What Is the Lightest Weight Measurable by a Sensitive Scales?

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Discussion Overview

The discussion revolves around the concept of the lightest weight measurable by sensitive scales, exploring the relationship between mass and weight, and the theoretical limits of mass in nature. Participants delve into various particles, including neutrinos and Planck mass, while addressing the implications of measuring extremely small weights.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that everything with mass has weight, using examples like a bread crumb.
  • Others propose that the neutrino may have the smallest mass, although this is questioned by some who seek clarification on the smallest measurable mass.
  • Several participants mention the Planck mass (2.176 × 10-8 kg) as the smallest mass that can exist in nature, but express uncertainty about what has that mass.
  • There is a discussion about the distinction between weight and mass, with some arguing that weight is dependent on gravitational force.
  • Some participants challenge the idea of a lower limit to mass, suggesting that it may be possible to divide matter indefinitely.
  • One participant mentions that photons are considered to have zero mass, raising questions about the nature of mass and weight.
  • There is a debate about the Planck length and its implications for measuring mass and distance, with some participants expressing confusion about its definition and application.
  • Some participants express skepticism about the clarity of definitions related to Planck units and their implications for physical measurements.

Areas of Agreement / Disagreement

The discussion contains multiple competing views regarding the smallest mass and the relationship between mass and weight. There is no consensus on whether the Planck mass is the smallest mass possible or if there are smaller measurable entities.

Contextual Notes

Participants express uncertainty about the definitions of mass and weight, and the implications of Planck units. There are unresolved questions regarding the smallest measurable mass and the nature of particles like neutrinos and photons.

Who May Find This Useful

This discussion may be of interest to those exploring concepts in physics related to mass, weight, and the fundamental limits of measurement in theoretical physics.

scupydog
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Scupydog is my dad i would like to ask a question that my dad thinks he can answer.

If you had a very sensitive weighing scales and you put the lightest thing on them, what would it weigh.

Daisy 11. :smile:
 
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Everything that is matter has mass. A bread crumb has a weight.
 
Werg22 said:
Everything that is matter has mass. A bread crumb has a weight.

What would have the smallest mass.
 
To my knowledge, an elementary particle called the neutrino has the smallest mass. I could be wrong, however.
 
The smallest mass that can exist in nature is 2.176 × 10-8 kg which is the Planck mass. I don't know what has that mass though..
 
Weight is a force, it depends on the mass of thing you're weighing and the acceleration due to gravity where you are. weight=mass*gravity

Basically you weigh more when gravity is stronger, gravity is about the same everywhere on the surface of the Earth, but actually it's slightly stronger at the poles - if you went to the North Pole you'd weigh more than if you were on the equator!
 
He meant mass, so weight doesn't have much to do with this.

Either way you see it, the lightest thing would be the thing with the smallest mass, if you compare it to something with the same gravitational force on it...
 
Jarle said:
The smallest mass that can exist in nature is 2.176 × 10-8 kg which is the Planck mass. I don't know what has that mass though..

My dad said the same thing.:smile:
 
Yes I did, son.


:P
 
  • #10
Jarle said:
Yes I did, son.


:P

Daisy is an odd name for a son :)
 
  • #11
Oh, it's a girl. Oh well, my lie has been revealed.
 
  • #12
Werg22 said:
To my knowledge, an elementary particle called the neutrino has the smallest mass. I could be wrong, however.
I don't that what she's asking. That would the wo..universe's lightest object but not the smallest mass possible. I don't know if there's a limit to how small things could get.
 
  • #13
Yes there is, and it is restricted to the Planck length as far as I know. The smallest 'amount' of mass that can be set in the smallest possible volume (planckmeter^3) is excactly the Planckmass.

If you are talking about weight, the smallest theoretical possible weight is 0, if not other mass is affecting the object, or is affecting it equally on all sides.
But weight is not the question here, because it differs.
 
  • #14
scupydog said:
My dad said the same thing.:smile:
The electron, which is certainly NOT the lightest particle of matter in the universe, is nearly a million million millon million times lighter than anything that might have Planck mass.

This may give you some idea: http://en.wikipedia.org/wiki/Orders_of_magnitude_(mass)
Werg22 said:
To my knowledge, an elementary particle called the neutrino has the smallest mass. I could be wrong, however.

The last time I stood on a weighing scale, it showed a little more than a few eV. :-p
 
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  • #15
Jarle said:
The smallest mass that can exist in nature is 2.176 × 10-8 kg which is the Planck mass.
How is it then, that this is roughly the mass of one of my hairs? I can name a lot of things that are lighter than this.

daisy said:
My dad said the same thing.
Even dads can be wrong every once in a while. Most of the time, they're right though!
 
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  • #16
Gokul43201 said:
How is it then, that this is roughly the mass of one of my hairs? I can name a lot of things that are lighter than this.


Even dads can be wrong every once in a while. Most of the time, they're right though!

Haha, there was a time were I took my dad for a textbook. The innocence of childhood... :-p
 
  • #17
Gokul43201 said:
How is it then, that this is roughly the mass of one of my hairs? I can name a lot of things that are lighter than this.

You tell me! :bugeye:

I thought the Planck units were the smallest units you could use, and that exists...
 
  • #18
Why don't you look up what Planck mass means and how it is defined?
 
  • #19
I did, I read an article about it... I'll look up on it again...
 
  • #20
no offense but this question has no meaning of course it would find the wieght if it was SENSITIVE ENOUGH! if not it would'nt register anythinf
 
  • #21
you'd probably need a cyclotron or something in that high-energy category to even detect its presence, let alone measure it
 
  • #22
Well, the weight was supposed to measure it's WEIGHT, not it's amount of energy, right?

I read about Plancks constant, didn't udnerstand a thing, wikipedia is so unclear on definitions.

What IS the smallest weight then?
 
  • #23
Jarle said:
What IS the smallest weight then?

There is none, AFAIK. There might be a particle* which has the smallest measured mass (let's avoid weight), but if you're looking for an absolute lower limit (greater than 0) set by nature, I don't think there is one. Someone correct me if I'm wrong.

*most probably a neutrino, as of now
 
  • #24
I really was convinced that this lower limit was the Planck mass.

I find it hard to believe that you could cut material in half endlessly and never get to the point where you can't cut no more.
 
  • #25
Jarle said:
I read about Plancks constant, didn't udnerstand a thing, wikipedia is so unclear on definitions.

Here is the wiki article on the Planck Mass: http://en.wikipedia.org/wiki/Planck_mass.

I think the definition here is quite clear.
 
  • #26
You can't actually weigh a photon but I suppose they have as small a mass as is conceivable - zero.
 
  • #27
cristo said:
Here is the wiki article on the Planck Mass: http://en.wikipedia.org/wiki/Planck_mass.

I think the definition here is quite clear.

if i get three pieces of string of Planck length and form them into a circle then the diameter is less than the Planck length
 
  • #28
scupydog said:
if i get three pieces of string of Planck length and form them into a circle then the diameter is less than the Planck length

What do you intend to make these pieces of string out of? The Planck length is of the order 10-35m, whereas the radius of an atom is of the order 10-13m.
 
  • #29
cristo said:
Here is the wiki article on the Planck Mass: http://en.wikipedia.org/wiki/Planck_mass.

I think the definition here is quite clear.

cristo said:
What do you intend to make these pieces of string out of? The Planck length is of the order 10-35m, whereas the radius of an atom is of the order 10-13m.
so the Planck length has to be a circumferance because it can't be a radius or must it be a radius
 
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  • #30
As for the wiki article mentioned, I would not say that the Planck mass is the smallest mass possible. It is the mass of a particular type of black hole whose radius is 'roughly' the Planck length. It might result that it is the densest mass possible (just a wild guess).
 

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