enormously rich and logically consistent intellectual framework from within which to
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enormously rich and logically consistent intellectual framework from within which to
characterize macroscopic behavior composed of unknown molecular mechanisms.
Ideas about entropy grew out of William Thomson's (a.k.a Lord Kelvin)
thermodynamic laws about energy conservation and its allowable transformations.
Later Clausius decomposed the energy into that which was available for mechanical
work, called work-content, and that which was not, called transformation content.
He referred to the transformation content, a reflection of what changes in the
internal order properties of the system that occurred as a concomitant of changes in
energy and heat, as the entropy.
Rudolph Clausius added the word entropy as a thermodynamic property to
the conceptual armamentarium of theoretical physics in about 1865. This followed
the earlier work of the French engineer, Nicolas Leonard Sadi Carnot, who was
trying to develop a theoretical framework within which efficiencies in heat-
generating engines might be understood. It implicated positive, > 0, changes, d, in
entropy, S, with changes in time, ¢, .e. “ > 0, entropy is increasing in time, as a
concomitant of the inevitable mechanical inefficiencies in an energy driven system.
The resulting losses in the form of wasted energy show up as increases in
molecular motion, which could be estimated from the increases in heat. Wasted
energy dissipated as heat increases the amount of random motion and volume
occupied by the surrounding molecules in physical processes involving heat,
pressure, vaporization, condensation and work; all elements of that era’s dominant
physical metaphor, the steam engine.
The highly developed, multifaceted, often quite abstract formal
characteristics of the inferred property, entropy, prevent glib definitions and
generalizations. In the context of Kelvin-Clausius theory, the entropy of a closed
system will remain the same if it is isolated from any matter or energy exchanges
with the environment. If heating a system such that the change, d, in heat, Q, is
positive, i.e. dQ > 0, it experiences a rearrangement in its microstructural motions,
but the temperature is left unchanged. The (inferred) entropy, S, increases (i.e., dS
> Q) as the ratio of change in added heat, dQ, over the unchanging, absolute
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