4 Classical thermodynamics

In this chapter, we are going to forget about statistical physics, and return to

the early 19th century, when we didn’t know that things are made up of atoms.

Instead, people just studied macroscopic objects and looked at macroscopic

properties only.

Why are we doing this? Now that we have statistical physics, we can start

from microscopic properties and then build up to the macroscopic properties.

The problem is that we can’t always do so. So far, we have been working with

rather simple systems, and managed to derive their macroscopic properties from

the microscopic ones. However, in real life, a lot of systems have very complex