The Response of Uniform Bodies to Heating

Abstract

This chapter will present theories of the thermodynamics of some simple materials. While we already possess the generic laws necessary for dynamics (Chapter 1), we cannot really claim to know how certain types of bodies will behave when subjected to heating. Only specific constitutive laws allow for the actual creation of theories of dynamics. The following sections are largely devoted to the thermodynamics of the ideal gas, a simple model fluid which can undergo changes of temperature and of volume. We will be able to compute adiabatic, polytropic, and more general processes undergone by this gas. The simple model chosen allows only for reversible processes, which means that we can actually set up a thermodynamics of nondissipative processes. The ideas will be applied to a couple of other ideal and simple systems, namely magnetized bodies, and blackbody radiation. Finally we shall contrast the results with a brief look at the thermostatics of simple systems.

...the old ‘impressive, clear, and wrong’ statements regarding latent heat, evolution and absorption of heat by compression, specific heats of bodies and quantities of heat possessed by them, are summarily discarded. But they have not yet been generally enough followed by equally clear and concise statements of what we now know to be the truth.

W. Thomson (Lord Kelvin), 1878