks again for your response. I'm still confused (1 N = 1 kg m/s² is obvious but not practical in converting anything; its basically just the constituent units of a Newton). I know how to convert between kg and lb and that's all I need in my job so I'll just leave it at that I think. 203.129.23.146 (talk) 10:51, 31 May 2011 (UTC)

After mucking around in a spreadsheet I finally got it. Woohoo! :) 203.129.23.146 (talk) 12:28, 31 May 2011 (UTC)

The thing that confused me was that equations (1) and (2) equate a pound mass with a pound force (on surface of the earth where gravity is 9.80665 m/s²). I think that's why at uni I was taught to use slug and treat lb as a force rather than use lbm. I guess I was taught badly too, but that makes 2 of us (see above). Is anyone else confused by lbm? Can anyone explain things for the rest of us? 203.129.23.146 (talk) 21:52, 31 May 2011 (UTC)

Ok enough - this thread has now gone way beyond discussion of improvements to the article. As Hans said, take it to the reference desk at WP:RD/S. If there are any further posts to this thread I am going to remove it from the page. SpinningSpark 00:06, 1 June 2011 (UTC)

Advice taken, and thanks to everyone for their help. Some interesting answers have come up so far. I've just added this post to point to further discussion. I don't really care if it (or this entire thread) is removed, but I think it would be useful to link to the reference desk discussion. Refer to http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Science#Pound-mass_and_pound-force.3F 203.129.23.146

Tower pound and barley grains

Why has the explanation of barley grains been removed from the Tower pound section? The references directly support this, so it is really for the deleting editor to provide a new ref if this is wrong. SpinningSpark 11:24, 13 February 2011 (UTC)

It's not wrong to remove it, as such, but the impression it carries is that it's a definition, when in practice, the silver penny of Offa is the defining element. This in turn is half a silver dirham.

The pound, like so many of those using 450 troy grains, comes directly from the silver dirham, examples of which are to be found in Offa's Dyke. The link provided is to silver penny which describes a good deal about the relation between the silver dirham and Offa's penny (which is the penny of the pennyweight).

Both Ronald Zupko (English Weights and Measures from Antiquity to the 17C), and A E Berriman (historical metrology) support this. The predominance of the systems of 450 grains (common in the hansa: Prussia used a pound of 466.711 grains [ie the same as the London pound] right up to metrification) and 480 grains (most apothecaries scales lie close to this), suggests that coins, not wheat, is the source of this weight, and that the wheat reference is to assist selecting the coin, not a definition of it.

The austrian and bavarian pounds of 560 grams, are the result of decimalising the hanseatic hundredweight (120 lbs), would also produce pounds of 466.66 grams, when the cwt is correctly divided.

--Wendy.krieger (talk) 07:02, 14 February 2011 (UTC)

So do you think that barley grains could still be mentioned if it was made clear that this was not the basis of the system? SpinningSpark 22:20, 15 February 2011 (UTC)

Yes, it could. One must understand that with ancient definitions, the legal theory does not match the practical implementations. Even something like the troy pound is derived from coin-weights. The measures are too extensively used to be derived from things of nature, and one should look at trade to understand what goes on. See, eg A E Berriman 'Historical Metrology' for the transport of size. --Wendy.krieger (talk) 07:55, 25 April 2011 (UTC)

Pound (mass) should be Pound (weight)

Absolutely, pounds are by nature force. Pounds mass is derived.

I dunno about you guys, but every physical science class I've ever sat through has made the distinction that the pound is a unit of weight and the kilogram is a unit of mass. It's always been very clear-cut for me. If I'm on Earth, I weigh 135 lbs. If I'm on the Moon, I'll weigh 22.4 lbs. If I'm on Earth or the Moon, I'll be 61.4 kg.

So why is this article titled Pound (mass)? It's not a unit of mass, it's a unit of weight. I have never heard differently until now, and I've sat through a lot of science classes... --Lantoka 05:49, 20 April 2006 (UTC)

Please see discussion above, and the section "Force, weight, and mass" in the article. Standards organizations today treat the pound as mass. Engineers and the general public often use the pound as a force (Google the phrase "pounds of thrust", for example). The general public generally does not distinguish between measurements of weight (using a spring scale) and mass (using a balance). High school physics teachers (and textbooks) who use the pound at all (as opposed to the metric system) seem to fall into two camps: those who use the pound as a unit of mass and the poundal or pound-force (lbf) as the unit of force; and those who use the pound as a unit of force and the slug as a unit of mass. Scientists and university physics classes don't really use the pound, so don't have an opinion. Personally, I think it's a bad idea to use the pound as a unit of force, but... by the principle of NPOV, WP should discuss all these uses, making clear which is appropriate when. So the article should probably be "Pound (unit)" and introduce the mass/force issue closer to the top. --Macrakis 14:02, 20 April 2006 (UTC)

The general public maybe doesn't generally distinguish, but the law does, and the usage of manufacturers and government regulators are totally uniform and consistent. The pounds used for "net weight" in selling goods by weight are, and should be, always units of mass, never units of force.

No doubt the law you're referring to is for commerce (governing trade disputes), but regardless, there are also laws regulating aviation, and I can cite one that treats pounds as a force: The U.S. Electronic Code of Federal Regulations (e-CFR) Title 14 (Aeronautics and Space), Subchapter C (Aircraft), PART 23—AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES, Section 23.397 (Limit control forces and torques.) specifies forces in pounds (lbs). Refer http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=17ff3d50f518bbb3a2472296a8435378&rgn=div5&view=text&node=14:1.0.1.3.10&idno=14#14:1.0.1.3.10.3.71.27 203.129.23.146 (talk) 07:33, 5 June 2011 (UTC)

Same goes for human weight, as that is used in the medical sciences and in sports, always units of mass.

The pound-force quite deservedly has its own article. That helps keep the distinction straight; we can link to the correct article. Any mismash which discusses varying units of mass and force in one article would be counter-productive for this usage. Gene Nygaard 18:40, 3 May 2006 (UTC)

I'd support renaming the article to Pound (unit). I can accept that there are other points of view on this issue, but the title of this article just seems a blatant contradiction to me. Pound (unit) should appease everybody and lay the issue to rest once and for all. And it should be done soon, too, since new articles are created every day that link to the pound, and it's gonna be hell to fix all those links... —Lantoka ^{( talk | contrib)} 00:30, 21 April 2006 (UTC)

So, what's your rush? Sure, new articles are created every day. But of all the existing articles which link to either this article ("pound (mass)") or to pound-force, exactly how many can you show us where the link is to the wrong article? Even one? Sure, that's entirely possible. But not 1%, I'll bet. Gene Nygaard 18:45, 3 May 2006 (UTC)

After reading the entire article and talk page, obviously I'm not the first person to have this idea or complaint. This seems like an overly pedantic argument to me. A compromise should be reached so that we can put this issue to rest. What exactly are objections to "Pound (unit)" again? —Lantoka ^{( talk | contrib)} 00:42, 21 April 2006 (UTC)

"Pound (unit)" might work as, but is unnecessary for, renaming of the "Pound" disambiguation page, for the many units of currency as well as several different units of mass and one unit of force. Gene Nygaard 18:28, 3 May 2006 (UTC)

Although I support the "proposed rearrangement" below, as a back up plan I would support "Pound (unit)". Again, what exactly are the objections to "Pound (unit)" again, as asked by Lantoka? The answer given by Gene Nygaard is not only grammatically questionable, but I can't extract any sense from it. "Pound (disambiguation)" should have money and other meanings listed, as well as "Pound (unit)", where the confusion between the classic "weight as a force" and modern "pound defined as 0.454...kg" can be explained. Both "Pound (force)" and "Pound (mass)" would redirect to "Pound (unit)". Go for it. (PS: How many articles link to the wrong "pound"? All of the ones that link to "Pound (mass)" right now, for a start... Imagine clicking on pound of tomatoes and finding yourself reading "the pound is a unit of mass..." -- I thought I'd clicked on the wrong link, until I read further down and realized that what was meant was "pound is a unit of weight"!) --76.11.113.118 (talk) 07:15, 9 December 2008 (UTC)

Mass is the scientific word for weight, while weight is the scientific word for something else (although closely related). For "a pound of tomatoes" this is the right article. – That's where this conflict comes from. I have seen a structurally similar conflict about the word "city" in the past, where someone claimed that a certain settlement in the UK, with a population of almost half a million, must not be called a city because its official city status was transferred to a larger area that is not a settlement. --Hans Adler (talk) 09:54, 9 December 2008 (UTC)

It should be remembered that the ancient measure weight, divides into mass and force, the distinction is only recent. In practice, a pound serves both force and mass roles, both directly from properties of the standard. Force and mass map onto the same scale at the rate of g (eg 9.80665), one even hears of newtons weighing 102 grams.

The notion that Length, Mass and Time are basic units for mechanics, and that there is only one scale for each quantity is clearly wrong. The slug is a derived quantity, measuring W/g, the dimensions being MT²/L. There are many slug-like units (like glug, mug = par = TME, slinch), as well as units like "(lbf s²/ft)-mole" [a unit that appears in the 60th edition of the CRC Handbook of Physics and Chemestry]. The implementation of the gravitational units do not match the implementation of the SI units, and the dimensions likewise do not follow. The slinch is a lbf s² / inch, or 12 slugs is known at NASA, for example.

On the other hand, a pound of pressure, is short for pound per square inch. Unit truncation like this is still rampant today. One of the reasons that 'ampere' was advanced for current, is that 'weber' was used variously for charge (C), and charge per time (A). One still talks of 'k's of speed, that is kilometres (without time units). --Wendy.krieger (talk) 07:54, 19 February 2011 (UTC)

Proposed rearrangement

The pound, as a unit of mass or force, needs just one article: pound (weight). Pound (mass) and pound-force should be redirects to it. This article can discuss the contexts in which a pound means mass, and in which it means force, and so forth. So what do folks think about this? By the way, if you're not sure about the use of the word "weight" to cover all meanings of "pound", see weight. Another reason for this change is that the pound-force article replicates some of the information currently in pound (mass). A combined article would nicely present all relevant information in one article of a sensible length. --Yath 13:59, 15 August 2006 (UTC)

The modern distinction between mass and weight, and its development over time, is discussed in the article on Weight. I do not think the proper place for a discussion of that distinction is in an article on one particular unit of mass or unit of force (even if those units, by reason of their long history, happen today to still share the same name). (I do think the articles on the pound (unit of mass) and pound (unit of force) should contain early pointers to that discussion.) Today and for many decades, the pound has been the name of a unit of mass and, in some specialised circumstances, the name of a (conceptually, quite different although not unrelated) unit of force. I would not support recombining Pound (mass) and Pound-force as it seems that some time and effort has gone into carefully separating them.Fibula 23:41, 17 August 2006 (UTC)

You are imaging a "modern distinction" which does not really exist, though it is indeed a figment of the imagination of many science teachers and the like. "Weight" is never a force, when anybody talks about "net weight", for example--and there are billions of examples of that usage today. Of course, "mass", like "weight", is also an ambiguous word, one with several different meanings, but "net weight" is never different from the meaning of mass common in physics jargon but a minority meaning in the usage of the word mass outside of physics. Gene Nygaard 15:06, 21 September 2006 (UTC)

over exaggerations do little to help your argument. (american) engineers and physicists alike will most likely tell you that "weight" is a force. as a physicist, i define weight as the force created specifically by gravitational attraction. in the category of force comes units of pounds and newtons. for a layperson such as yourself, i can understand the confusion for the need to make a distinction between weight and mass. however, it is a necessary distinction (especially in regards to engineering). just because weight is commonly used to denote mass does not make it accurate. —The preceding unsigned comment was added by 72.85.214.147 (talk) 21:37, 11 March 2007 (UTC).

I am new to this discussion, but have taken the time to read everyone's point of view. My opinion is that there should be just one article for these two units, as one is simply an extension of the other. Whether I'm talking about the force I exert on the Earth or the mass of my body, I am still 150 pounds either way. If both units are on one page, it will be easier to discuss the distinction between them than if they are on separate pages. In short, I agree with Yath. --Lasunncty 20:58, 18 September 2006 (UTC)

I'd very strongly oppose such a rearrangement. We need our links to take people to the proper article. We don't need another disambiguation page, which leaves it up to the people clicking on a link to guess which of the two distinct and separate units is being talked about. Gene Nygaard 14:40, 21 September 2006 (UTC)

I very strongly support a merger. While in metric areas there is a confusion on kilos refering to weight or mass, in the customary units has it own unit of mass, the slug. It is much harder to teach metric raised student that kilograms are strictly mass and Newtons are forces. Because the force of gravity varies little on Earth (from the top of Mt. Everest to bottom of Death Valley), it is customary to use a unit of mass for an amount of force. When "laymen" talk about something "weighing a ton" or "felt like a load of bricks" they are talking about force, not mass. In fact the distinction of mass, as a separate concept from force, only arises in academia where it is important to distinguish them. So the new concept is "mass" not "weight." If anything, kilograms should be clarified instead due to the confusion.

Very strongly support merger. The "parent" class is pounds as a measure of weight, and the units of measure "pounds force" and "pounds mass" are variants on that unit of measure. I came here looking for the definition of the unit of weight; and visited the other article first, as that was the most logical course for me to take. (I found what I was looking for, but got caught up in this highly engaging discussion!) --Rfsmit (talk) 21:49, 6 October 2008 (UTC)

I also very strongly support the merger for the reasons listed above. Additionally, I disagree that most articles mentioning pound refer to pound as mass as has been previously suggested. Traditionally the unit pound is used as the measurable quantity pound. There is no direct way to measure mass unless you can count all of the atoms in a substance and know exactly what each of those atoms are. The directly measurable quantity (and therefore the meaning that most people intend) is weight (which is a force). Practically, in most applications mass can only be arrived at by means of measuring an object's weight. Considering that mass is a more "scientific" concept, and also considering that in most scientific applications pounds are not even used as a unit of mass, I believe that pound (mass) should just be a note in the main article. I understand the volition of some people who would like to be as accurate as possible, creating separate pages. However, I think that this can also contradict common sense, especially in this case. Contradicting common sense will, I believe, only cause confusion among readers. Jrobinjapan (talk) 06:36, 29 October 2008 (UTC)

Note: I believe the current separation of the pages also leads to confusion for editors when trying to decide which article to link to, with many pages linking to the disambiguation page instead. Then you have to look through the whole list of articles to try to find the one you are looking for, only to discover that there are two articles and you aren't sure yourself which one to click on. Jrobinjapan (talk) 06:58, 29 October 2008 (UTC)

I strongly support merger. My only reservation is that the Pound-force article actually gets it right, and it would be shame to suck it into the morass of junk on this page. It's surprising how many people on this talk page insist that the pound is a unit of mass, trying to prove it with circular arguments claiming there are millions of examples of uses of it like this, none explicitly mentioned, but from the general examples (supermarkets) they are quite clearly weight measured as force due to gravity. Gene Nygaard in particular makes some good points but then makes bizarre statements like that it's "not true that kilograms are "undeniably units of mass, not weight"", backing that up with nothing but the that the concept of 'kilogram-force' once existed. Listen. Governments may define the pound as a fraction of a kilogram, but that does not make the world use mass for trade and commerce. The people in the US use weight in pounds, a measure of force due to gravity, to weigh virtually all goods "sold by weight". Goods are also sold by volume, but never by mass. In the rest of the world, goods are sold in grams, a unit of mass, even though they were almost certainly weighed out on a scale, not massed on a balance. But on another planet you could still purchase the same quantity if ordered in grams, although scales intended for Earth use, even if they claimed to measure in grams, would be wrong. As countless people have pointed out, we teach our kids in school that we "weigh" a different number of pounds when gravitational force changes, such as on another planet. So. That the pound is used as though it were a unit of mass does not make it one, any more than that the kg is used on scales as though it were unit of force does not make the kg a unit of force. The pound has always been a unit of weight, that is a force. While often used as a synonym for, equated with, or considered equivalent to mass, that does not make it the same as mass. Pound is also used for non-mass related forces, such as the pull on a rope, or pounds per square inch of air pressure. Note that in the metric system we do not use kg/cm², as this is nonsensical; we have a pressure unit (pascals) instead. Similarly it is nonsensical to insist that the pound commonly represents mass. Even if it is commonly, in modern times, defined in terms of kilograms. I will go away now and let my comments be ignored with all the rest, and the Pound page will remain a disaster of mixed units. But please, would somebody rational change the page in a sensible way (describing the confusion and and the rarely used pound-mass unit for completeness) and then somehow lock the page? It seems that despite all the reasoned points laid out here by many people, all too often someone comes along and has the bright idea (duh) to just change Pound to refer to mass again, <sigh> --76.11.113.118 (talk) 06:55, 9 December 2008 (UTC)

I support a merger. The title of the article could be "Pound (imperial unit of weight)" or something of the sort. There is ambiguity and dispute about it and someone looking for the definition of the generic "pound" as an imperial weight/force/mass/whatever should be presented with all relevent info (without the politics/religion/heresay/supermarket analogies). One of the problems I've observed with arguments in these talk pages is that rarely do comparisons get made beyond Earth gravity, so its easy to argue either way. There are also various systems (such as FPS engineering and FPS gravitational) that aren't mentioned at Pound (mass) but are at Pound-force. Slugs is also clearly worth mentioning, but it must be correct. The Slug (mass) article contradicts itself. Lets just lay it out on a single page and let the battle begin :) 203.129.23.146 (talk) 06:47, 5 June 2011 (UTC)

Proposed WikiProject

Right now the content related to the various articles relating to measurement seems to be rather indifferently handled. This is not good, because at least 45 or so are of a great deal of importance to Wikipedia, and are even regarded as Vital articles. On that basis, I am proposing a new project at Wikipedia:WikiProject Council/Proposals#Measurement to work with these articles, and the others that relate to the concepts of measurement. Any and all input in the proposed project, including indications of willingness to contribute to its work, would be greatly appreciated. Thank you for your attention. John Carter 21:08, 2 May 2007 (UTC)

These articles still have questionable integrity in 2011. 203.129.23.146 (talk) 06:37, 5 June 2011 (UTC)

Pounds and slugs

PatrickandBrenda, I have reverted your changes because your definition of slug (mass) is incorrect. Here are the facts, very simply:

• The force required to accelerate 1 slug at 1 ft/sec² is 1 pound-force. A slug is another name for a lb•ft/sec².
• The force required to accelerate 1 slug at 32 ft/sec² (the acceleration of Earth's gravity) is 32 pounds-force: a slug weighs about 32 pounds-force on the surface of the Earth.

The changes you keep making to the intro get this wrong by a factor of 32. The section on Commerce may be fine, though it seems to be mostly copy-pasted. I have simply been reverting to the most recent error-free version.

A second point is that your reference to the universal gravitational constant, G, is incorrect. What you mean is Earth's gravity, g.

Thanks for your work on the article. Please consider these comments, and look up the definition of a slug before adding slugs back into the intro. Rracecarr 21:13, 20 August 2007 (UTC)

Since pound-mass and slugs are both units of mass, what is the conversion factor between the two? (Maybe it's necessary to assume we're on earth?) Renduy (talk) 17:02, 6 May 2011 (UTC)

Is the answer not in Slug (mass)? SpinningSpark 17:46, 6 May 2011 (UTC)

It would make sense to me to have the conversion of any one thing to another in both articles (with the subject reversed). Conversion between slugs and pounds (mass) would be as relevant in Pound (mass) as in Slug (mass). 203.129.23.146 (talk) 06:32, 5 June 2011 (UTC)

Default "lb" - is it force or mass?

I see a buncha arguments about how pound is defined, as a unit of force or as a unit of mass. I happened to have learned it as a derived unit of force, defined (derived) as the force that accelerates 1 Slug at 1 ft/sec2. All very neat when one first learned the MKS system which has mass (and length and time) as the fundamental units. It is a simple matter of replacing the Kg with the Slug and the meter with the foot. Viola! Simple! That bastard unit, the ugly "pound-mass", is for people who don't really understand. It's also used for a few bad-old engineering traditions - like that awful "Specific Impulse" being expressed in "seconds" by canceling lbf with lbm for crying out loud! - lbf/(lbm/sec) = "seconds"?! (WTF?!). Anyway, lbm is really mostly just an annoyance promulgated by the ignorant, IMHO (big smiley).

But, what really matters is the current way it is defined by the real standards organizations, right? - not how it is explained by some internet engineering toolbox. My question is: "If we write "lb" or "pound" without other clarifying context, does it mean force or mass?" In the whole of my 30 year engineering career, it's meant force and that's how I've made (small) edits. BUT! It could very well actually mean mass IF it is defined that way by the big standards organizations (not by some web page). It could also very well be defined as both, again by the big standards guys. I went with force. If we want to switch it to mass or both, I think we need to cite it well with that really good reference from those big standards orgs.

108.7.241.145 (talk) 18:51, 14 January 2011 (UTC)

The pound is, and always was, a unit of mass. When it became clear that one must distinguish between mass and weight, the unfortunate choice was made of referring to the more fundamental notion of mass with a new word and reserve the traditional word weight for the force. This renaming was not universally followed. In common parlance, mass is still referred to as "weight", and this has led to a number of common misconceptions.

When countries exchanged physical pound standards in order to harmonise their standards, they never made corrections for the slight differences in gravitational acceleration. Scales that measure pounds are not calibrated differently according to the height in which you intend to use them. (At least not in the straightforward way you would expect if they were measuring a force.) One thing that may contribute to the confusion is that the NIST is referring to the physical things that you can use to calibrate scales as "weights" (while making it totally clear that their mass is what they are about).

The following is from NIST Handbook 44, Appendix B:

The primary standard of mass for this country is United States Prototype Kilogram 20, which is a platinum-iridium cylinder kept at NIST. We know the value of this mass standard in terms of the International Prototype Kilogram, a platinum-iridium standard which is kept at the International Bureau of Weights and Measures.

In Colonial Times [...]

The avoirdupois pound is defined in terms of the kilogram by the relation:

1 avoirdupois pound = 0.453 592 37 kilogram.2

These changes in definition have not made any appreciable change in the value of the pound.

[...]

The mass of a body is a measure of its inertial property or how much matter it contains. The weight of a body is a measure of the force exerted on it by gravity or the force needed to support it. Gravity on earth gives a body a downward acceleration of about 9.8 m/s2. (In common parlance, weight is often used as a synonym for mass in weights and measures.) The incorrect use of weight in place of mass should be phased out, and the term mass used when mass is meant.

Appendix C discusses "pounds (lb)" under "Avoirdupois Units of Mass", but does not discuss any units of force at all.

I believe NIST is the only relevant standards organisation in this context, since the other two non-metricated countries (Liberia and Myanmar) hardly count. The UK is already sufficiently metricated that we can probably ignore it as well, but in case you are interested, its Weights and Measures Acts define the pound as a unit of mass and do not mention force.

Any merchant selling you a pound of some expensive good and then handing you over less than a pound in mass on the grounds that the local gravitational constant is unusually large would be committing fraud. As far as I know there is no standardised gravitational constant for legal purposes. Every bit of packaging telling you that the contents is so and so many pounds or ounces (lb and oz) is proof that these units are legally units of mass. Hans Adler 19:29, 14 January 2011 (UTC)

The British Weights and Measures Act 1985 defines a "mass or a weight" of one pound to be 0.45359237 kilograms, but then our Parliament is full of politicians, not scientists. I am updating the article to reflect this. Martinvl (talk) 20:28, 14 January 2011 (UTC)

From Weights and Measures Act, "A Weights and Measures Act is an Act of Parliament determining trade law where the weight or size of the goods being traded are important", so the purpose of such an Act is to settle trade disputes, not govern science and engineering. Are all units of weight and measure covered in such an Act? If so it would have credibility in the scientific community, but if it only defines units commonly used in goods trading then I would argue that it is should be mentioned at Pound (mass) out of interest, but that it shouldn't govern the entire article. 203.129.23.146 (talk) 06:05, 5 June 2011 (UTC)

historical definitions

you should divide this page in histroically used pounds and pounds active today. --Philtime (talk) 18:56, 16 March 2008 (UTC)

There are no pounds legally in use today (except for the USA, and various unofficial usages, as described in the article.). TiffaF (talk) 10:56, 8 September 2008 (UTC)

Ahhh.... yes there are...

"Subject to subsection (6) below, the yard or the metre shall be the unit of measurement of length and the pound or the kilogram shall be the unit of measurement of mass by reference to which any measurement involving a measurement of length or mass shall be made in the United Kingdom; and—

(a)the yard shall be 0.9144 metre exactly;

(b)the pound shall be 0.453 592 37 kilogram exactly."

UK Weights and Measures Act, 1985, Section 1

David 161.51.11.2 (talk) 16:33, 10 February 2011 (UTC)

The "pound" as a force is used as part of the "FPS engineering" system of units (with "slug" as corresponding unit of mass) by aeronautical engineers around the world. By "pound" I do not mean "pound-force", which is part of the "FPS gravitational" system of units, an incoherent system of units of little use to engineering. The two systems are likely a common source of dispute because a "pound" in the FPS engineering system of units is the same as a "pound-force" of the FPS gravitational system of units on the surface of the Earth, resulting in the same conversion from metric for both. In the aviation industry, trade laws don't take precedence over aviation regulations (even in the UK), so while citing a law is valid, it must be kept in context. 203.129.23.146 (talk) 23:19, 10 June 2011 (UTC)

Definition section

Spinningspark in this edit removed the words "of force" and explained in the edit summary "afaik there are no historical definitions of pound as a force until the modern pound-force". I reverted for several reasons:

• There is no clear dividing line about how old a definition, explicit or implicit, must be if it is to be considered historical. Certainly engineers have used the pound as a unit of force for a long time. I don't have any citations handy, but Klein in The Science of Measurement: A Historical Survey (p. 338) indicates that James Watt used the pound as a unit of force.
• The distinction between weight (that is, the gravitational force exerted between the Earth and an object) and mass was not understood until Newton came up with his laws, so before that, we can argue that the pound was used indiscriminately as a unit of force and mass.

Jc3s5h (talk) 00:51, 12 February 2011 (UTC)

I am not, of course, disputing that pound-force is a unit of force which has been in use for a very long time. What I am disputing is that there has ever been a pound that is defined as a force, other than the derived unit definition of "the force exerted by a pound weight". The claim of force occurs in the introductory section of the definitions section (without citation) and yet none of the pound definitions that follow are actually definitions of force. They are all definitions of mass, the widespread and historical use of the term weight notwithstanding. This is quite similar to the useage of Kelvin as a unit of energy in particle physics: no one would argue (at least its Wikipedia article doesn't) that the Kelvin is defined as a unit of energy. For this to stay, at the very least, citations are needed to examples of pound defined as a force. SpinningSpark 10:23, 12 February 2011 (UTC)

OK, how about this quote from Haliday & Resnick, Fundamentals of Physics (revised printing, 1974), Wiley, p. 68:

In the British engineering system of units, however, force, length, and time are chosen as the fundamental quantities and mass is a derived quantity. In this system mas is determined from the relation m = F/a. The standard and unit of force in this system is the pound.

Certainly some of our younger readers will regard a book from 1974 as historical. Jc3s5h (talk) 13:59, 12 February 2011 (UTC)

I cannot access that book to see the full text, but this unit is more commonly called pound-force as described above and the unit of mass would be the slug in this system. Halliday & Resnick are in the minority in calling this simply pound without qualification (if indeed there is not a qualification in the following text). SpinningSpark 17:51, 12 February 2011 (UTC)

Since I used the book in my university physics course, I can assure you it uses just "pound" as a unit of force throughout. Also, any use of the term "pound per square inch" is implicitly defining the pound as a unit of force. As long as there is substantial use of "pound" as a unit of force I think the mention of it as a unit of force should stay, even if the use is a minority. Jc3s5h (talk) 00:58, 13 February 2011 (UTC)

As an engineer I have never used either the FPS gravitational or absolute systems of units before (see table @ Pound-force under section titled "Foot-pound-second systems of units"). I have only ever used the FPS engineering units, with slug as the unit of mass and pound as the unit of force. I have never used "pound-force" in the context of the FPS gravitational system (with "pound-mass" as corresponding unit of mass) because it is an incoherent system that doesn't agree with Newton's second law (refer to note under table). If a system of units doesn't play nice with Newton's second law, I can only wonder what other laws of physics it may violate, which doesn't make it of much use as a system of units in engineering. The FPS engineering (slug, pound) and metric (kg, Newton) systems are what engineers use. If you ever hear an engineer tell you he uses "pound-force", it means that he uses the FPS engineering system of units and he has never heard of the convoluted FPS gravitational system of units (and why would he have if its useless to him) and is simply refering to a pound as a force. It would seem that we must be pedantic regarding terminology on a page like this where confusion can be created by (even accidental) misuse of the word "pound", as it clearly has different meaning in different FPS systems of units. 203.129.23.146 (talk) 22:48, 10 June 2011 (UTC) Refactored to here Gerardw (talk) 00:22, 11 June 2011 (UTC)

Automatic archiving

This talk page is getting rather long. If there are no strong objections, I would like to set up automatic archiving with a search function for the archive. Hans Adler 08:10, 1 June 2011 (UTC)

I agree that it should be archived, but I don't like to see slow moving pages (it has taken six years to get this long) automatically archived. Editors who only visit here rarely will not get a chance to reply. If it is archived now, it is going to be another six years before it needs doing again, which is not particularly onerous. SpinningSpark 09:01, 1 June 2011 (UTC)

Well, I was thinking of automatically archiving each thread after 12 months without activity, or something like that. The big advantage of starting with automatic archiving is that everything is in place in case the page suddenly gets more busy, as might well happen here if someone decides to improve the article. Converting manual archiving to automatic archiving is more work. Hans Adler 09:27, 1 June 2011 (UTC)

Twelve months seems like a decent wait time for a page a slow as this. JIMp _talk·cont 10:33, 1 June 2011 (UTC)

Automatic archiving is really handy for very busy pages but it does have a serious disadvantage: the page history is now on a different page from the archive. On the other hand archiving by moving the entire page to an archive will move the history with it. The argument that the page might get busier in the future applies to any page, but we don't autoarchive all pages. Setting up autoarchiving some time in the future is no more work than it is to set it up now. SpinningSpark 07:58, 2 June 2011 (UTC)

Finally a clear explanation of the pound-mass / pound-force matter in a reliable source

The following excerpt is from Cardarelli, François (2003), "The Foot-Pound-Second (FPS) System", Encyclopaedia of Scientific Units, Weights and Measures : Their SI Equivalences and Origins, Springer, pp. 51–55, ISBN 9781852336820.

In parallel with the development of the cgs system [...] came what was seen as its imperial equivalent, the foot-pound-second system, proposed by W. Stroud in 1880 and sometimes called the Stroud system in commemoration. It became very widely employed in all branches of engineering, and most technical papers written in Britain, the USA, and other parts of the English-speaking world before about 1960 would have used these units, although scientific papers tended to use cgs units.

[...]
Its main problem was that the pound had long been in common use as a unit of both weight and mass. This makes no difference in general and commercial usage, since, because of Earth's gravity, a mass of one pound weighs exactly one pound. [Example: taking a fixed mass to the moon reduces its weight to a sixth.] Weight, therefore, is the force with which a mass is attracted by gravity, and, since it is an entirely different quantity, it requires a different unit.
Force was defined by Newton as mass × acceleration. In a coherent system of units, any derived unit must interrelate one-to-one with the system's base units, so that one force unit equals one mass unit times one acceleration unit. In the FPS system, with the pound as the unit of mass, one force unit is required to impart one acceleration unit (1 ft.s^-2) to a mass of one pound. The acceleration due to gravity is approximately 32 ft.s^-2, so that weight of one pound mass is in fact equal to 32 force units, and the force units must therefore be 1/32 pounds [more precision in parentheses]. This is termed the poundal.
However, because in general use the pound had always been appreciated as a unit of weight, there was a tendency among engineers to continue to use it in this way. In a variant of the FPS system, usually termed technical, gravitational or engineers' units, the pound-force (lbf) was taken as a base unit, and a unit of mass was derived from it by a reversal of the above considerations. This unit was named the slug, and was the mass which when acted upon by one pound-force experienced an acceleration of 1 ft.s^-2, so was equal to 32.17 lb. This version of the FPS system was more commonly used in the United States than anywhere else.
The FPS system was never made fully coherent by the incorporation of electrical or molar units. It did however have derived units which were for the most part expressed clearly in terms of their base units and not given separate names as in the SI. It is true that in practice they were often abbreviated (e.g. psi for lbf.in^-2), and that they were often used in a non-standard way, or in a way that confused the two subsystems. The example just quoted shows this quite clearly: the 'p' is intended to mean 'pounds-force', the abbreviation should be written lbf.in^-2, and the correct FPS pressure unit should have been poundals per square foot (pdl.ft^-2). In fact, the pound-force and pound-weight were often used quite indiscriminately, with the acceleration due to gravity, 'g', being used so commonly as a correction factor that it was humorously referred to as the 'engineers' constant'.
[More on specific derived units.]

With its various inconsistencies, inherent and imposed, and with the increasing internationalization of the metric system culminating in the creation of the SI, it was inevitable that the FPS system would become obsolete. Yet, in concluding this brief survey of the FPS system, it is worth noting that there was nothing inherently inconsistent in a system based on the foot and the pound in themselves. Decimalized, with a single set of force and mass units, and integrated with electrical and molar quantities, it could have been just as consistent and international as the metric-based SI. [...]

Hans Adler 09:54, 5 June 2011 (UTC)

Are you going to put this in the article, or do you just like blowing smoke out your bum? 203.129.23.146 (talk) 10:05, 5 June 2011 (UTC)

PLONK. – Long version: You have nagged me to the point where I finally found the solution to this long-standing problem. Thank you for that. But your latest reaction is totally unacceptable, and I will simply revert any further WP:TALK violations by you. Hans Adler 11:05, 5 June 2011 (UTC)

It is interesting that its "main problem", to quote the above citation, is also a problem for the metric system. It is quite common to measure pressure in metric countries in kilograms per square centimeter. Rwflammang (talk) 08:59, 10 July 2011 (UTC)

I have never seen kilograms per unit area used in reference to pressure. I have seen it only as a mass per unit area, and it is multiplied by 'g' (~9.81 kgm/s2) to determine a pressure in Newtons per unit area.

WikiDMc (talk) 13:03, 10 July 2011 (UTC)

This whole thing seems rather adorable, in that it appears that a great many people who don't actually use pounds in engineering calculations argue about what it really means. Civil engineering in the United States is probably far and away the largest user of the US Customary system, and we use pounds (where "pounds" by itself is a unit of force) and kips (kilopounds, or 1000 pounds) for force, and slugs for mass. I have never seen variation from this, and it confuses precisely nobody. Occasionally, you see somebody who feels a burning need to write "lbf" to be absolutely precise, but nobody will see "lb" by itself confuse it for mass. Building codes specify pounds or kips for loads and moments--ASCE 7 and the AISC steel code are examples, but you can dig up others. You convert beween a mass of slugs and a weight in pounds with g=32.2 ft/s, exactly analogous to converting between weight in Newtons and mass in kilograms. CatCube (talk) —Preceding undated comment added 03:40, 8 September 2011 (UTC).

The last editor wrote "... and it confuses precisely nobody". Possibly US civil engineers are not confused, but they do not constitute all of humanity. The purpose of an encyclopeadia is to make this knowledge availalbe to everybody, not just US civil engineers. Martinvl (talk) 06:26, 8 September 2011 (UTC)

The problem is the way the articles on the pound are structured. There's a separate article for pound-force, as if that's off in the corner by itself. As long as they are treated separately, rather than together as in Pound (unit) with an explanation for how people use pounds, pounds-mass, and slugs, it will be confusing. And, to be honest with you, the articles look like they were written by somebody who was vaguely angry that people dare to use something other than SI, and that they need to be worded as confusingly as possible to show people how stupid it is to use them. The NIST standard being waved around above details a use of the pound that nobody in technical professions uses, because it's stupid and confusing, and would require carrying acceleration due to gravity throughout calculations. Nobody who cares about the distinction between mass and weight and actually uses the US Customary system on a daily basis uses pounds as mass for this reason. You see this in engineering textbooks, where the author will throw a sop to the "official" definition from the NIST standard (though they never actually reference it) with pound-mass also being possible, then they promptly forget about that crap on the next page and continue on using pound as a force. Sure, it may be defined that way for commerce, but since we're not buying our bananas on the moon, the distinction is irrelevant, and the lbf/lbm thing doesn't matter. The way they are mashed together is similar to how English is inconsistent in how it conjugates verbs or has irregular plurals (like mouse/mice). If you just use the US Customary system for what it is--a tool to communicate numerical information--and be consistent with it, there is very little confusion. If you get wrapped around the axle about how it's not philosophically perfect, you'll wander off into nowhere. CatCube (talk) 18:21, 8 September 2011 (UTC)

While US engineers may generally use the pound as a unit of weight only, the large majority of the US population use the pound almost exclusively for measuring quantities of food or flesh, i.e. as a unit of mass. The extensive quotation above refers to these two uses as two variants of the FPS system. Personally I agree that it would be best to merge pound (mass) and pound-force into a single article pound. There is an unfortunate tendency to keep information on closely related topics in separate articles just because some kind of distinction can be made, and sometimes it's hard to correct that. However, as long as the two articles exist we will have to take a decision to present primarily the US engineering point of view, the NIST and general population point of view, or both. In my opinion it is best to present both, but to start with the NIST / common language POV and describe the other as a variant.

The strong feelings by some engineers from the US are just one example of what I keep seeing on Wikipedia: When people have to spend a lot of effort to accept something that is counterintuitive or a minority use (other examples include religious dogmas and putting commas inside quotation marks even if they are not part of the quotation), they tend to turn into missionaries. But the strong feelings of engineers are not sufficient reason to make the pound articles harder to understand for non-engineers by giving this minority usage equal validity. Hans Adler 22:54, 8 September 2011 (UTC)

If you want to be technical, they rarely actually measure mass in commerce (or anywhere). Most practical scales nowadays use a load cell, which relates the gravitational force exerted on the scale plate to an electrical resistance, so you're technically buying by weight. It's just that the variances in g are so small that the mass is correlated to the weight to a degree acceptable for use in commerce. But they never determined that there were 500 grams of product in that cake mix, they determined that the product weighed 4.91 Newtons and slapped 500 g on the box. You could just as correctly write "NET WT. 1.10 lb(f)/4.91 N" on the packaging for as much care as goes into determining quantities. Hence my statement"...nobody who cares about the difference between weight and mass...." And your statement of "spend a lot of effort to understand something" is actually why many users of the system get frustrated--it's easier to understand than this article makes it. The problem is finding a source for the proposition that there are philosophical inconsistencies in unit names, due to the system's evolution prior to the knowlege of the distinction, and that the use of the system in practice has evolved to cover for those inconsistencies. Having the pound force off in another article increases confusion, it doesn't decrease it. CatCube (talk) 02:44, 10 September 2011 (UTC)

ETA: And you're on the right track with putting both uses in the article, and wrong about waving the engineering uses away as "minority" It is minority, but the vast, vast majority of buildings in the largest economy in the world are designed using the system, so I don't know that it increases anybody's understanding to paper over a rather important use. CatCube (talk) 02:47, 10 September 2011 (UTC)

You are splitting hairs. It doesn't matter which proxy the usual scales are using in order to determine mass. If you set up some elaborate scam involving a centrifuge in which you sell expensive stuff by weight rather than mass so it's less, I am sure a judge is going to explain to you precisely why you are wrong. And failure to understand the judge's point is not going to help you. Hans Adler 17:36, 10 September 2011 (UTC)

Well, you'll have to forgive me for doing so, seeing as this entire talk page is an exercise in hair-splitting. Pounds (without qualification) are used as both units of mass and force, depending upon who you're talking to. The NIST definition (lbm, 453.3g) is used in commerce. I have no idea what they use for force, but it doesn't matter much since the weight/mass distinction is irrelevant, since practical commercial operations assume standard gravity. Civil engineers (and from what I've seen, mechanical and aeronautical engineers, but I don't have first-hand knowledge as to their standard practice), always use pound as a unit of force equivalent to 4.45 N, and uses of pound-mass are vanishingly rare, usually just long enough to convert them into slugs. This is because we have to use Newton's second law, and don't care to carry g throughout to satisfy some definition in commerce that was likely implemented without fully considering the implications for scientific work. According to Wikipedia (the three most trusted words in information!) there is a system that uses pound-mass with a unit called poundals for force, but I've never seen this, and one of your links above indicates that this may have been historical British practice. If you want to get technical with legal definitions, then laws in the US have both lbm and lbf for the pound--the commercial definition from the NIST standard for the lbm, while most building codes use the pound as a unit of force, but they have it by incorporating model codes from civil engineering organizations by reference (ASCE 7 is probably the most prominent of these).

None of these uses are wrong, they're just different. As I said, the uses have evolved over time, and have become standard for their respective areas. And users will jack around with these to satisfy some perceived need: most survey work is done along roads with the 100-foot station, and decimal fractions of a foot. Structural engineering commonly uses the kilopound (or kip) of 1000 pounds, rather than the ton, for force, simply because it was easier to avoid the factor of 2 before the death of the slide rule. It remains out of tradition.

And these should be captured in the Wikipedia article on the pound. Here's some food for thought: the American Association of State Highway Transportation Officials (AASHTO) publishes design specifications for roads in the United States that are usually incorporated by the states as legal codes. To quote from the FAQ on their website about the LRFD specification for bridges,(https://bookstore.transportation.org/faq.aspx?#28) "...The fourth edition (2007) was the last to contain an SI units volume. Starting with the 2008 interim, all editions and interims are published in U.S. units only." Cry all you want about how wrong you think these uses are, they aren't going away anytime soon, and having Wikipedia ignore them will greatly reduce the utility of the article. CatCube (talk) 22:20, 10 September 2011 (UTC) Edited 22:22Z to fix a mistaken use of the word "mass" instead of "force." CatCube (talk) 22:23, 10 September 2011 (UTC)

And, to be honest with you, [both] articles look like they were written by somebody who was vaguely angry that people dare to use something other than SI, and that they need to be worded as confusingly as possible to show people how stupid it is to use them. Excellent! CatCube sure managed to peg the teeny boppers who write these "weight-mass" articles. This sort of evangelism is grotesquely un-encyclopdic. Rwflammang (talk) 23:49, 8 September 2011 (UTC)

Would you like to become constructive and give precise pointers to aspects of the article(s) that you feel are not neutral, and reliable sources that can be used for better neutrality? Hans Adler 17:38, 10 September 2011 (UTC)

In most of the US, in most professions, the "pound" is used as a unit of force and as a unit of mass. What is meant is either clear from context or, frequently, not an important distinction. Here's an RS: "The word pound is used for the unit of both force and mass and consequently is ambiguous." {{cite book |title= Marks' Standard Handbook for Mechanical Engineers|last= Avallone|first=Eugene A.|coauthors= Theodore Baumeister III |year= 1986|publisher=McGraw-Hill |location= New York|isbn= 0-07-004127-X|page=1-25 }}Gerardw (talk) 12:25, 11 September 2011 (UTC)

Are you including medical professions and professions that have to do with buying or selling products by "weight" (= mass) in your count for "most professions"? Are you weighting professions by how many people have to do with them?

Of course "pound" is ambiguous, and of course the distinction often does not matter. But it appears to me that the experts on standardisation who are in charge of getting order into this mostly got it right by defining the pound primarily as a precise multiple of the kilogramme, while many (not all) engineers get it wrong.

A NIST document which says that the pound is precisely 0.45359237 kg implicitly sets its context as outside the special customs of engineers who are primarily interested in statics. But similarly an engineering textbook claiming that the pound is a unit of weight rather than mass is only correct when read in its context. The NIST context, which is authoritative for contexts such as trade and medicine, is clearly more appropriate as the starting point in a general-purpose encyclopedia than the practices of a set of closely related technical professions, which mislead people into believing that the physical weight standards which have historically defined the pound were meant as standards of force rather than quantity (obviously false, as nobody ever made corrections for different gravity when moving them), or that there is something weird about the fact that since 1893 the pound has been defined in the US in terms of the kilogramme, making the pound-force a derived unit. Hans Adler 13:48, 11 September 2011 (UTC)

The reference is not a textbook, its a reference handbook. Can you provide evidence of NIST "authoritativeness"? Has there been disciplinary action taken against an MD for calling a pound a force??? Do you have evidence of buildings failing down or equivalent because engineers are "getting it wrong"? Units are arbitrary, and using a system where the a in F = ma is 1 makes things a lot simpler, which is why the its the generally used US system.

Reviewing the history of this talk page, the time averaged consensus is it's both mass and force, and that's how it is used. A general purpose encyclopedia should described things as they are. Gerardw (talk) 14:14, 11 September 2011 (UTC)

It's both, but historically and in common usage it's clearly primarily a unit of mass. That's obvious because it has always been defined in terms of a standard that has a well defined mass but not a well defined (weight) force. Spring scales are calibrated so that they give the right mass readings at a default location. For use in unusual places, they must be recalibrated on location, using standardised weight pieces (= pieces of a defined mass). For balance scales this is not necessary as they only compare weight to that of the weight pieces, so the local gravity doesn't matter (so long as it doesn't get too tiny and doesn't break the scales).

Units are arbitrary, but you can make their interplay easy or complicated. Your F=ma or F=m argument only makes sense when you are specifically interested in statics, and even then it only makes sense for statics under standard condition (near the Earth surface). Not only is this argument irrelevant, but you also pay for this supposed simplification by getting a confusing factor into Newton's second law, a much more fundamental law that should not contain any geocentric constants. Hans Adler 16:10, 11 September 2011 (UTC)

Well, historically, it the pound wasn't really either mass or force, since it predated the knowledge that there was a difference between the two, and as far as "common usage" goes, if you stopped 100 random people on the street, you'd be lucky if 10 knew that there was a distinction between mass and force, and many of those who do probably had a physics class very recently. For the average person, the mass/weight implications of Newton's second law is minor trivia, and most people don't bother to remember trivia that doesn't bear directly on their work or interests.

And, this is important, you do not have a "confusing factor" in Newton's laws with the pound as used by technical personnel--if you use the pound as force, and measure mass in slugs, the system works exactly like SI, just with numbers of different magnitude. If we used it as you insist is the only "right" way, there would be a "confusing factor", which is why we don't do it. We use a system that makes "their interplay easy". This needs to be in the article, because the article is for lay personnel. Technical personnel are not using Wikipedia to figure out the conventions of communicating within their profession (or I hope they aren't) and those who use the system every day will not be confused, because convention in technical practice is to use pounds as a force. However, a lay reader who is trying to search for information to aid his or her understanding of, say, a journal article or a building code that assumes "lb" means pound-force will not find this Wiki article useful, because it totally ignores the system as used in technical practice.

The article should give the "official" definition primacy, but it should not ignore other significant uses. Wikipedia should state things as they are, and the use of the pound as unit of force is a significant use. CatCube (talk) 17:38, 11 September 2011 (UTC)

Mostly agree. In some (many) engineering fields, pounds is also used a mass. Again there is no confusion because what is meant is clear from context. Gerardw (talk) 18:03, 11 September 2011 (UTC)

Of course the pound as force is a significant use and needs to be discussed somewhere, as it is. But it must be made clear that it's a specialist use, and it's not exactly on-topic in an article whose title is "pound (mass)". Besides, this article doesn't just discuss the avoirdupois pound, but also the notion of a pound in general and many of its incarnation. If there are any others among them that have ever been used as a unit of force, then that would also be worth mentioning, but I am not aware of that and I am pretty sure that it's a tiny minority. Hans Adler 20:32, 11 September 2011 (UTC)

The article is mostly about the pound in general (with no mass/force distinction) due its historical treatment as a weight. Perhaps the numerous incarnations of the pound should be in a generic Pound article, and Pound (mass) should be in a similar category to any other unit of mass in a specific system (in this case the Pound (mass) is a member of the "FPS gravitational" system of units. There should be a link to the Pound (mass) article from the Pound article of course, but it deserves no better treatment than the lb (of the "FPS engineering" system). There is a table of the FPS systems at Pound-force and at Slug (mass) which tabulates various FPS systems. It's a little less clear than it used to be; what was simply called "FPS engineering" is now "Engineering, absolute", and the "FPS gravitational" system of units is apparently clambering for some credibility by calling itself the "Engineering, gravitational" system - which of course has no use in engineering due to its offence to Newton's 2nd law. Where did the gravitational system come from? Maybe some reliable sources are in order. — Preceding unsigned comment added by 203.129.23.146 (talk) 08:05, 15 September 2011 (UTC)

"Use in commerce"

The "use in commerce" section is written a bit strangely; in part because it probably doesn't belong here. I propose we move it to Mass versus weight. Mass versus weight. Gerardw (talk) 10:36, 12 September 2011 (UTC)

I'm not in favour of creating a new article if that's all that's going to be in it. The section is making the point that pound weight in commerce invariably means mass and this should rightly be in the article. However, I don't think that it is necessary or useful to quote the NIST document verbatim at length. A summary of its contents is all that is needed. SpinningSpark 17:57, 12 September 2011 (UTC)

Sorry, formatted link wrong. I'm referring to existing article. Gerardw (talk) 18:21, 12 September 2011 (UTC)

I agree, a summary of the section that was removed should be reinstated with references to the relevant publications and Wikilinks to Mass versus weight. Martinvl (talk) 07:19, 20 September 2011 (UTC)

the origin of Troy weight

I am changing this:

"The troy pound takes its name from the French market town of Troyes in France where English merchants traded at least as early as the time of Charlemagne (early 9th century). The system of Troy weights was used in England by apothecaries and jewellers."

to:

"The system of Troy weights was used in England by apothecaries and jewelers since the early 1400s, and became the official weight standard for coins in 1527."

I am deleting references to the myth that the troy weight system originated at Troyes (see Zupko, History of British Weights and Measures, p. 19). Zyxwv99 (talk) 02:33, 16 November 2011 (UTC)

I don't have Zupko, and the later(?) work by Connor and Simpson did assign the story credibility. It is more than plausible for the following reasons:

• Troyes was an important market place where English merchants are known to have traded.
• There are historical French references to a "marc de Troyes" (which would have been 8 ounces of a French Troyes pound), although unfortunately there is no indication of its precise weight.
• The French "poids de marc"/"livre de Charlemagne" standard (important historical artifact kept in Paris [2]) was close to the later Flamish "trooisch pond". (30.60 g / ounce vs. 30.76 g / ounce) and is therefore very likely related to the "marc de Troyes".
• The English troy pound (31.10 g / ounce) is roughly in the same area.
• According to two sources by Simpson and Connor which I cited in Apothecaries' system#Weight standards named after Troyes, a 14th century source reported the numerical relation between the English and French troy ounces to be exactly 64:63. Based on the modern troy pound of 31.10 g / ounce this would indicate a French troy pound of 31.61 g / ounce, i.e. up to rounding errors the historical national French weight standard, the "poids de marc"/"livre de Charlemagne".

I can find no reference anywhere to a book "History of British Weights and Measures" by Zupko, so I assume that you are referring to Zupko's "British Weights and Measures: A History from Antiquity to the Seventeenth Century" (1978) or one of his "dictionaries" (various publication dates until 1985). The acclaimed [3][4][5] work by Simpson and Connor is much later, and of course they were familiar with Zupko and (IIRC) cited him.

For the moment I will revert your edit. Of course if you can make a good case that Zupko may still have been right and that the later work by Connor and Simpson is not sufficient to suppress what he says, then per WP:NPOV we can give all the details, use more general language, or remove uncertain information. But you will have to provide a lot more detail of what Zupko actually says. Unfortunately I don't have any of his books. Hans Adler 09:27, 16 November 2011 (UTC)

I stand corrected and acknowledge that I was at least half-wrong. Here is the relevant text from Zupko:

The name for the new system probably came from the French marc of Troyes, but it is certain that the English Troyes pound did not come from Troyes, France. The Troyes marc had an ounce equal to 472.1 BI (British Imperial) grains. There was a family of pounds known as troy in the northern trade of the period whose ounces varied from 483 to 472 grains. (Footnote: Specifically, the Swedish mark-weight pund had an ounce of 483.3 BI grains; the Danish solvpund ounce, 481.5 BI grains; the Scots tron pound ounce, 481.1 BI grains; the Bremen pound ounce, 480.8 BI grains; the Norwegian skaalpund ounce, 477.4 BI grains; the Amsterdam pound ounce, 476.6 BI grains; the Scots trois pound ounce, 475.5 BI grains; the Dutch troy pound ounce, 474.7 BI grains; and the French troy pound (Troyes marc) ounce, 472.1 BI grains.) The English troy pound took its name, like the Scots and Dutch pounds, from the Troyes marc, but took its standard from some pound of full weight, probably the Bremen pound whose ounce weighed 480.8 BI grains.

--Zupko (1977), British Weights and Measures: A History from Antiquity to the Seventeenth Century, pp. 28-9

I intend to study the work of Connor and Simpson. In the meanwhile, I am glad others here are approaching this subject with the seriousness it deserved. Zyxwv99 (talk) 01:43, 20 November 2011 (UTC)

Wow. When I read Connor and Simpson to write the Apothecaries' system article, I knew that I was missing something because I could see fragments of one of Zupko's books on Google Books. But I couldn't get hold of any of the books, and I wasn't aware how much I was missing! Hans Adler 02:00, 20 November 2011 (UTC)

I should point out that whatever I say about the book by Connor and Simpson is from memory or from how I cited them in Wikipedia. I used a library copy when I was based in Leeds. Here in Vienna the library doesn't have it, but I consider buying it. Hans Adler 02:09, 20 November 2011 (UTC)

Ronald Edward Zupko's books tend to be available through inter-library loan.Zyxwv99 (talk) 02:35, 20 November 2011 (UTC)

In "British Weights and Measures" by Colonel Sir C. M. Watson, pp33-34, an entirely different origin of the word 'troy' is advanced. The etymology is traced to 'troi' (balance) in Wright's English Dialectical Dictionary, and that troy weight is something one might do on a balance, rather than a bismar. In any case, such an etymology would releive the need to trace the scale by name to the continent. [grains are troy unless stated otherwise].

The arabic scale as available to king Offa is Kembah "wheat" (1/64), and Hebbeh "barley" (1/48), Kirat "carob" (1/16), Dirhem (1), Wukiyeh "oz" (10), Rotl "lb" (120). The silver series is based on a 45-grain dirhem, the gold on a 48-grain standard.

King Offa's system was a Penny (1/2), Shilling (6), Ounce (10), and Pound (120), along with grain (1/64) = silver kembah, based on the silver dirhem. There is also the merchant's pound (150). The silver penny displaced the sceatta and other bullion money, and was in turn copied widely on the continent. It is this system that one reads the 'pound of pennies' etc. The first act to refer to troy has this as the weight scale.

The transition from the 45-grain system to a troy 48-grain system, and the 437-grain ounce happened as a result of the English merchants failing to open the markets of the Hanseatic league, and turning their attention to those in the meditrerain sea. The 48-grain system is the avoirdepois of the arabs, the 437-grain is the wool-markets of italy.

When one takes king Offa's divisions, but apply it to the gold-scale, and use the hebbeh as the grain, one gets the troy scale directly.

The avoirdepoise scale, originally defined as 15 oz tower, came to be first 16 oz tower, then 16 oz troy, and then a separate prototype built in 1688. This averages 437.0 grains, but the act of 1824 defined the avoirdupois pound as "7000 grains troy", and then in 1855, the troy grain is defined as 1/7000 of the prototype pound.

It is interesting to note that the original metric system was to have separate troy (gram) and avoirdupoise (grave) weights. However, the system usuelle intervened, and by 1840, it was decided to extend the troy upwards to larger than kilogram units.

Wendy.krieger (talk) 08:14, 10 May 2012 (UTC)

Is "pound" a force or a mass (with reliable sources)...

Some of this is taken from discussion on the Wikipedia science reference desk http://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Science/2011_June_1#Pound-mass_and_pound-force.3F and also on the talk page for Slug (mass).

From one of my aeronautics textbooks, "at the surface of the earth, an object with a mass of 1.00 kg weighs 9.8 N or 2.205 lb, and an object with a mass of 1.00 slug weighs 32.17 lb or 143.1 N". The textbook is: Shevell, R.S. (1989) "Fundamentals of Flight", 2nd Ed, Prentice-Hall. The quoted statement is on page xix in the section titled "Conversion Factors between SI Units and English Units".

In Niu's "Airframe Structural Design", 2nd Ed (http://www.amazon.com/Airframe-Structural-Design-Information-Structures/dp/9627128090), on page 599 a unit conversion table shows a pound (lb) as a mass of "U.S. Customary Unit" equal to 0.4536 kg. Perhaps the confusion isn't about the system of units, but rather their origin. Perhaps (unverified) a pound is treated as a force in English FPS units and as a mass in US FPS units? This wouldn't surprise me, as the US and UK/English can't agree on another unit of mass, being the Ton. Fortunately they both seem to agree that a ton is a mass, just of different values.

In Gere's "Mechanics of Materials", 5th Ed inside the front cover, pound (lb) is tabulated as a force of U.S. Customary Unit equal to 4.44822 N. Even if numerically correct, I guess if the textbooks can't agree whether "pound" is a mass or a force it makes it a bit hard to define.

The U.S. Electronic Code of Federal Regulations (e-CFR) Title 14 (Aeronautics and Space), Subchapter C (Aircraft), PART 23—AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES, Section 23.397 (Limit control forces and torques.) specifies forces in pounds (lbs). Refer http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=17ff3d50f518bbb3a2472296a8435378&rgn=div5&view=text&node=14:1.0.1.3.10&idno=14#14:1.0.1.3.10.3.71.27

Appendix 4 of Houghton, E.L. & Carpenter, P.W. "Aerodynamics for Engineering Students" considers the pound to be the fundamental unit of imperial mass, where 1 pound = 0.453 592 27 kg (page 572).

Perhaps all we can do in a Wikipedia article is highlight its ambiguity as either a mass or a force, with conversion factors accurate on Earth's surface.

Highlighting the system of units to which pound-mass belongs (FPS gravitational) would also be helpful to clarify difference between use in engineering and absolute FPS systems of units. There is a table at Pound-force that highlights differences between systems of units, but the whole table needn't be copied to Pound (mass). Just mentioning the FPS gravitational system of units at Pound (mass) I think would be sufficient. I would guess that many readers are unfamiliar with the various systems, as I was, so highlighting that a pound isn't always a pound and that it depends on what system of units you're using might help stop the argument about whether a "pound" is a force or mass. Also, as shown above, it seems that textbooks can't agree on the "mass" or "force" terminology (though luckily conversions still work out correctly, on Earth's surface anyway).

I'm not sure exactly how the Pound (mass) article can be written to improve its clarity but someone with more experience as an editor might be able to come up with something that takes info from all reliable sources. There seems to be a fair bit of heresay and useless bickering (almost religious zealotry) in this talk page. Why must a "pound" be defined as either a mass or a force? Perhaps lets just call it an "ambiguous unit of weight", or at least put some sort of disputed flag against the article if the bickering is to continue indefinitely. As long as the article remains in its present form however, reader confusion will continue. 203.129.23.146 (talk) 06:27, 5 June 2011 (UTC)

I don't know where this stupid notion that the pound is primarily a unit of force and needs to be renamed for use as a unit of mass comes from, but when it is actually being taught at university level I guess we can't ignore it, and it sure seems to be causing a lot of grief by confusing people about the simplest things. Fact is that a pound is defined legally as precisely 0.45359237 kilograms. Since there is no ambiguity whatsoever about the kilogram – it has always been a unit of mass and nobody claims otherwise – there can be no doubt that this legal definition makes the kilogram a unit of mass. This agrees with historical usage from before the difference between mass and weight-force was known, in which the pound was also obviously a unit of mass, as there were physical "weight" standards and no corrections for different gravity were made when moving them. But the quotation in the article slug (mass) suggests that at some point physicists using the FPS system decided they wanted it to be a unit of force instead. Maybe to match the similarly odd practice of using the term "weight" for the force rather than the mass?

I think the sources of confusion can be summarised neatly as follows:

• "Weight" is an ambiguous term. Physicists and engineers use it to refer to a force. Everybody else, including many legal standards documents, use the same term to refer to mass. Neither usage is more correct than the other. Every use of the word must be interpreted in context.
• The FPS system is not really a system of units in the strict sense but uses the "pound" ambiguously. Consequently there are really two consistent FPS systems. One is based on the pound-mass (0.45359237 kilograms) and introduces the poundal as a unit of force. The other is based on the pound-force (0.45359237 kiloponds) and introduces the slug as a unit of mass. The conversion factor between the pound-mass and the pound-force is the same as that between the kilogram and the kilopond: the standard gravity of precisely 9.80665 m/s² = 9.80665/0.3048 ft/s², or roughly 32.174 ft/s². Using pound-mass + poundal or slug + pound-force hides the conversion factor (1 pound-force = 1 slug × 1 ft/s²; 1 poundal = 1 pound-mass × 1 ft/s²) and makes the location-dependent constant appear where it belongs: 1 slug exerts a force of 32.174 pounds-force. 1 pound-mass exerts a force of 32.174 poundals.

In the metric system there is no such ambiguity, and consequently there is no subjective need for a unit of mass equal to 1 kg/9.80665 (the mass that causes a force of 1 Newton, analogous to the slug). On the other hand, "the same force that is exerted by the standard gravity of a kilogram" does exist as the kilopond, a rare and obsolescent unit analogous to the poundal and not really part of the metric system. Hans Adler 07:39, 5 June 2011 (UTC)

PS: You may be interested in this source, especially the section "Mass v. weight". To quote:

I suspect that there is a difference between British and American use. The British obviously decided that if they were going to buy apples on the Moon, then they wanted a pound of apples to contain the same number as on Earth, so it should be mass. The Americans said rather that they wanted a pound of apples to feel the same on the Moon as the Earth, so it should be force. Personally, I refuse to buy a slug of apples wherever I am!

A further American [correspondent's] comment: "In my experience, the folks who insist that pounds are always a unit of force tend to be the physics students (probably to make F=m*a easier on first-semester students) while the engineering students will use pounds more as a mass. Ultimately, Congress defined the pound in terms of grams (not newtons) in the 1890s, and in the 1950s the remnants of the foot/pound using world got together and standardized on the same number of grams, so 'pound' is definitely a unit of mass. Of course, there's still 'pounds of force' used, abbreviated 'lbf', but that has to be differentiated from 'regular pounds.' The slug, as I mentioned before, is simply a convenient unit to use so that it takes 1 lbf to accelerate it 1 ft/s2. " I must point out that Physics students in Britain did not use pound as a unit of force! Nowadays, they all use metric.

I don't know what qualifications the author has, but this has been a pretty prominent page on the topic for a while, and he seems to have received a lot of feedback. It is easy to confirm that British, American and international standards organisations agree in defining the pound in terms of kilograms, not kiloponds or Newtons, that scales which actually measure force rather than weight must be adjusted (using reference weights) when taken to a place with (slightly) different gravity, and that beam balances and their weight pieces are never adjusted in this way. The idea that the pound is "really" a force and the other usage is incorrect appears to function as a shibboleth in the same way that some misconceptions about English usage (such as the absolute split infinitive prohibition) are routinely spread by teachers even though they are demonstrably wrong. Hans Adler 08:09, 5 June 2011 (UTC)

See also NIST Federal Standard 376B (preferred metric units for general use by the government), which says in footnote 2 on page 2: "In commercial and everyday use, and in many technical fields, the term 'weight' is usually used as a synonym for mass. This is how 'weight' is used in most United States laws and regulations." And on page 13:

NOTE: There is ambiguity in the use of the term "weight" to mean either force or mass. In

general usage, the term "weight" nearly always means mass and this is the meaning given the term in U.S. laws and regulations. Where the term is so used, weight is expressed in kilograms in SI. In many fields of science and technology the term "weight" is defined as the force of gravity acting on an object, i.e., as the product of the mass of the object and the local

acceleration of gravity. Where weight is so defined, it is expressed in newtons in SI.

Shortly after this note, which makes it clear that the source is ultracareful about the mass/force distinction, conversions are given as follows:

• 1 slug = 14.59390 kg
• 1 pound = 0.45359237 kg
• 1 pound-force = 4.448222 N
• 1 poundal = 0.1382550 N.

Hans Adler 08:24, 5 June 2011 (UTC)

I don't know what you're hoping your insults will achieve. I've never claimed that the pound is "primarily a unit of force", simply that its not universally treated as a unit of mass and that confusion is possible. SI/metric is unambiguous, but that's because there is a single coherent system of units. If you have a look at the table at http://en.wikipedia.org/wiki/Pound-force#Foot-pound-second_systems_of_units you will see that there are three separate FPS systems in use. If you insist there are two perhaps you would care to correct this table. It is also used in other articles, including at Slug (mass). I'm not familiar with the FPS absolute system (with poundals as the unit of force) but the FPS engineering units are familiar to me (as an engineer). I don't deny your pounds to kg conversion (I don't think anyone has). You're all wrapped up in legalities, so perhaps you could cite the particular law that you refer to. If that law explicitly defines a pound as a mass (as opposed to a mere conversion to a mass) then you should put it in the article and it would sort out some of the bickering in this talk page. Your claim of the practices of scientists and engineers being "odd" is inappropriate and irrelevant. That you think it odd doesn't mean anything except that you are apparently unfamiliar with science and engineering, which doesn't offer you much credibility to judge either. The rest of your rambling is interesting, but seeminly irrelevant to my comment you replied to. You seem to be taking this very personally though. Why are you so insistent that pounds must be treated as a unit of mass and that anyone treating it as a force is stupid or odd? Are you claiming that the US Federal Aviation Administration that maintains the previously cited regulation that legally treats pounds as a force is stupid or odd? Is there really any harm in highlighting some of the ambiguities mentioned throughout this talk page (and others) in the article? You thinking them stupid, odd or simple doesn't make them irrelevent. The conversions at the end are appreciated, except they also belong in the article. Your apparent inability to comprehend conversion between mass and force is a little curious, though it may explain why you think scientists and engineers are odd. 203.129.23.146 (talk) 09:39, 5 June 2011 (UTC)

Also, quoting NIST documents is fine, but I wouldn't have thought what appears to be some guy's personal homepage (http://gwydir.demon.co.uk/jo/) really counts as a reliable source. I'm not implying what he says is wrong, but at least I went to the effort of quoting prescribed textbooks from university engineering courses. 203.129.23.146 (talk) 10:04, 5 June 2011 (UTC)

Answer

I don't know where this stupid notion that the pound is primarily a unit of force ... came from It comes from the fact in the near Earth surface gravitational field the distinction doesn't matter. One pound (mass) produces one pound (force) of weight. Gerardw (talk) 01:41, 6 June 2011 (UTC)

The distinction between a pound (mass) and a pound (weight) does matter in precise work since, even if you stay at sea level on the earth, the gravitational acceleration g can vary from about 9.78 to 9.83 m/s^2, a range of ~0.5% Cardamon (talk) 07:35, 6 June 2011 (UTC)

Which is not to say there is anything wrong the article -- I think it reads fine as it is. Gerardw (talk) 01:41, 6 June 2011 (UTC)

I am fully aware of that, of course. My problem is this: There was the word "weight", which referred both to the mass of an object and to its gravitational force. Etymologically, the word is more closely related to the force, but in common language it is most often used for mass. The unfortunate decision to go with the meaning of "weight" that was a better etymological fit rather than the more common one led to a split between physics terminology (weight = force) and common usage (weight = mass). My understanding is that this split did not happen in the same way for "pound", even though etymologically (as it comes from pondere, weighing) that would also have made sense. But the most precise way to measure "weight" was always by comparing it to a reference body. Some such reference bodies existed as physical standards. Taking them to extreme locations, one would not manipulate them in any way to account for the different gravity; one would instead adjust spring balances. So it was clear that, as defined by the standard, the pound was a unit of mass, not force.

As a result, the pound was no longer a unit of "weight" in physics terminology, although it still was in common usage. If you combine "the pound is a unit of weight" (true in common language), "weight is a unit of force" (true in technical language) and the engineering FPS system (with the pound-force rather than the pound as one of the fundamental units), and add to this the unfortunate though understandable practice of saying "pound" for "pound-force" in that context – then it is in fact easy to understand how the misconception of the pound as primarily a unit of force arose. But anyone teaching physics or engineering at university level should still have been aware of the underlying facts and should have understood that the pound is somewhat ambiguous but primarily a unit of mass.

Yet every few months we get an editor here who insists that the pound is absolutely a unit of force and nothing else, or, as in this case, that it is sufficiently ambiguous that it's POV to say it's primarily a unit of mass. As I said earlier, I consider this situation to be analogous to that of the split infinitive prohibition and similar misconceptions about English usage. Perfectly reasonable advice ("use force rather than mass as a base unit for engineering", "don't overuse split infinitives as they sometimes sound artificial", "sometimes leaving out an adjective can make your prose more crisp") has a tendency to get more and more extremist as it is passed from one generation of teachers to another ("the pound is a unit of force, in all contexts", "never use a split infinitive, ever", "never use an adjective, ever"). But often there is one influential teacher to whom one can point as marking the beginning of the extremism. In the case of language misconceptions it's Strunk and White, who severely overstated a lot of their advice, apparently never expecting that their readers would take them literally instead of following the excellent example they were setting with their own style. I was wondering if there was a similar event for pound-force extremism. Hans Adler 06:44, 6 June 2011 (UTC)

psi = pounds per square inch = common usage = force per unit area, and weight/weightless = common usage = difference in one's weight between being on earth and in space (only change of course being gravity) implies weight "could" (not must) also be considered force in common usage. also, you seem to have contradicted the table at Pound-force that details the fundamental units of three FPS systems (is it incorrect?). 203.129.23.146 (talk) 21:41, 7 June 2011 (UTC)

In common usage the distinction doesn't matter. Can you conduct an experiment in your residence that would distinguish between the mass and the weight of an object? If one accepts modern humans have existed for 50,000 years (see Human) and Galileo did his Tower of Pisa rock thing in 1589, it's only been 0.008 of the (chronological) existence of humans the concept that of these mass/weight concepts began to be understood.

Wiktionary gives the primary definition as force [6], Merriam-Webster says it's a unit of mass and weight. [7].

Ultimately, whether "pound" refers to mass, weight/force, cake, or the act of hitting someone or something, currency, a place to municipalities put stray dogs or illegal parked automobiles depends on context.

Therefore, confusion between the two concepts is understandable and opening a dialog with a description of a query or statement as stupid is both unwarranted and unwise. Gerardw (talk) 11:16, 6 June 2011 (UTC)

Someone else has (correctly) explained the context of "stupid" at WQA, so I will be content with just telling you that pounding on my choice of words is not really appropriate, either. Of course confusion between the two concepts is understandable. The problem arises when people take care not to confuse them, but make incorrect claims about the conventional meaning of words. I can understand how this happens to laypeople, but if such misconceptions are taught by books and teachers at university level, as was claimed at the reference desk by the anonymous user, then it's a problem. Hans Adler 11:50, 6 June 2011 (UTC)

In common usage, pound = weight. The force concept is irrelevant to everyday life. In maths, lb-m = mass, lb-f = force. (I learned the difference at Secondary school.)

Archolman User talk:Archolman 00:04, 1 September 2012 (UTC)

Sorry to butt in here

but I've read dozens of books on weights and measures over the last twenty or thirty years. Unfortunately, I don't have them with me at this time, but here's the point. From everything I've read, governments throughout the world had weight standards that included sets of standard reference masses, i.e. "weights." This practice apparently goes back to the Bronze Age (e.g., Harappa, Mohenjo Daro, etc.). Also in use since ancient times was the balance scale, which, when used in conjunction with a standard reference mass, measures mass. Even if they didn't know the physics behind it (and of course they couldn't have) they had a de facto mass standard.

By the late 1700s, people in the Western world, at least, understood enough about physics that various national bureaus of weights and measures (now known as national standards institutes) began having the sort of discussions that we see here on this page, only perhaps more scholarly. As a result, by the time the USA adopted the English pound as a unit of mass in 1792, Thomas Jefferson was already reminding people of the difference between mass and weight, and explaining how the American pound is a unit of mass, and how in legal and commercial usage "weight" means "mass" in the physics sense.

In other words, you don't need to rely on a fine reading of NIST Handbook 130. You can go back to Jefferson and Franklin's original notes on the subject.

Or something like that. When I get around to it, I'll see if I can find some references.Zyxwv99 (talk) 02:57, 16 November 2011 (UTC)

I checked Jefferson's document Plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States. In that document he side-stepped the issue by refering to weights, not weight and only considering measurements using beam balance, not a spring balance. Of couse, in Jefferson's time the variations of gravity around the globe were understood - Jefferson himself being invovled in a discussion of where to site a pendulum that was to be used as a base unit of length. I seem to recall havign read that at some British weights were defined as being done at a specific temperature and air pressure. British legislators also talk about the kilogram being a "weight or mass". Martinvl (talk) 07:58, 16 November 2011 (UTC)

Capitalization

There seems to be a little edit war going on here with regard to the capitalization of certain words: pound, avoirdupois, etc. I've tried doing some research on this, but don't feel qualified to answer the question. Britannica Online and NIST don't seem to use the capitalized forms, except when dealing with proper nouns, as in "In 1834, the British Imperial Troy Pound and Yard were destroyed by fire when the Houses of Parliament burned."

On the other hand, maybe there is an exception for when a word is preceded by the definite article and is the subject under discussion, as in "the Pound Avoirdupois is a unit weight currently used...."

Zyxwv99 (talk) 18:53, 25 November 2011 (UTC)

It is a matter of style and the Wikipedia Manual of Style advises against capitalisation except for proper nouns. It is also the convention in science not to capitalise unit names when spelled out, even when they are named after a person. On both count pound should not be capitalised. SpinningSpark 17:15, 26 November 2011 (UTC)

Then shouldn't somebody revert the edit of 15:54, 24 November 2011‎ by User:Jc3s5h? I'm still a novice and don't feel THAT bold. Zyxwv99 (talk) 16:03, 27 November 2011 (UTC)

Go for it! Gerardw (talk) 16:11, 27 November 2011 (UTC)

Just Do It! WikiDMc (talk) 00:32, 28 November 2011 (UTC)

Tower pound image

Conversion to shillings does not give user useful information in the context of a Pound (mass). If tower pound is notable because of it's use in currency, let's mention that in the paragraph. 02:36, 14 December 2011 (UTC) — Preceding unsigned comment added by Gerardw (talk • contribs)

I agree that Tower Pound is not the measure of 'mass'. But since the article mentioned the Tower Pound, and I had the picture of the prototype, thought of adding it up. Anyways, its influence on the currency system cannot be neglected. In fact I would urge you to include the fact of its influence on the currency system in the main paragraph too... I believe an article must be holistic, rather than being strict. ~ DebashisM (talk) 03:08, 14 December 2011 (UTC)

As far as I know, the Tower pound was never used on the currency side. In the Middle Ages, people had a strong sense of fairness that was often a bit illogical. They would not have accepted having to bring more pounds of bullion to the mint than they would have received in coins. The Tower pound appears to have been a solution to this problem. The bullion you brought to the mint was weighed in Tower pounds, and then you got the same number of pounds in coins. Because the Tower pound was significantly heavier than the sterling pound used for minting (I forgot if it was the troy pound at the time or something else), the difference was enough to account for the inevitable losses in the minting process and the operation of the mint and the operator's profit. This is why it was called the Tower pound: It was used only in the Tower, where the London mint was located at the time. (Source of the information: A relatively recent scholarly book called Weights and measures in Scotland.) Hans Adler 07:36, 14 December 2011 (UTC)

Hans, truly speaking I do not know of the accuracy of the details. The picture I uploaded is of the Tower Pound prototype that I had clicked during my visit to the Tower in May 2011. It is based on what I read on the placed placard (wish I had clicked it too) and what was told by the present ravenmaster, Chris Skifes.

The currency pound was divided into 240 shillings. The weight of these 240 shillings combined was equal to the weight of a 'Pound'

DebashisM (talk) 08:17, 14 December 2011 (UTC)

The book that I got the information from is relatively recent and contains ground-breaking new research (such as the Scottish inch actually not being slightly longer than the English inch, after all) that hasn't become popular knowledge yet.

Yes, the currency pound was of course divided in that way until February 1971. But I really think it's off-topic w.r.t. the Tower pound, which shouldn't get so much prominence in this article anyway, given that its role is not completely clarified yet. Hans Adler 08:29, 14 December 2011 (UTC)

I saw the tower pound written in the article, and I had a picture of the prototype - If you feel its off the topic, then go forward and delete the same. I have no qualms... ~ DebashisM (talk) 09:16, 14 December 2011 (UTC)

Well, I primarily see coins in that photo. I guess the oblong thing on the left-hand side is a tower pound standard or something? If it is, then the way it's arranged may give a misleading impression. I am not asking to remove the photo. It's quite decorative, but maybe we shouldn't accompany it with text that suggests more than that. Hans Adler 09:24, 14 December 2011 (UTC)

DebashisM, the picture is a great addition to the wall-of-text article, we just want to get the caption right. Hans, I've added a note based on your information above; could you complete the citation? Do you think we should splinter the Tower pound section into a (very small) article of its own? Gerardw (talk) 15:40, 14 December 2011 (UTC)

Sooner or later we should probably have a separate Tower pound article, but first I must buy the book. In Leeds I simply borrowed it from the library, but there doesn't seem to be a single copy in all of Vienna. I will order it in January.

Sorry, what I wrote here wasn't fit for article space. That's why I qualified everything with "if I remember correctly". And in fact, based on a Google Books search it appears that I misremembered something. [8]

I do have access to a relevant paper by the same authors as the Scotland book. [9] I find the following rather interesting (and it also contradicts something else I said above):

The English troy ounce is recognized as a weight unit in very early English coinage, but its formal use in metrological definition is much more recent. It was not yet an official bullion weight in England in Pegolotti’s time and its subsequent formal introduction seems to have occurred in the late fourteenth century.31 The commercial pressure for this change almost certainly came from the important markets of the Low Countries, and indeed the English troy ounce is the same size as the ounce of the Bruges silver mark. Before this time, the principal ounce used in England was the ounce of Cologne, one of the principal European bullion markets, whose mark had widespread application in north Germany and the Low Countries. In English metrology, the Cologne ounce is more familiar as the ‘tower ounce’—a name acquired from its use at the Mint, in the Tower of London, where it controlled coinage operations until 1527. It is sometimes thought to have been restricted to use in the Mint, but in fact it was the general ounce until eventually superseded by the troy ounce.32 Its identification as the Cologne ounce was confirmed by Pegolotti.33"

It appears that I swapped the function of the troy and Tower pounds in my mind. Sorry for that. More later. Hans Adler 17:33, 14 December 2011 (UTC)

One should consult the wikipedia on 'silver penny' over the notion that the tower pound (ie king Offa's pound), is indeed the weight of 240 silver pennies as he might have used. A table of pennies minted from the pound of silver will show that before 1134, a tower pound yielded 240 pennies.Wendy.krieger (talk) 08:22, 10 May 2012 (UTC)

Spam alert

I am concerned about an edit made here by user 83.253.202.78 on 13 February 2012 at 19:42 hours. It appears at the bottom of the External links section and links to a typical online weights-and-measures conversion site called TinyTools Weight Converter. Like most of these kinds of sites, it has a lot of advertising. The site's Alexa rank is about 8 million. The user's edit history seems to consist entirely of posting links to this site. The Geolocater indicates that the user's IP address is in Dalarna, Sweden. Doing a search on Dalarna and TinyTools, I found a blog (here] where a poster in Dalarna described creating this website. Thus, I think this person is just posting links to his/her own website. Zyxwv99 (talk) 20:55, 13 February 2012 (UTC)

I've left a note at the IP's talk page. If he/she ignores the message, we could consider blocking him/her. JIMp _talk·cont 01:18, 14 February 2012 (UTC)

Thanks. I'm still new and wasn't sure what to do. Zyxwv99 (talk) 03:24, 14 February 2012 (UTC)

Hit vandals of any flavour with a big stick. It's always worth a chuckle, (Mwahahahhaha! The Power!) & especially satisfying after a long day :D Archolman User talk:Archolman 00:25, 1 September 2012 (UTC)

Definition of "grain".

There is no definition of "grain". I don't have the time for research/writing, or I would do it.

Go on, you know you want to! Define "grain"!

Archolman User talk:Archolman 00:34, 1 September 2012 (UTC)

Yes, there is:

An avoirdupois pound is equal to 16 avoirdupois ounces and to exactly 7,000 grains. The conversion factor between the kilogram and the international pound was therefore chosen to be divisible by 7, and an (international) grain is thus equal to exactly 64.79891 milligrams.

Jc3s5h (talk) 00:50, 1 September 2012 (UTC)