Talk:Weight

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This page is basically a long argument that the historically correct usage of weight is mass. But the origins of words do not determine their proper use, and anyways, weight was first coined back when people didn't have any concept of the distinction between mass and force due to gravity. I've removed the bit about scales, since it is the least sensical - scales measure force due to gravity in circumstances where it will ideally be proportional to mass, so to claim they are truly measures of one or the other seems kind of absurd. The rest could stand some editing, though. The distinction between pounds and pound-forces is not supported by older physics texts, which usually use pounds as forces and slugs for mass, while acknowledging a different system where pounds are masses and poundals are forces.

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Admitedly the terminology for pounds is confusing, but you will find that the legal definition of pounds in the United States today is as a unit of mass.

A balance scale compares masses, it does not measure force due to gravity. You put the object to be weighed on one end of the balance. You then add weights of known mass on the other end of the balance, until the balance is level. This procedure requires acceleration due to gravity to work, but doesn't depend on the actual value of the acceleration. So it is a measure of mass, not force due to gravity. -- SJK

Disagree. You can use the exact same device to measure charges in an electromagnetic field, or the relative strengths of two springs. It's only measuring mass when you decide to interpret the results as mass; when you decide to interpret them as forces, it's measuring forces. It doesn't make any sense to talk about what a device is "truly" measuring when it's measuring two coincident things! I really think this article's emphasis on whether or not usages are correct, rather than what weight is, is a bad thing, and would vote for this passage to be removed and others to be rewritten, but I don't want to get into a back and forth edit war.

But when you use it to compare masses, the result does not depend on the force due to gravity. A scale balance will give you the same result on Earth as it will on Mars. A spring balance will not. -- SJK

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However, scales depend on factors other than the masses and force due to gravity. When you try to use scales underwater, and the objects being weighed do not have the same density, you get incorrect measurements. Actually, this phenomenon (Archimedes' Force) occurs in any medium other than a vacuum, but it is almost negligible in air. In general, if you apply some vertical force on the masses, you mess up the scales' readings. What they really do is compare the forces acting on each side of the balance. Thus, I would not say that they measure mass. For something to measure a quantity, its output has to depend only on that quantity. For example, a barometer always measures air pressure; although it can be used to calculate elevation (if you know the relationship between elevation and air pressure) that is not what it actually measures. --KA

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Minor correction: scales do not measure forces. If they did, the doctor's office couldn't weigh you with those small masses on the scales. Scales compare torques: when torques are imbalanced, the lever arm rotates, when the lever arm holds still the torques are the same (in opposite direction). Add a little geometry, and you can convert the torques to the net force directed radially. That is as much as you can say about a balance without adding other factors. If the forces are applied to the ends of strings attached to the lever arms of the balance (much the same way many balances have susbended trays on them) you can tell the direction of the force (a useful way to convert radial force to net force). To get to a measurement of mass takes: 1, a unidrectional field (maybe, this one could be corrected for with the strings, I'd have to think more to say for sure); 2, a uniform field (at least uniform enough that the geometry of the balance and/or the object does not effect the net force); 3, a field that is only proportional to the quantity you wish to measure.

BlackGriffen

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Maybe this page explains what I was trying to get across better http://ourworld.compuserve.com/homepages/Gene_Nygaard/weight.htm

The comments still apply. Ancient peoples couldn't be talking about mass as opposed to gravitational force if they didn't have distinct concepts of each. Scales measure mass when you use masses for reference and forces when you use forces for references, and so to speak of them truly measuring one or the other is silly, modulo KA's comments above. And, btw, does anyone know if there is an official usage for the pound in Britain or elsewhere? America hardly determines universal standards for units, as the gallon proves.

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The pound (technically, the pound advoirpois) is defined in the same way in both countries, since the 1950s, in terms of the kilogram. -- SJK

Ok. Well, one still finds a considerable body of literature using pounds exclusively as a unit of force, especially in derivative units (e.g. 550 foot-pounds/second = 1 horsepower), and it would be somewhat hypocritical to talk about historical usage and then turn around and label these as simple obsoletes. I think that, when usage is varied, an article should reflect varied usage and not try and impose a false order on reality.

An example of a case where common usage refers to force, and not mass, is when people say objects in space are weightless.

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I'm not saying that weight cannot mean force, just that it is historically mistaken to claim that it should only mean force, or that people who say that "I weigh 50kg" are somehow being inaccurate.

Also, yes people in past centuries weren't entirely clear on the difference between mass and force due to gravity, but most of the time it was mass, not force due to gravity they were worrying about. If you weigh out 5 troy ounces of gold, do you want 5 ounces mass or 5 ounces force due to gravity? You are interested in the mass, not the force due to gravity. Similarly, if an apothecary weighed out 1 grain of some medicinal substance, they wanted 1 grain mass, not 1 grain force. Weighing is (and more importantly was) most commonly done to determine the amount of substance, not to determine how heavy it is. So even if they weren't entirely clear on the difference, they wanted mass. -- SJK

On Earth, weight refers to that quantity which is both mass and gravitational force because the two are identical there, and elsewhere the meaning is considerably clear. It doesn't matter which of mass and force people really wanted to be talking about back when they didn't distinguish the two, because they didn't distinguish the two. Nowadays the word tends to mean force when there is a difference, though it still is used to mean mass a lot of the time. Language changes. We want to reflect use, not what we believe use should be, or what we believe historical use better represented - actual historical use being of course both simultaneously.

The bit about scales I'd like to see removed, since as argued above it is incorrect, and the bit about weight historically meaning mass I'd like to see altered, since it is misleading at best. I'd also like to see the approach to legal resolutions straightened out, since we seem to accept the universality of the recommendation that pounds be mass but treat the recommendation that weight be force as a mere suggestion. If I change the article to take these into account, can I trust that you will not revert it, at least not without further discussion?

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How about:

Weight, in physics the force that gravity exerts on a body. Compare mass.

What's all the fuss about? Sheesh. Ed Poor

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At the very least, we should make clear that, historical usage aside, this encyclopedia uses the term weight to refer to force due to gravity. Otherwise, every link to this article will leave the reader confused: "Which meaning of weight are they currently using?" --AxelBoldt

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I've finally done it, I've gone and blown it all up. Right now the article says that weight should mean force, at least in technical literature, which is possibly overkill but already present in the new introduction, and certainly in line with both what seems to be wikipedian consensus and the CPGM resolution. The stuff about weight historically meaning one or the other has been removed, since they were not distinguished and it is a bad idea to try and determine which people really meant, and the stuff about scales actually measuring one or the other has been removed, as the above comments (not all by me) provide ample justification for such a change, I'd say. I apologize for how radical this edit is and how completely it reverses the position, and would be more than happy for SJK or someone else to temper the article somewhat towards accepting mass as a valid alternate. I just don't think we should try and argue that it is somehow a better meaning.

(This means that most of this Talk page is now obsolete...)

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Oops, I did it again (with apologies to B. Spears) I missed the SI thing at the bottom. So, let's discuss how to make the article serve all its purposes

• distinguish between weight and mass, so we know which is which.
• point out that they're still used interchangeably (at least by laymen)
• give some sort of endorsement to the scientific usage.

I think the current article does just that, no? --AxelBoldt

When discussing scientific or engineering matters, I take pains to use force (measured in N-m or lb-ft) to mean force. But contemporary usage is fraught with references to 'weight' which "really" refer to mass. I used 'weights' on a balance scale to 'weigh' objects and determine their 'weight' (really mass, of course) in high school science classes.

N-m is work or energy, not force. --AxelBoldt

How weighty an issue is this, anyway (wink)?

Ed Poor

Too much jargon

Some people seem to have lost sight of the fact that this is an encyclopedic article, not merely a guide ot the interpretation of the jargon of particular petty priesthoods.

This is also a word is quite general use, and with quite specific meanings—meanings often at variance with the jargon of those priesthoods.

We would better serve our readers by making these distinctions clear. Enough of this burying your heads in the sand. Gene Nygaard 14:46, 17 Dec 2004 (UTC)

Scope of this article

In determining what should be included in this particular article "Weight" it is instructive to look at how the word is used on the pages on the "What links here" special page.

However, keep in mind that most of these are nothing more than brief mentions, not using any actual measurements of anything called weight.

Some might quibble with my characterization of almost every individual linking article, but if you want to comment on that it would be more helpful to discuss a broader class of them by the context in which "weight" is used in that group of articles.

Omitted are a redirect from Falling and five double-redirects under it.

I stubbed a new falling that includes a basic classical physics definition and some other lovely descent-related stuff. --Tony Sidaway|Talk 22:30, 2 Jan 2005 (UTC)

What links here? sorted by meaning

means mass Balance
Clinical depression
Fetus
History of computing hardware
Sputnik 1
Tupolev Tu-144
W. G. Grace
Stone
Physical collision
Clozapine
Weight training
Sinker (fishing)
Universal Product Code
Valproic acid
Commercial at
Tael
Tandem bicycle
Jam
Power-to-weight ratio
Haloperidol
Fluphenazine
Typical antipsychotic
Risperidone
Crash test dummy
Rechargeable battery
14 (number)
Canon de 65 M(montagne) modele 1906
Canon de 75 M(montagne) modele 1928
Unsprung weight
Oka (measure)
Cephalic disorder
Local food
Avoirdupois
Tonnage
Talk:Grain
Self image
Obolus
Wikipedia talk:WikiProject Space missions
Dick Tiger
BattleTech:Technology
Comptometer
talk:W. G. Grace/temp
oka (measure)
ThinkPad X40
CWT
Hundredweight
Little Britain
Ra's al Ghul
Blood donation
Trevalla
Rolled Homogeneous Armour
Terex Titan
LCM-8
Units of measurement
Aston Martin DB7
Devaluation
Tower pound
British 81 mm mortar
Thrust-to-weight ratio -- also used for an imaginary force
Code Adam
Displacement (fluid)
RCMP recruiting
User:Patrick/w
Haugh unit

means force due to gravity Aeronautics
Aerodynamics
Centripetal force
Fall
Hail
Mass
Oscillation
SI derived unit
Weightlessness
Relative density
Gravitational constant
Specific impulse
Gee
Talk:Newton (disambiguation)
Newton
Talk:Newton (unit)
Freefall
Connection
Pound-force
Terminal velocity
Thermostat
Structural analysis
Unit of account
Soap bubble
List of topics (scientific method)
Boussinesq approximation
NLGI Grade
Image:Aeroforces.jpg
Allen Carr
Talk:Relative density
Wheelbase
Diplexer
User talk:GK
Normal force
Apparent weight -- but a variant meaning of word without adjective
Gravimetry
Animal locomotion
Animal locomotion on the surface layer
Decompression trapeze

means density Bone
Apheresis

means an object Gravity
Weight training
Timeline of gravitational physics and relativity
History of perpetual motion machines
Diving shot
Spotter
Hydraulic accumulator
William Congreve (inventor)
Tsukemono

means both mass and force due to gravity, may be different people, esp. in talk Pound
Scientific method
Amedeo Avogadro
Talk:Mars Exploration Rover Mission
User talk:80.255/archive 1
Wikipedia:Reference desk archive/June 2004
Talk:Internet
Weighing scale

could mean either mass or force due to gravity, or meaning unclear Aircraft
Mineral
Metallurgy
Talk:Sputnik 1
Buoyancy
Bulldozer
Weight bearing
Bar (unit)
Naruto geography
Hip dysplasia
Outrigger
Powered armor
Talk:Crash test dummy
Monosoupape engine
Tamp
Burden

means force, but not due to gravity, or not just gravity Action stroke dance notation
Thrust-to-weight ratio -- also used meaning mass

mathematics jargon meaning Weight function

do not use weight (other than link to here) Scale (measurement)
Fundamental unit
Heavy
Human physical appearance
List of physics topics R-Z
Cranial electrotherapy stimulation
Magic School Bus episode guide
List of -ight words
Wikipedia:Concise
User:Anthony DiPierro/Everything else

means none of the above Deadbolt

What links here? Sorted by units used for "weight"

This is the most instructive part—looking at how the word "weight" is used when it us used with actual measurements.

Note also that there are hundreds of other pages on Wikipedia which do measure other quantities identified by weight, but which do not link to this page. I'd bet that they are even more unbalanced towards the measurements of mass than this listing.

mass, uses kg, lb Pound
Sputnik 1 -- uses kg, lb
Tupolev Tu-144 -- uses kg only
W. G. Grace -- uses kg, stone (no lb)
Weight training -- uses lb, kg
Sinker -- uses oz, lb
Commercial at -- defines at, arroba in terms of lb
Tael -- defines tael using oz troy and avdp, g
Crash test dummy -- uses kg, lbs
Canon de 65 M(montagne) modele 1906 -- uses kg only
Canon de 75 M(montagne) modele 1928 -- uses kg only
Oka (measure) -- just defines oka in kg
Avoirdupois -- just defines lb in grams, other units in lb
Tonnage -- just defines various tons in terms of kg or lb
Obolus -- just defines in terms of grams
Dick Tiger -- uses "pds"
BattleTech:Technology -- uses tons
talk:W. G. Grace/temp -- uses stone only
oka (measure) -- just defines in kg
ThinkPad X40 -- uses kg, lb
CWT -- just defines in lb
Hundredweight -- defines in kg, lb
Little Britain -- uses stone
Ra's al Ghul -- uses kg, lb
Diving shot -- uses kg, lb
Trevalla -- uses kg only
Terex Titan -- uses tonnes only
LCM-8 -- uses tons (probably long tons) only
Units of measurement -- just defines lb in kg, kg in "weight" of liter
Aston Martin DB7 -- uses tonnes only
Tower pound -- just defines in grains
British 81 mm mortar -- uses kg only
Code Adam -- uses lb, kg
Tsukemono -- uses kg only
Displacement (fluid) -- uses long tons
RCMP recruiting -- uses kg, lb
User:Patrick/w -- uses kg
Ruby Lin -- uses kg, lb
14 (number) -- just definition of stone in lb

force, uses newtons, kgf, lbf Specific impulse --uses N, and sort-of uses gf
Newton -- just defines, doesn't use, N
Talk:Newton (unit) -- just N, kgf definition
Normal force -- uses N
Animal locomotion on the surface layer -- uses dynes only

use no units for "weight" I'll leave these jumbled together and unlinked.
Aircraft Aeronautics Aerodynamics Bone Balance Centripetal force Clinical depression Fetus Fall Gravity History of computing hardware Hail Mass Mineral Metallurgy Oscillation Scientific method SI derived unit Weightlessness Relative density Stone Gravitational constant Collision Amedeo Avogadro Clozapine Scale (measurement) Universal Product Code Valproic acid Gee Fundamental unit Timeline of gravitational physics and relativity Talk:Newton (disambiguation) Freefall Tandem bicycle Talk:Sputnik 1 Jam Power-to-weight ratio Connection Pound-force Heavy Haloperidol Fluphenazine Typical antipsychotic Risperidone Rechargeable battery Human physical appearance Unsprung weight Cephalic disorder Local food Buoyancy Talk:Mars Exploration Rover Mission Terminal velocity Thermostat Structural analysis Talk:Grain Unit of account Bulldozer Weight bearing Self image Wikipedia talk:WikiProject Space missions Bar (unit) Soap bubble Naruto geography User talk:80.255/archive 1 List of topics (scientific method) Boussinesq approximation List of physics topics R-Z Comptometer Hip dysplasia History of perpetual motion machines Cranial electrotherapy stimulation Magic School Bus episode guide Outrigger Blood donation Spotter Rolled Homogeneous Armour Devaluation Powered armor Talk:Crash test dummy Hydraulic accumulator Action stroke dance notation William Congreve (inventor) Monosoupape engine Deadbolt Wikipedia:Reference desk archive/June 2004 NLGI Grade List of -ight words Image:Aeroforces.jpg Allen Carr Talk:Relative density Wheelbase Talk:Internet Diplexer Weighing scale Apheresis User talk:GK Apparent weight Gravimetry Animal locomotion Tamp Wikipedia:Concise Decompression trapeze User:Anthony DiPierro/Everything else Haugh unit Burden

restoration

Body wt is a common (perhaps the most common) use of the word and predates the largely theoretical distinction between wt and mass. 99+% of our readers don't know the difference and should be at least educated, oriented, and sent to their topic of interest. I hope it doesn't pain you too much to retain the two small sections at the end even though I applaud your efforts at scientific rigor. alteripse 02:46, 5 Feb 2005 (UTC)

Latest edits by CYD

I'm glad to see that you are finally coming to your senses about this, CYD. Your last edit is much more reasonable than what you reverted to earlier. With a little more tweaking, it might even work.

However, your comment about "remove self-promotion link" is misplaced. That was here before I ever started editing Wikipedia (my first edit of any kind was 6 Dec 2004). You can see where it is mentioned in an unsigned comment here on this talk page; if you look in the history, you can see that it, and the link on the article page, were added more than three years earler, see talk page Revision as of 22:47, 2 Dec 2001 203.109.250.xxx . Though I wouldn't know how to do it myself, I have no doubt that somebody could track down that user as being someone other than me. Or maybe I did; some edits by 203.109.250.xxx are signed [[SJK]] and entries signed by SJK also appear on this talk page, and the comment about adding the link is worded as an extension of some of those comments.

Nonetheless, I don't think it would be appropriate for me to reinstate your deletion of the External link to my web page, though I have no objection if someone else choses to do so. Gene Nygaard 03:46, 5 Feb 2005 (UTC)

Who is more careful?

The statement that "In the physical sciences, people are usually more careful about the distinction between weight and mass" is a crock of nonsense.

First, it assumes facts not in evidence—that there is in fact always a "distinction between weight and mass". It is a logically flawed, circular argument to assume this as a fact in the first place, and then use it to prove the same point.

Second, the usage of the word "weight" is much more consistent and uniform in commerce than the usage of the word "weight" in the physical sciences.

• Commerce usage:
  • Weight is never a force when anybody talks about net weight of anything.
  • You never hear of any government regulator mistakenly testing a scale used in commerce for its accuracy in measuring force rather than its accuracy in measuring mass. But then, they have a lot of shoulders to stand on; this was already old hat when Hammurabi included provisions regulating this weight in his Code of Laws some 3750 years ago.
  • The troy units of weight, which are still used in commerce (even in the 21st century enjoying a special exception from the metrication laws of places such as Australia and the U.K., are always units of mass, never units of force. Those troy units were also the preferred units of Isaac Newton in the physical sciences (perhaps because he could borrow the scales of his employer at his day job as Master of the Mint), even though he liked the French toises, pieds, and pouces for length.
  • Weight is never a force when anybody talks about carcass weight, even if they spell it carcase weight.
  • Weight is never a force at the livestock auction markets in Saskatchewan, whether they are selling hogs in dollars per hundred kilograms or cattle in dollars per hundred pounds, which is no matter how you look at it a pretty weird way of doing things.
  • Newtons are never legal units for the sale of goods by weight.
• Physical sciences usage:
  • Despite CYD's wishful thinking, the terms atomic weight, molecular weight, and formula weight are alive and thriving.
    • Just go look at a few of the zillions of Periodic Tables of Elements cluttering up the World Wide Web, and see how many of them use atomic weight (on many of them, you get details like this by clicking on the symbol for each element). Many of these are posted by educational institutions around the world.
    • Google—

            "molecular weight"                     3,250,000 hits
            "molecular weight" site:harvard.edu       12,600 hits
            "molecular weight" site:nist.gov           5,490 hits

• • The rocket scientists at NASA tell us that the weight of the Apollo 11 Lunar Module at liftoff of its ascent stage was 10,776.6 lb.
  • The thrust-to-weight ratio of that LM, in normal NASA usage of this term, was about 0.35 or less (they usually omit the units). Do the math. And the dimensional analysis.
  • The verb to weigh is considered correct when used to mean "to measure the mass of" something, even when used by those who would not use the noun weight for the result of that weighing. Using to mass as a verb with this meaning is substandard usage which grates on the ears of most people, including many chemists and physicists.
  • Physical scientists are often called on by their governments to help in the development of weapons of war. Go look into how the term throw weight is used. What are the proper SI units for this quantity? Hint: it is the same units used in various treaties.
  • Then, of course, there is Henry Cavendish's paper, Weighing the Earth, a title never to be spoken aloud in an astronomy class.
• Deceptiveness in the "physical sciences" classification:
  • Those making this claim would like to have us believe that they are making broad generalizations about the entire scope of science and technology in general. So what we need as an aid to this discussion is the following glossary entry:
    • Physical sciences: a term referring the mechanics sections of introductory college physics textbooks published after 1980.
• The physical sciences usage they'd like us to forget about:
  • Engineering.
  • The measurement of body weight by biologists, a measurement of mass. Same for paleontology as well.
  • The measurement of human weight in the medical sciences, another measuremnt of mass.
  • Drug dosages in milligrams per "kilogram of body weight" in veterinary science as well as in medical science.
  • The use of "bushels by weight" and "finishing weight" of a hog in agricultural sciences.
  • Archaeologists measuring the weight of bowls in grams.
  • In aeronautics, the "empty weight" and "maximum takeoff weight" of an airplane.
  • The term "dry weight" as it is used in various sciences. I've never seen a "dry weight" measured in newtons.
  • The weight of a crash test dummy.

Then there's that heavy cream those physical scientists use in their coffee. No matter which definition of weight we use, a liter of heavy cream will weigh less than a liter of light cream! — Gene Nygaard 11:11, 5 Feb 2005 (UTC)

I think the assertion that, in the physical sciences, "weight means a force" is mostly correct. In any case, the physical sciences do not include Engineering, biology, paleontology, medical sciences, verterinary science, agricultural sciences, archaeology, or aeronautics (in the sense of engineering). I don't know how to categorize the use of crash test dummies. --SV Resolution(Talk) 20:30, 10 November 2005 (UTC)

The "physical sciences" is a context-sensitive term, with many different variations in meaning. It often includes engineering. See, e.g., Webster's Third New International Dictionary and various versions in the history of the physical science article. It is also very often used as a distinction from "social sciences" (and, in that context, including the biological sciences).[1]

But none of that really matters in the face of 7,390,000 Google hits on the exact phrase "molecular weight", including 9,130 of them on "site:en.wikipedia.org". (I must have hit Google on a bad day in the numbers quoted above.) That doesn't even get into "mol. weight" and "mol. wt." and "atomic weight" and "at. wt." and "formula weight" and all the similar usages.

Those are usages in what would be called the "physical sciences" in any of its various definitions. Gene Nygaard 12:36, 11 November 2005 (UTC)

How about "In the physical sciences, weight generally means the interaction of matter with a gravitational field"? --SV Resolution(Talk) 21:00, 11 November 2005 (UTC)

For discussion of the atomic weight, here are the google hits:

Atomic weight: 3.130.000

Atomic mass: 25.300.000

Must you have searched on a really bad day. I think this should be enough to show that, even in popular use, atomic weight is dead and buried. And, being a scientist myself, never heard about any textbook confounding weight and mass. This is an encyclopedia: the commerce usage should be noted, it's a reality in itself, but in the scientific definition (wich is the one we are mading the article for) no ambiguation should be left. Tercer 23:07, 26 December 2006 (UTC)

Disambig

This needs to become a disambig. Or at least we need weight (disambugation). --Piotr Konieczny aka Prokonsul Piotrus ^Talk 21:12, 22 October 2005 (UTC)

Deleted - a centripetal accleration field

I deleted the phrase "a centripetal accleration field" refering to gravity. I don't know why this is in there, but it makes no sense to me. What is a "centripetal acceleration field" ? And why does that make anything clearer? Fresheneesz 02:50, 17 April 2006 (UTC)

Oops-History clarification

I wasn't logged in when I made the alterations at 12:24, 17 Apr 2006, (Changed definition to note common usage. Corrected definition of physical science usage to that currently accepted in physical science---i.e. depends only on gravity, and directed downward.)--Alma Teao Wilson 03:10, 24 April 2006 (UTC)

It might be helpful to emphasise that the original (and to my mind correct) FPS unit of force was the poundal, not the pound, being the force equivalent to a mass of one pound accelerated at one foot per second per second.

Use of pound instead of poundal was simply a careless colloquial mistake.

Not really. It's use was usually intentional. The use of the pound-force predates the use of the poundal (invented ca. 1879), though the pound-force wasn't ever a well defined unit until the 20th century, and even today it doesn't have an official, universal definition as the corresponding kilogram-force does (it is 9.80665 newtons). Gene Nygaard 13:04, 5 August 2006 (UTC)

Pound convert

Okay, I've been watching the pound discussion for years now (2 to be precise), and I'm pleased with the article that they have now with regards to mass vs weight (I will always use weight as the force acting on an object due to gravity in this post). I think the real discussion on mass vs weight belongs here. So, as an initial informational post, here I add my two bits (well, more like 50 bucks) of thinking about this for two years.

1. The layman, on average, knows the difference between mass and weight (I did a "scientific study", which proves nothing, but in my sample, the numbers are statistically significant
2. Officially, the pound is a unit of mass. Many similar units (ton, ounce) are as well. This has been defined by several standards bodies. Technically it's official.
3. Many people use pounds when they are thinking of weight, mostly they are unaware that de jure pounds is mass. In the US, pounds (et al) is the de facto standard.
4. in many cases the usage of these terms is unimportant. ("What size of cereal box did you get?" "I got the 24 oz package." i.e. Even if they are thinking (if only subconsiously) "force" and the government regulates the "mass" of the box. Everything still resolves correctly.
5. Even though it isn't technically correct, many "scientists" and non-laymen, still fall into the same trap. I've seen in textbooks targetting ages 10-30 mentioning something like "if you weigh 100 pounds on earth, you will weigh about 40 pounds on Mars." These are people who should know better, and are used to show the distinction between mass and weight, but can't keep the units correct. These kinds of documents have contributed to the laymen's usage. (Official government-sanctioned textbooks for use in public schools, and publications such as LIFE).
6. Theoretical Physics books (for example The Elegant Universe by Brian Greene, page 148), with authors who have to know the difference, continue to perpetuate this technically incorrect, usage (Brian Greene mentions the Planck Tension (clearly a unit of force) and provides an estimate for it's value, expressed in Tons (technically a unit of mass)).

I'm comitted to ensuring that Wikipedia maintains this point of view. Sadly, I don't have the energy to really watch this page. If anyone would like a copy of my (non-wikipedia worthy) studies, I would be willing to provide them. More in-depth references on any of these things (which are wikipedia worthy, are available on request. The best way to obtain this information would be by leaving me a message on my talk page.

McKay 07:28, 15 August 2006 (UTC)

I'm not certain item #5 should be regarded as a mistake. It's clear from context that they are referring to a force due to gravitation. There would be an improvement in clarity if they had used newtons, certainly. --Yath 14:03, 15 August 2006 (UTC)

Yes, they are referring to a force. That's exactly what I'm saying. Canonically, the Ton is a unit of mass, and shouldn't be used in force calculations, the ton-force should be used. McKay 18:46, 15 August 2006 (UTC)

But it is also used as a unit of force, so it can't be "incorrect". The government's pronouncement doesn't override common usage. --Yath 19:58, 15 August 2006 (UTC)

Yes, and that's exactly what I'm trying to say. It's not just laymans usage, it's common usage. McKay 02:14, 16 August 2006 (UTC)

Let's tweak your wording a bit. I'd put it more like this:

1. The layman, on average, knows the difference between the amount of stuff they have and force due to gravity. Both mass and weight are ambiguous terms, with several meanings each.

2. Officially, the pound is a unit of mass. Many similar units (ton, ounce) are as well. This has always been true, ever since pounds were first used.

3. Many people use pounds when they are thinking of weight, mostly because the weight they are concerned with is the very same thing as mass in its physics jargon meaning.

4. In many cases the usage of these terms is unimportant. ("What size of cereal box did you get?" "I got the 24 oz package." i.e. Even if they are thinking (if only subconsiously) "force" and the government regulates the "mass" of the box. Everything still resolves correctly, unless you happen to be talking about a 400-ounce bar of platinum or something like that—even for those who misunderstand the meaning of "weight" in this context, who are in many cases those with a high degree of education in the sciences. You'd think that the fact that there is nowhere on Earth where newtons are legal for this purpose, and that everyone (even most labels in the U.S.) uses grams and kilograms, would be a big clue, but some people can think of all sorts of ways to ignore the obvious.

5. Even though it isn't technically correct, many "scientists" and non-laymen, still fall into the same trap. I've seen in textbooks targetting ages 10-30 mentioning something like "if you weigh 100 pounds on earth, you will weigh about 40 pounds on Mars." These are people who should know better, and are used to show the distinction between mass and force, but can't keep the quantity being measured straight in their minds, and thus use correct units. This would be true if we were talking about pounds-force, but in most cases in which people measure their weight, as in the medical sciences and in sports, pounds-force are not proper units for it.

6. One pound-force and one ounce-force and at least three different tons-force do exist. So do kilograms-force (and a megagram-force is one of the tons-force just mentioned), though since they are not a part of the modern metric system, the International System of Units, their use has been deprecated since 1960. There are, however, no troy pounds-force nor troy-ounces force. Unlike their avoirdupois cousins, and unlike grams and kilograms, the troy units of weight never spawned a unit of force of the same name. Gene Nygaard 22:16, 19 September 2006 (UTC)

Note that point '1' above appears to be one person's reporting of a unofficial survey, with a result that a statistically significant group of respondents apparently identified "weight" as a phenomenon of force as opposed to mass. Why should that observation need re-wording? (You speak of ambiguity in the possible interpretation of the term "mass". Could you please elaborate on that?)

In point 3, the argument was being made that many people have been persuaded, for better or for worse, to buy in to the notion that the term "pound" really does refer to a phenomenon which varies according to the gravitational field surrounding an object. This is probably due to the perpetuaton of factual misinterpretation such as what's pointed out in (5).

Some government bodies specifically state that the term "weight" is simply loaded with too many conflicting interpretations to be considered appropriate for "official" documentation. In Canada, the legislation defining systems of measures acknowledges that term "weight" appropriately refers to the same physical phenomenon as "mass". But the same legislation then goes on to state that the term "weight" should be avoided wherever possible in all government-issued documentation due to ambiguity of the layperson's interpretation of meaning, and explicitly replaced with either "mass" or "force".24.89.207.7 03:00, 28 February 2007 (UTC)

Mechanics

If someone wants to split off a Weight (mechanics) article for the usage common in mechanics, fine. Or whatever disambiguation is appropriate; not Weight (physical sciences), however, since things like molecular weight remain in such general use in the physical sciences.

If it were split off, the primary disambiguation needs to remain at the most general and often-used meaning.

Just be sure to take the dozen or whatever links along with you, from the "what links here". Gene Nygaard 14:59, 29 September 2006 (UTC)

I don't think that would be a good idea. Mechanics already has a version, acceleration due to gravity, and, despite intentions of some here to eliminate scientific rigour, even in the "popular" version there should be the truth displayed. This is a encyclopedia after all, not some popular term glossary.Tercer 23:03, 26 December 2006 (UTC)

It has nothing whatsoever to do with "scientific rigor". It has to do with the quite proper and legitimate use of the English language. There is no lack of rigor in using "weight" in the meaning used in commerce; it is in fact more rigorous that usage in science in general. It is never a force. The mechanics jargon usage, for example, is not the scientific usage in "molecular weight" and the like.

OTOH, saying that an article about acceration is the mechanics version is an extreme case of lack of scientific vigor. Gene Nygaard 15:34, 8 January 2007 (UTC)

"Surface" Gravity of Saturn citation

http://library.thinkquest.org/C001245/OrbitPc.html

Centrifugal Force

I replaced the example of reduced apparent weigh from centrifugal force to the effect of buoyancy. I think this is quite abstract to the casual reader; being immersed on a pool is a experience that everyone can recall. Furthermore, the case of earth rotation is explained in apparent weight, wich is linked. Tercer 23:50, 26 December 2006 (UTC)

Weigh or Weight?

I'm confused, is it weigh or weight? overweigh or overweight? What's the story of those two identical / homophon-homonim words? —The preceding unsigned comment was added by Bennylin (talk • contribs) 18:52, 6 February 2007 (UTC).

The noun is always "weight". And "weigh" is a verb, meaning to have weight or to determine the weight of something; that is often misspelled in Wikipedia articles and elsewhere. However, "weight" can also be a verb, with a different meaning. Try wiktionary:weight and wiktionary:weigh. Gene Nygaard 21:08, 18 February 2007 (UTC)

Irrelevance?

I was reading this article, and it was talking about how weight is used to measure how fat someone was. Then it got off on a tangent about americans, which to me seemed somewhat irrelevant (whether they are or aren't)

Im not suggesting it be removed, but maybe just put in a different place in the article. —The preceding unsigned comment was added by 158.59.229.189 (talk) 16:59, 1 March 2007 (UTC).

Weights of planets (relative or not) irrelevant here?

Shouldn't a list of weights of planets more properly belong in Planets or Solar System? --SV Resolution(Talk) 13:38, 27 July 2007 (UTC)

Should mass versus weight get its own article?

There is currently a discussion about how much detail on the difference between mass and weight should rightfully be in kilogram. If any regular editors are interested in that issue, please comment on the issue in the Request for comments. However, what I really want here is opinions on whether or not there should be a separate article at mass versus weight or if lots and lots of articles pound (mass), kilogram, gram, weighing scale, mass, tonne, ton, ounce and many more should simply link to this article (as many do already). I'm planning on expanding the mass and weight section here if editors don't think it needs its own article.

I can see above that there has been a lot of discussion about how to present the issue of mass versus weight, but I think this is a different issue; should it have its own article, or be here? Enuja 22:02, 20 August 2007 (UTC)

I'd think this is a good place—as long as it isn't built upon a false premise that there necessarily is a "difference between weight and mass".

Both words, of course, are ambiguous words with several different meanings. Often, in many contexts, including the overwhelming majority of articles linked to this one, they mean the same thing. At other times, we need to distinguish between them. What we need here is good information about both cases. Gene Nygaard 16:02, 11 October 2007 (UTC)

Yeah, I'd go along with Gene here. The current article does not appear to acknowledge the existence of the traditional use of the term "weight" to mean "quantity of matter" (that is, mass). That's a defect. --Trovatore 19:21, 21 October 2007 (UTC)

Especially since that's the weight which well over 90% of the incoming links to this article deal with, even though there are also separate articles about various more specific types of weight with that meaning with lots of links of their own. Gene Nygaard 13:25, 22 October 2007 (UTC)

Gene’s arguments are without proper foundation. This article is quite correct. Encyclopedia Britannica very simply defines “weight” as “[the] gravitational force of attraction on an object, caused by the presence of a massive second object, such as the Earth or Moon.” Wikipedia’s Weight article defines weight as follows: In the physical sciences, weight is a measurement of the gravitational force acting on an object. World Book (print edition) says this under Weight: Weight is the gravitational force put forth on an object by the planet on which the object is located. Further, the Kilogram article adheres perfectly to Encyclopedia Britannica’s discussion of the distinction between “weight” and “mass”. The article also gives proper and fair treatment to the fact that the term “weight” in common vernacular can occasionally mean “mass.”

With regard to Encyclopedia Britannica’s article on weight he’s written on Talk:Kilogram that we shouldn’t “stoop” to their level and he’s also written that Wikipedia’s own article on weight, which is linked to in several places in this article can’t be trusted. His attempts to redefine reality are bogus. Greg L (my talk) 16:34, 23 October 2007 (UTC)

I don't think he's trying to "redefine reality", just take note of the fact that the word "weight" has historically often been used, not merely "in the vernacular", to mean "mass". And, in some contexts, continues to be. That's just a true statement about the language; there's no physics content to the dispute. --Trovatore 17:06, 23 October 2007 (UTC)

If he limited himself to just that point, that would be fine. However, he has been active in trying to omit the term “weight” and replace it with “force due to gravity” in Kilogram notwithstanding that “weight” has a clear and unambiguous meaning in the physical sciences, and all other encyclopedic treatments are equally unambiguous. Greg L (my talk) 17:17, 23 October 2007 (UTC)

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This subject is currently being discussed at Talk:Kilogram: Location for “Mass versus weight”. A consensus has been so far achieved that the section Kilogram#Mass versus weight should be moved out of Kilogram. Consideration is being given as to where to move it to. Options are to move it to Mass, or to Weight, or to give it its own article, Mass versus weight that all other articles can link to. If you would like to express an opinion on this matter, please click here. Greg L (my talk) 18:45, 8 November 2007 (UTC)

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• There is now a new article mass versus weight. Discussion on this matter should no longer occur on the kilogram page; discuss it in a new section here or at Talk:Mass versus weight. Enuja (talk) 04:54, 29 November 2007 (UTC)

Slight wording confusion?

It's a very minor point, but should "So, if object A weighs, say, 10 times as much as object B, then object A's mass is 10 times that of object B" actually read "So, if object A has 10 times the mass of object B, then object A's weight will also be 10 times that of object B"

As weight is the factor that is dependent on mass (and gravity) and not the other way around?

138.38.149.112 (talk)

POV-pushing

I just wanted to note that this article, as currently written, pushes a specific, narrow point of view in its opening paragraph. Yes, in the physical sciences, the meaning of weight is generally restricted to a type of force. But in general, weight is a synonym for mass and always has been. The article's focus on a narrow point of view in its first paragraph is inappropriate. --169.236.9.80 (talk) 21:10, 9 April 2009 (UTC)

Agree. The section on measuring weight is getting to the point of being contrived. 'Weight' is a term that has been around in English for centuries; 'mass' only entered the language post-Norman Conquest. Meanwhile, the devices used to measure "weight" (like spring scales, which require precision manufacture) have only been around for about a century and a half at most. By contrast, the mass-measuring devices like the balance scale have been around for millennia. So there's a conundrum: a technology has existed for centuries to measure a concept that was "nameless" in English a millennium ago all the while a term existed for centuries for a concept that has only relatively recently been conceived of, much less ways developed to actually measure it. This ludicrousness is seen in the measuring section: "The standard masses [of a balance] are often referred to, non-technically, as "weights"." And the height of lunacy comes with this sentence: "Some balances can be marked in weight units, but since the weights are calibrated at the factory for standard gravity, the balance will measure standard weight, i.e. what the object would weigh at standard gravity, not the actual local force of gravity on the object." Ah yes, a thousand years ago everyone got their weights from a factory where they were calibrated to standard gravity...

The fact of the matter is that people have been measuring what they called "weight" for centuries and were using a balance scale to do it. The physical sciences today call it mass but back then it was called weight (and still is by most people). The confusion exists because somewhere along the way the concept behind the term 'weight' got changed or modified to mean something it could never have historically meant: a force.

What this and/or the article on mass vs weight needs is an historical overview of it came to be that "weight" ceased to mean mass and came instead to mean a force. Then, and only then, can the weight-mass confusion (sorry) be properly explained. D P J (talk) 18:34, 17 January 2010 (UTC)

Prior to the scientific disentanglement of weight and mass, I imagine that people were aware of the "weight" of something primarily because of the force that gravity exerted on it (as opposed to, for example, what we would now call its intertial mass). Therefore, I don't see any reason to believe that, at any time in history, "weight ceased to mean mass and came instead to mean a force". 86.172.96.114 (talk) 18:11, 25 January 2010 (UTC)

so is it a force or not?

how can it be force, if it is a scalar?

it says: "weight of an object is the magnitude, W, of the force that must be applied to an object in order to support it". —Preceding unsigned comment added by 94.194.101.43 (talk) 17:28, 17 July 2009 (UTC)

Opening definition

Currently the article says:

"The weight of an object in static equilibrium equals the magnitude of the gravitational force acting on the object, less the effect of its buoyancy in any fluid in which it might be immersed."

Should this also be less the (latitude-dependent) centrifugal force resulting from the Earth's rotation? 86.134.43.54 (talk) 00:37, 24 January 2010 (UTC)

No - the effects of the centrifugal force have already been taken into account by the earth being an ellipsoid rather than a sphere - as a result the gravitational force varies on the Earth - it is about 0.5% higher at the Poles than the Equator. Martinvl (talk) 07:29, 24 January 2010 (UTC)

No, that's a different effect. There are two things going on here: the ellipsoidal shape of the earth, which actually makes the gravitational force less, and the centrifugal force that diminishes the apparent effect of the gravitational force that is exerted. 86.161.42.192 (talk) 14:31, 24 January 2010 (UTC).

We could replace the words "gravitational force" by the words "measured gravitational force". This will take into account centrifugal forces as it will lump all the forces acting on the obejct apart from bouyancy into a single force.. —Preceding unsigned comment added by Martinvl (talk • contribs) 15:21, 24 January 2010 (UTC)

I'm not keen on that. There seems no reason why "measured gravitational force" wouldn't also take into account buoyancy. 86.134.13.125 (talk) 23:49, 24 January 2010 (UTC)

OK then, "gravitational force as measured in a vaccuum". In the case of a body with a density of 1000 kg/m³, then by Archimedes Principle, the buoyancy due to air reduces its apparent weight by about 0.1%, air having a density of about 1.2 kg/m³. Put the same body intowater andit will lose all of its apparent weight (ie it will float). Martinvl (talk) 06:32, 25 January 2010 (UTC)

The "true" gravitational force acting on a body is identical whether it is in a vacuum, in air, or in any other fluid, so the term "gravitational force" in "gravitational force as measured in a vaccuum" presumably actually means "weight force". Thus, by using this wording, we would effectively be saying "The weight of an object equals its weight in a vacuum less the effect of its buoyancy in any fluid in which it might be immersed." which is probably not what we want. 86.140.131.81 (talk) 14:47, 25 January 2010 (UTC).

"Weight" and "Apparent weight": Contradiction and Confusion

This article says that "weight" is lessened by the effect of buoyancy. This contradicts Apparent weight, where "weight" is said to be purely the gravitational force (i.e. excluding things such as buoyancy). We need some experts to focus their attention on these two articles and decide, of all the forces and accelerations acting on a body in a gravitational field (in particular a body at the surface of the Earth), which contribute to the object's "weight" and which do not. As well as gravitational force, these include:

• Buoyancy (in air or other fluid). For example, what is the weight of a helium balloon? What is the weight of a floating piece of wood?
• Centrifugal force (on spinning Earth).
• The effect of accelerations, such as in a lift. For example, consider astronauts in orbit. What is their weight? If it's zero then this implies that the weight of someone in a free-falling lift is zero, and that their weight in a lift accelerating downwards at 0.5g is half their normal weight, which undermines most of the supposed distinction at Apparent weight.
• Any other miscellaneous forces, such as magnetism.

The factors that do not contribute to "weight" presumably explain the difference between "weight" and "apparent weight". If all the forces and accelerations acting on a body contribute to "weight" then presumably "apparent weight" is a bogus concept. 86.136.27.202 (talk) 21:03, 2 February 2010 (UTC).