THE
FOUR LAWS
WITHOUT
WHICH NOTHING WHATSOEVER
THROUGHOUT
THE UNIVERSE THAT HAPPENS,
HAPPENS.
These Laws are,
of course – you guessed it – the Laws of Thermodynamics, of which the First,
Second and Third are familiar, when best remembered in the words of C P Snow:
First Law: You cannot win,
that is, you cannot get
something for nothing, because matter and energy are conserved.
Second Law: You
cannot break even,
meaning that you cannot
return to the same energy state, because there is always an increase in
disorder; entropy always increases.
Third Law: You
cannot get out of the game,
because absolute
zero is unattainable.
So far it
sufficed to know (at least among laymen like me) that this ‘absolute zero’ is
zero K (the zero point in the Kelvin scale of temperature, or -273.15 °C in the
familiar Celsius scale). Peter Atkins in his book (shown illustrated in
slide [A] below) relates the need for another law to describe the term
‘temperature’ in these words:
“Classical
thermodynamics is the part of thermodynamics that emerged during the
nineteenth century before everyone was fully convinced about the reality of
atoms, and concerns relationships between bulk properties. You can do classical
thermodynamics even if you don’t believe in atoms. Towards the end of the
nineteenths century, when most scientists accepted that atoms are real and not
just an accounting device, there emerged the version of thermodynamics called statistical
thermodynamics, which sought to account for the bulk property of matter in
terms of its constituent atoms…
“In short, whereas
dynamics deals with the behaviour of individual bodies, thermodynamics
deals with the average behaviour of vast numbers of them…
“Speaking about the
‘inside’ of a system, its structure of atoms and molecules, is alien to classical
thermodynamics, but it adds deep insight, and science is all about insight.”
And therefore
the need for the Zeroth Law -- zeroth, because the existing three laws of
thermodynamics
“… are so well established
that there was no hope of going back and renumbering them. As
will become apparent, each law provides an experimental
foundation for the introduction of a thermodynamic property. The zeroth law
establishes the meaning of what is perhaps the most familiar but is in fact the
most enigmatic of these properties: temperature.”
Zeroth Law: If A is in thermal
equilibrium with B, and B is in thermal equilibrium with C, then C will be in
thermal equilibrium with A.
“The zeroth law implies
that just as the pressure is a physical property that enables us to anticipate
when systems will be in mechanical equilibrium when brought together regardless
of their composition and size, then there exists a property that enables us to
anticipate when two systems will be in thermal equilibrium regardless of their
composition and size: we call this universal property the temperature…
“The zeroth law is the
basis of the existence of a thermometer, a device for measuring
temperature. A thermometer is just a special case of the system B that we talked about earlier.”
Slide [A]
A footnote
regarding the reporting of energy is also given by Atkins, and I think worth
quoting here:
“Energy is reported in joules (J): 1 J = 1 kg m2 s-2. We
could think of 1J as the energy of a 2 kg ball travelling at 1 m s-1. Each pulse of the human heart expends an
energy of about 1 J.”
Shortly after I
had prepared Slide [A] for a talk, I paid a short visit to Munich where I was
dumbfounded by seeing what I meanwhile made into Slide [B], as part of an
exhibition simply entitled RUMFORD (Count Rumford, Benjamin Thompson, 1753 –
1814). This exhibition covered many aspects
of life and work of this cosmopolitan multi-talent, equally at home in Boston,
Munich, London (Fellowship of the Royal Society, 1781; founder of the Royal
Institution) and Paris.
One of the
displays on show was a scale model of his horse powered experiment to help
clarify the relationship between energy, work and heat quantity. An exhaustive and beautifully presented 370-page
Quarto format book [RUMFORD, Rezepte für ein besseres Bayern (RUMFORD, recipes
for a better Bavaria), Münchner Stadtmuseum & Hirmer Verlag GmbH, Munich,
2014; author: Thomas Weidner], accompanied the exhibition, from which the
illustration in my talk slide [B] is taken.
Slide [B]
Let me quote
this excerpt from the start of Thomas Weidner’s account of this of Count
Rumford’s many experiments (my translation):
“From this best known of
Rumford’s experiments he derived a proof that heat is a form of
energy-in-motion which is still valid today. His researches brought a
long-running dispute to end; it had started with the hypothesis that heat
should be classified as a form of matter. This substance made the rounds at the
time under names like ‘Caloricum’ or ‘Phlogiston’ in learned discussions. A
leading proponent, among others, of this ‘caloric’ theory of heat was the
chemist Antoine Laurent de Lavoisier (1743 – 1794) who believed that this
proposed heat fluidum could be regarded as one of the chemical elements. It is
one of history’s curiosa, that Rumford later married Lavoisier’s widow.
With this demonstration of
the kinetic definition of heat, Rumford was instrumental in helping the
opposite view to become the winner in this dispute. It was a fundamental
concept underlying the development of industrialisation during the 19th
century….”
Having been
primed by Peter Atkins’ description and definition of the Zeroth Law of
Thermodynamics before seeing this RUMFORD exhibition and then also reading
Thomas Weidner’s detailed account of Rumford’s experimental setup and account
of his meticulous records of thermometer readings, the thought occurred to me
that this experiment could well be termed the Birth of Thermodynamics with this
model as iconic reminder.
Rumford
presented his experiment to the Royal Society in London on25 January 1798 under
the title
An
Experimental Inquiry concerning the Source of Heat which is Excited by
Friction. I found it
published as one of nine other of Rumford’s presentations in the collection by
Sanborn C Brown:
Pergamon Press First Edition 1967
Rumford
concludes his presentation to the Royal Society with these observations (as
printed in the Society’s Philosophical
Transactions):
“And in reasoning on this
subject, we must not forget to consider that most remarkable of circumstance,
that the source of the Heat generated by friction, in these experiments,
appeared evidently to be inexhaustible.
It is hardly necessary to
add, that anything which any insulated body, or system of bodies, can
continue to furnish without limitation, cannot possibly be a material
substance; and it appears to me to be extremely difficult, if not quite
impossible, to form any distinct idea of anything capable of being excited and
communicated in the manner the Heat was excited and communicated in these
experiments, except by MOTION.
I am very far from
pretending to know how, or by what means or mechanical contrivance, that
particular motion in bodies which has been supposed to constitute Heat is
excited, continued, and propagated; and I shall not presume to trouble the
Society with mere conjectures, particularly on a subject which, during so many
thousand years, the most enlightened philosophers have endeavoured, but in
vain, to comprehend.
But, although the
mechanism of Heat should, in fact, be one of those mysteries of nature which
are beyond the reach of human intelligence, this ought by no means to
discourage us or even lessen our ardour, in our attempts to investigate the
laws of its operations…
“Nobody, surely, in his
sober senses, has even pretended to understand the mechanism of gravitation;
and yet what sublime discoveries was our immortal Newton enabled to make,
merely by the investigation of the laws of its action!
The effects produced in
the world by the agency of Heat are probably just as extensive, and
quite as important, as those which are owing to the tendency of the particles
of matter towards each other; and there is no doubt but its operations are, in
all cases, determined by laws equally immutable.
Before I finish this
Essay, I would beg leave to observe, that although, in treating the subject I
have endeavoured to investigate, I have made no mention of the names of those
who have gone over the same ground before me, nor of the success of their labours,
this omission has not been owing to any want of respect for my predecessors,
but was merely to avoid prolixity, and to be more at liberty to pursue, without
interruption, the natural train of my own ideas.”
That experiment
of Count Rumford has, no doubt – as in his explicit acknowledgement – had a
long intergenerational and interpersonal gestation period, but his iconic
experiment here described surely was the eventual ‘birth’ of the laws of
thermodynamics, starting with his establishing the energetic equivalence of
‘Heat’ (in the parlance of the time) and Work, or in today’s parlance, the
identity of Energy, Work and Quantity-of-Heat.
As a result of
this re-acquaintance with the Four Laws – without which nothing in the Universe
that happens, happens – I updated one of my blogsite excursions based on Oliver
Morton’s book Eating the Sun. This sequitur can be found at
I count myself
lucky that Amazon, with its wide net also embracing second-hand bookshops, has
found Sanborn C Brown’s book for me. Not
only for being able to read Rumford’s own accounts of his work, but more
importantly for the Preface by the
editors of the ‘Commonwealth and
International Library of Science Technology Engineering and Liberal Studies’ under
whose auspices this book has seen the light of day in 1967. At the same time I
am sad because the only reason that this book has found its way into the second-hand
market is that a US university library released it from their collection.
Some excerpts
from this Preface may explain my
concern:
“The publication explosion
in scientific literature had dictated such an economy of publication space that
the periodical literature in physics at the present time is written in a
peculiar type of clipped language and laconic style which conveys nothing but
the bare outline of the scientific contribution…
“This has not always been
the case and in the eighteenth and early nineteenth centuries the accepted
scientific writings were often attempts at literary efforts which were aimed at
being as interesting to the general public as it was useful to the professional
natural philosopher…
“In this process of
streamlining and making efficient scientific reporting, something of real value
has been lost which shows up in many ways, including the currently popular
image of the scientific endeavour as one of inhuman attention to ‘cold fact’
and the reputation of the scientific enterprise as one in which the scientist
himself, as a human being, must never appear. The fact is, of course, that the
scientist today is just as human as the scientist of 150 to 200 years ago but
until we find some better way of transmitting scientific information than the
present written scientific communication to cope with the information explosion
of the modern scientific age, the current tendency will continue toward making
the scientific paper less and less readable to more and more people…
“Count Rumford typifies
much of the scientific enterprise of the eighteenth century. Few of the leading
research scientists were trained professionals…. It was an age in which the
learned society fulfilled the function of our present-day research laboratory
and the scientific communication was written to be interesting to the general
educated world…”
For the chance
of any user of that university library [Gonzaga University] to stumble upon this whole, more than
two printed pages long editorial Preface, would have warranted its retention.
Their loss is my gain, and I am thankfully drawing attention to it here.
