HOW TO USE THERMODYNAMICS TO DEAL WITH SOME THERMAL SYSTEMS OUT OF EQUILIBRIUM

Abstract

It is shown at a level suitable for an undergraduate student that thermodynamics can be use to deal with certain thermal
systems out of equilibrium. The trick is to cut the system in parts or slides small enough so that the thermodynamics
magnitudes have constant values inside them. As an example, an ideal gas in a thermal gradient is considered. It is shown
that a density gradient appears as a consequence of the thermal one. It is also briefly considered the heat conduction in
a rod; it is shown that the entropy production rate can be calculated both for the reservoirs and the rod.