TABLE OF CONTENTS We define thermodynamics as the investigation of the dynamical and thermal properties of bodies, deduced entirely from the first and second laws of thermodynamics, without speculation as to the molecular constitution.
J. Clerk Maxwell
Classical thermodynamics is the only physical theory of universal content which I am convinced will never be overthrown.
Albert Einstein
Thermal physics can be defined as the study of all physical processes involving temperature or heat. However, the precise meaning of these two words needs to be examined carefully. We start with temperature.
We all have an intuitive sense of temperature ( Phew, it s hot in here ), but this sense is of very little use in physics because it is so subjective ( You think so? I find it rather chilly ). [1] To get a more objective view we use a thermometer, but what does it actually measure? What do we mean when we interpret the length of a column of mercury as a measure of temperature? Before we can answer these questions, we need to introduce the concepts of thermal equilibrium and of insulating (or isolating) and diathermal walls.
If we dip a mercury thermometer into coffee straight from the coffee machine, we see that the length of the mercury column changes initially, but soon settles down at a new steady value, the reading . The thermometer is now said to be in thermal equilibrium (which we will often shorten to equilibrium ) with the...
