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Re: What is mass?

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Mahipal wrote:

> On Monday, September 28, 2015 at 2:13:19 AM UTC-4, Yousuf Khan wrote:
>> On 23/09/2015 12:02 PM, gilber34 wrote:
>> > I now understand that mass is only defined by its effects, so I realize
>> > that my biggest problem is related to quantification. I don't
>> > understand how people came up with a system to quantify mass.

From Newton’s «Philosophiæ Naturalis Principia Mathematica» (1686):

«Def. I.

Quantitas Materiæ est mensura ejusdem orta ex illius Densitate & Magnitudine 
conjunctim.

Aer duplo densior in duplo spatio quadruplus est. Idem intellige de Nive et 
Pulveribus per compressionem vel liquefactionem condensatis. Et par est 
ratio corporum omnium, quæ per causas quascunq; diversimode condensantur. 
Medii interea, si quod fuerit, interstitia partium libere pervadentis, hic 
nullam rationem habeo. Hanc autem quantitatem sub nomine corporis vel Massæ 
in sequentibus passim intelligo. Innotescit ea per corporis cujusq; pondus. 
Nam ponderi proportionalem esse reperi per experimenta pendulorum 
accuratissime instituta, uti posthac docebitur.»

Which Motte (1729) translated to:

“Def. I.

The Quantity of Matter is the measure of the same, arising from its density 
and bulk conjunctly.

THUS AIR of a double density, in a double space, is quadruple in quantity; 
in a triple space, sextuple in quantity. The same thing is to be understood 
of snow, and fine dust or powders, that are condensed by compression or 
liquefaction; and of all bodies that are by any causes whatever differently 
condensed. I have no regard in this place to a medium, if any such there is, 
that freely pervades the interstices between the parts of bodies. It is this 
quantity that I mean hereafter everywhere under the name of Body or Mass. 
And the same is known by the weight of each body, for it is proportional to 
the weight, as I have found by experiments on pendulums, very accurately 
made, which shall be shewn [sic] hereafter.”

<https://en.wikipedia.org/wiki/Philosophi%C3%A6_Naturalis_Principia_Mathematica#External_links>

>> > I tried to figure it out using the formula for mass, which is F= m . a
>> > and my issue was the following: a: Acceleration as a concept is very
>> > straightforward.
>> 
>> I'm going to go about this from a different angle, a more modern point
>> of view. That is Einstein's Special Relativity:
>> 
>> E = m * c^2
>> 
>> or, more appropriately:
>> 
>> m = E / c^2
>> 
>> Why am I going from this Relativistic point of view, rather than the
>> more traditional Newtonian point of view? And what difference does it
>> make if you go from one POV or the other? The reason is that Einstein's
>> POV actually tells you where mass comes from and how it is created,
>> whereas Newton's doesn't, all Newton's does is it tells you what happens
>> to a mass when you apply a force to it.

ACK.
 
> Regardless of Newton, your equation above is not due to Einstein.

Yes, it *is* (due to [*because of*] Einstein).  From “Ist die Trägheit eines 
Körpers von seinem Energieinhalt abhängig?“ (1905; “Does the inertia of a 
body depend upon its energy content?”):

„[…]
Aus dieser Gleichung folgt unmittelbar:
  Gibt ein Körper die Energie L in Form von Strahlung ab, so verkleinert 
sich seine Masse um L∕V². […]“

Whereas Einstein still used “V” for the speed of light (from /velocitas/).
Which in the book “The Principle of Relativity” (1923) is translated to:

“[…]
From this equation it directly follows that:—
  If a body gives off the energy L in the form of radiation, its mass 
diminishes by L/c². […]”

That uses the then-adopted standard of “c“ as symbol for the speed of light.

> Do your history homework before you project your brainwashing.

Do yours.  Einstein has not written the equation (this way), but, as you can 
see above, he was the first to formulate the idea of mass–energy 
equivalence.  (This is an interesting historic fact because Newton did not 
explicitly write “F = m a” either, but initially he used words to describe 
motion, the same as Aristotle before.  [Only that Aristotle’s got it 
wrong.])

<https://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence#Nomenclature>
<https://de.wikipedia.org/wiki/%C3%84quivalenz_von_Masse_und_Energie#Zeittafel>

> E=hf per Planck, the true unsung hero of QM.

Hardly.  AFAIK, Planck was the one who first used “c” as symbol for the 
speed of light in vacuum, writing down the mass–energy equivalence as

  M = (E₀ + p V₀)/c²

where p is pressure and V₀ is volume, in 1907.

And *quanta* (not: QM – Quantum Mechanics) were just an idea of Planck’s at 
the time; the idea gained acceptance and *later* there was QM because 
Einstein used Planck’s idea, including E = ℎf, to explain the photoelectric 
effect in 1905 (for which Einstein was awarded the Nobel Prize in Physics 
1921; and Einstein has given him due credit in his work, so there really is 
nothing for you to complain about).  In fact, Einstein assumed quanticized 
*light*, an idea that Planck was *opposed to* at the time.

That is not to say that someone else could not have done it later (several 
scientists were working on the problem), but Einstein was the one who did 
it.  So if you are an admirer of Planck’s, you better show a little respect 
for Einstein as well.

Finally, it turns out that the energy–momentum relation of (Einstein’s) 
special relativity, derived from the norm of the four-momentum in Minkowski 
space(time),

  E² = (pc)² + (mc²)²

when solved for energy E,

   E = √((pc)² + (mc²)²),

beautifully reduces to

   E = pc

for photons with assumed mass m = 0, which, because of Planck’s relation of 
momentum

   p = ℎf∕c,

gives

   E = ℎf∕c × c

and therefore Planck’s

   E = ℎf.

>> So what this means is that you can use the same units to describe mass
>> as you can use to measure Energy. So one unit of energy is the "eV"
>> (electron-volt), used in particle physics, rather than the Joule; the
>> associated mass unit is eV/c^2 (electron-volt per light-speed squared).
>> The eV/c^2 is often just shortened down to eV because c^2 is a constant.
>> You can even convert the kg to an eV/c^2:
>> 
>> 1 kg = 5.609589×10^35 eV/c^2
> 
> There are far more measurement systems than are dreamt of in your domain.

That is a funny reply, but this is not a measurement system, it is the 
definition of a unit of mass.  And this unit is particularly useful indeed, 
because it allows us to increase charged particles’ (e.g., protons’) 
energies by accelerating them (and we can calculate how fast they need to go 
to carry a certain energy, so we know how fast to switch the electromagnets 
accelerating them), and then creating particles with rather huge, but 
assumed distinct, masses, like Higgs bosons (one with a mass of 125 GeV∕c²), 
by having those accelerated particles collide with one another.

<http://home.web.cern.ch/about/accelerators>
  
>> So what does this weird value of the kilogram, tell us about the
>> kilogram? It just means that the kilogram is just an arbitrary unit that
>> was created at a time when we weren't measuring individual atoms, but
>> bulk items of daily practical value. The original definition of the
>> kilogram was 1 cubic meter of water is equal to 1 kg, at room
>> temperature at standard atmospheric pressure.

It was (and is) effectively one litre (1 cubic _decimetre_) of water, the 
specified temperature was lower (ca. 4 °C, not ca. 20 °C), and there was no 
statement as to the pressure (so “standard atmospheric pressure” is implied 
only).  Everything else is correct ;-)

>> So if you expect the kg to be related to a specific rounded number of
>> atoms of something, then you can forget it, it wasn't the purpose of the
>> kg when it was created.
> 
> One cubic meter of water? Seriously?

His number is off by a factor of 1000, and there are a few inaccuracies, but 
otherwise it was indeed decreed in France, 1795:

« 5. Les nouvelles mesures seront distinguées dorénavant par le surnom de 
républicaines; leur nomenclature est définitivement adoptée comme il suit:  
On appellera: Mètre, la mesure de longueur égale à la dix-millionième partie 
de l'arc du méridien terrestre compris entre le pôle boréal et l'équateur.  
[…]
Gramme, le poids absolu d'un volume d'eau pure égal au cube de la centième 
partie du mètre , et à la température de la glace fondante.
[…] »

Which, according to Google Translate and me, translates to:

“5. The new measures will now be distinguished by the additional name 
‘Republican’; their nomenclature is definitively adopted as follows:  
We will call: metre, the measurement of length equal to the ten millionth 
part of the terrestrial meridian arc between the North Pole and the equator. 
[…]
Gram, the absolute weight of a volume of pure water equal to the cube of the 
hundredth part of the meter [one cubic centimetre; the tr.], and at the 
temperature of melting ice.
[…]”

From that, because the kilogram (1'000 grams) proved to be more practical in 
everyday life, an all-platinum kilogram prototype was made in 1799; it 
served as standard until 1889.

<https://en.wikipedia.org/wiki/Kilogram#Kilogramme_des_Archives> p.

> Can you Yousuf lift 1kg of one cubic meter of ...as you say... water?

If it is confined, and given a long enough lever ;-), certainly everyone 
can.  And we can measure the mass of the confinement, say a barrel, 
separately.  So subtract that from the mass of what you are lifting 
(confinement + water), you get the mass of the water you would be lifting.

>> When we originally started creating units of measurement, they were
>> based on human-scale requirements. […]
> 
> Who is this we We WE

Humanity.  Now that was easy.

See also one of my earlier articles on the subject:

<news:8576732.FFMuFSN7Ay@PointedEars.de>


PointedEars
-- 
Q: What did the female magnet say to the male magnet?  
A: From the back, I found you repulsive, but from the front
   I find myself very attracted to you.
(from: WolframAlpha)

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Thread

What is mass? gilber34 <fafa@invalid.com> - 2015-09-23 11:02 -0500
  Re: What is mass? Poutnik <Poutnik4NNTP@gmail.com> - 2015-09-23 18:55 +0200
  Re: What is mass? Fabian Russell <root@localhost.localdomain> - 2015-09-23 16:59 +0000
    Re: What is mass? Poutnik <Poutnik4NNTP@gmail.com> - 2015-09-23 19:12 +0200
      Re: What is mass? Poutnik <Poutnik4NNTP@gmail.com> - 2015-09-23 19:17 +0200
      Re: What is mass? Fabian Russell <root@localhost.localdomain> - 2015-09-23 17:34 +0000
        Re: What is mass? Poutnik <poutnik4nntp@gmail.com> - 2015-09-23 20:35 +0200
          Re: What is mass? omnilobe@gmail.com - 2015-09-23 12:40 -0700
          Re: What is mass? Fabian Russell <root@localhost.localdomain> - 2015-09-23 21:44 +0000
            Re: What is mass? Poutnik <poutnik4nntp@gmail.com> - 2015-09-24 08:50 +0200
              Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-26 22:34 -0700
        Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-26 08:35 +0200
          Re: What is mass? Fabian Russell <root@localhost.localdomain> - 2015-09-26 12:35 +0000
            Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-26 15:37 +0200
              Re: What is mass? john <johnsefton288@gmail.com> - 2015-09-26 07:14 -0700
                Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-26 16:17 +0200
          a-hem; m = F/a is also gOOd noTthaTguY <abu.kuanysh05@gmail.com> - 2015-09-26 17:16 -0700
            Re: a-hem; m = F/a is also gOOd Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-27 03:26 +0200
              top-posting is frpowned upon by certain advertizers ... just don't ask them, why not noTthaTguY <abu.kuanysh05@gmail.com> - 2015-09-27 15:53 -0700
                What is mass (was: top-posting is frpowned upon by certain advertizers ... just don't ask them, why not) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-28 17:05 +0200
                a.k.a photonics -- thanks for the tip (pi dollars is gOOd noTthaTguY <abu.kuanysh05@gmail.com> - 2015-09-29 11:28 -0700
                Re: a.k.a photonics -- thanks for the tip (pi dollars is gOOd Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 21:01 +0200
                no skwares in the medium of space noTthaTguY <abu.kuanysh05@gmail.com> - 2015-09-29 19:29 -0700
    Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-23 23:07 -0700
  Re: What is mass? "nuny@bid.nes" <Alien8752@gmail.com> - 2015-09-23 14:01 -0700
    Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-27 23:40 -0700
  Re: What is mass? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-09-24 13:36 -0700
  Re: What is mass? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2015-09-28 02:13 -0400
    Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-28 09:27 -0700
      Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 04:31 +0200
        Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-29 00:29 -0700
          Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 13:21 +0200
            Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 13:34 +0200
            Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-29 05:19 -0700
        Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 05:40 -0700
          Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 15:11 +0200
            Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 06:37 -0700
              Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 16:22 +0200
                Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 07:51 -0700
                Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 18:45 +0200
                Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 11:06 -0700
                Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 21:00 +0200
                Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 13:47 -0700
                Re: What is mass? "Ma Hipple" <invalid@example.com> - 2015-09-30 07:20 -0700
              Re: What is mass? "Alan Smith" <invalid@example.com> - 2015-09-29 07:33 -0700
          Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-30 02:21 -0700
            Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-04 19:11 -0700
              Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-10-05 00:39 -0700
                Re: What is mass? noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-05 18:38 -0700
                Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-05 18:50 -0700
                Re: What is mass? "Eric Smith" <invalid@example.com> - 2015-10-05 20:01 -0700
                Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-05 20:49 -0700
                Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-10-06 03:18 -0700
              Re: What is mass? "Fred Smith" <invalid@example.com> - 2015-10-06 17:41 -0700
                Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-06 19:38 -0700
                Re: What is mass? "Greg Smith" <invalid@example.com> - 2015-10-07 06:59 -0700
                Re: What is mass? gilber34 <fafa@invalid.com> - 2015-10-07 09:03 -0500
                Re: What is mass? "Hank Smith" <invalid@example.com> - 2015-10-07 07:20 -0700
                Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-07 08:11 -0700
                Re: What is mass? noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-07 16:07 -0700
                Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-10-08 00:18 -0700
                Re: What is mass? john <johnsefton288@gmail.com> - 2015-10-08 06:15 -0700
                Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-10-10 01:11 -0700
                Re: What is mass? noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-10 16:43 -0700
                Re: What is mass? noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-08 12:34 -0700

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