0
$\begingroup$

Picture of small metal disks slotted onto as hook, such as could be attached to a spring to study Hooke's law

Yeah, those circular metal disks. Weights or masses? I call them weights because when I attach them to a spring I'm interested in their weight, but it feels odd saying a "Pick up the 100g weight". "Pick up the weight with a mass of 100g sounds better" but it still feels wrong.

I don't like to call them masses, because I've never heard anyone else call them masses, unless it's someone trying to correct me for making the 'mistake'.

$\endgroup$

closed as off-topic by Qmechanic Sep 24 '15 at 18:11

  • This question does not appear to be about physics within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ possibly relevant: physics.stackexchange.com/a/138296/26969 $\endgroup$ – Floris Sep 24 '15 at 17:24
  • $\begingroup$ @Floris Did you downvote? Could you tell me how to improve my question? $\endgroup$ – Jamie Twells Sep 24 '15 at 17:25
  • $\begingroup$ No I didn't. I almost always leave a comment explaining a downvote. $\endgroup$ – Floris Sep 24 '15 at 17:27
  • 1
    $\begingroup$ @Floris Ok thanks. I don't want to post bad questions but I wouldn't be able to change if I wasn't told why my question was bad. Thanks for the answer. I know the difference between mass and weight, so your linked answer isn't really useful to me. I just want to know which term is correct. It's difficult to search for because there are millions of results for "weight vs mass" not many for "weights vs masses" and I'm about to start teaching Physics in high school, so I don't want to use an incorrect term. $\endgroup$ – Jamie Twells Sep 24 '15 at 17:30
  • $\begingroup$ I'm voting to close this question as off-topic, cf. e.g. this meta post. $\endgroup$ – Qmechanic Sep 24 '15 at 18:11
3
$\begingroup$

It is absolutely fine to call these objects "weights", since you are interested in their weight - i.e. the force of gravity on them. You are not using them for their inertial properties.

Dictionary definition of weight: (Dictionary.com - definition 5)

a body of determinate mass, as of metal, for using on a balance or scale in weighing objects, substances, etc.

NB - this definition makes it explicit that a weight has mass. In other words - while you call it a weight (the object), the physical property is mass (100 gram). Which, at a particular point on earth, translates into a weight.

$\endgroup$
  • 2
    $\begingroup$ Your first paragraph puts it very elegantly :-) $\endgroup$ – John Rennie Sep 24 '15 at 17:34
  • $\begingroup$ "You are not using them for their inertial properties." Depends. When I have my students do the "mass-on-a-spring" oscillation experiment is it exactly their inertial properties that matter. /*::snark::* $\endgroup$ – dmckee Oct 24 '15 at 18:33
  • 1
    $\begingroup$ @dmckee OP explicitly said he was interested in their weight - and that is the "you" in my statement. I will leave it up to the intelligent reader to infer that I would not advocate calling them weights in an inertial context. $\endgroup$ – Floris Oct 24 '15 at 20:49
1
$\begingroup$

So, even though they are measured in grams (which you correctly assessed as a unit of mass), it is quite all right to call these objects weights. That is because the word weight can refer to the force of mass times acceleration due to gravity or "a body of determinate mass." (dictionary.com)

$\endgroup$
0
$\begingroup$

If you pick up a weight and bring it some other place, then the weight at that other location will not be exactly the same. Wat happened to the difference between the initial weight and the final weight? Because weight it is not conserved, nothing needs to have happened. If you had instead said that you picked up a mass and brought that mass to that other location, then because the mass would be the same, you would avoid this ambiguity.

So, it's better to refer to mass instead of weight, but it does come at the risk of making you look like this guy:

enter image description here

$\endgroup$
  • $\begingroup$ Hi. I'm not sure you've understood my question. Or perhaps I don't understand your answer. $\endgroup$ – Jamie Twells Sep 24 '15 at 18:03

Not the answer you're looking for? Browse other questions tagged or ask your own question.