Grab a bag of sugar and say this weighs 1KG

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Discussion Overview

The discussion revolves around the distinction between mass and weight, particularly in the context of everyday language and scientific terminology. Participants explore the implications of using "weight" colloquially to refer to mass and the legal and scientific definitions of these terms. The conversation touches on the nuances of measurement and the impact of language on understanding physical concepts.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Meta-discussion

Main Points Raised

  • Some participants assert that kilograms (kg) are a unit of mass, while weight is measured in newtons (N), with the weight of 1 kg on Earth being approximately 9.81 N.
  • Others argue that in everyday language, "weight" is often used synonymously with mass, which can lead to confusion.
  • A participant points out that weight can vary based on location due to differences in gravitational acceleration, citing specific examples from Mexico City and Oslo.
  • There is a suggestion that when people refer to weight in kilograms, they are actually using a unit of mass, not weight.
  • Some participants discuss the concept of "kilograms force" (KgF) as a way to describe the weight of a mass under standard gravity.
  • A later reply emphasizes that many words, including "weight," have multiple meanings and that arguing about their usage can be counterproductive.
  • Another participant expresses a personal opinion that scientists may be wrong in their strict definitions, drawing a parallel to how the lay community uses the term "theory." They suggest that scientists should not impose their terminology on the lay community.

Areas of Agreement / Disagreement

Participants generally disagree on the implications of using "weight" versus "mass" in colloquial language. While some maintain that the scientific definitions should be upheld, others argue for the acceptance of common usage. The discussion remains unresolved regarding the appropriateness of these terms in different contexts.

Contextual Notes

There are limitations regarding the assumptions made about the definitions of weight and mass, as well as the varying interpretations of these terms in legal and colloquial contexts. The discussion does not resolve the mathematical or conceptual nuances involved.

MrPickle
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If I were to grab a bag of sugar and say this weighs 1KG. What do I actually mean?

KG is the unit for mass, not weight. What is the actual weight of the bag of sugar? (Assuming I'm on earth) Would it be 9.81N?

This has been running through my mind recently, I want to try and put the common world into it's proper perspective.
 
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MrPickle said:
If I were to grab a bag of sugar and say this weighs 1KG. What do I actually mean?

KG is the unit for mass, not weight. What is the actual weight of the bag of sugar? (Assuming I'm on earth) Would it be 9.81N?

This has been running through my mind recently, I want to try and put the common world into it's proper perspective.

You are right mass and weight are different things and on Earth every Kg weighs 9.81N.
 


Dadface said:
You are right mass and weight are different things
There are not different things colloquially, and more importantly, they are not different things legally. You have to be careful here. Weight has multiple meanings. A synonym for mass is one of them.

and on Earth every Kg weighs 9.81N.
And that is simply not true. A kilogram has a scale weight of 9.779 Newtons in Mexico City but 9.819 Newtons in Oslo. That is exactly why legally weight is a synonym for mass.
 


So when a "common" person refers to weight they actually mean mass and it's the word that's incorrectly used, not the unit?
 


MrPickle said:
So when a "common" person refers to weight they actually mean mass and it's the word that's incorrectly used, not the unit?

Well when people say weight in kilos, they are using the unit of mass.

However! You can describe weight as "kilograms force". Which is descirbing the weight that 1 kilogram of mass would make in standard gravity.

1 KgF = 9.81 N = 1kg mass * gravity
Its only the same as imperial units. Lbs for mass and lbf for force.

1 lbf is the force given by a 1 lb weight * gravity.
 


The word is fine. Many words have multiple meanings. Suppose you pick an argument with a lay person regarding their supposed incorrect use of the the word "weight". One of the two of you is indeed wrong: You.
 


D H said:
The word is fine. Many words have multiple meanings. Suppose you pick an argument with a lay person regarding their supposed incorrect use of the the word "weight". One of the two of you is indeed wrong: You.

But it is scientifically wrong, isn't it?
 


MrPickle said:
But it is scientifically wrong, isn't it?

My personal opinion: In this case it is the scientists that are wrong. Look at it this way: Scientists really, really do not like the way the lay community has contorted the meaning of the word "theory". A scientific theory is the gold standard of science. You can't get any better. Somehow, theory has been contorted to mean "wild-assed guess" in the lay community -- and the lay community uses this meaning to question science. For example, "Evolution is only a theory, isn't it?"

If we want to get uppity about the lay community usurping our terms, we ought not to usurp theirs. If we do, we ought not to get uppity about the lay community continuing to use their terms in the way they have used them for a long, long time.
 

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