Thermodynamics is the study of energy change.
concerned with the equilibrium states of a system, and not by the path with which
the system arrives at these states.
Yet, once a specific material is selected for the
system, how that materials state variables (pressure, volume, temperature, etc.)
relate to its equilibrium states, and the work done to move between these states,
are also of interest.
State variable relationships and work-energy relationships, in
some cases, depend on specific processes undergone by the system (path
functions), and in other cases depend only on the initial and final states of the
system (point functions, or state functions), not on how the system arrives at its
The seeds of thermodynamics, in this authors’ opinion, were planted by the
engineers first concerned with the dream of a heat engine.
The dream was to
create a device, which would in one cycle, consume a quantity of heat and
produce an equal quantity of work.
Today, although we understand that it is
impossible to produce an EQUAL amount of work, the study of this “heat to work”
energy conversion creates the basis of the science of classical thermodynamics.
It is possible to derive the concepts of thermodynamics entirely by sound
mathematical reasoning, and many authors do so.
Here, we will attempt to
include physical models, both MACRO and MICRO, to impart a deeper
understanding of the topic.
We start with a brief discussion of temperature
One can hardly hear the word thermodynamics with out
seeing a thermometer in one's mind.
Truly, this device is fundamental in the
experimental world of heat.
But rarely do we consider what the device is actually
Here, we will explore that question.
The name of Gabriel Fahrenheit (1686-1736) is associated with temperature
in the minds of most people.
Fahrenheit, a medical doctor, explored the
correlation between a patients’ state of health and the value of the temperature.