PHYS 304: Thermodynamics and Statistical Physics

Instructor: Alex Travesset (web page)

"A theory is the more impressive the greater the simplicity of its premises, the more different kinds of things it relates, and the more extended its area of applicability. Therefore the deep impression that classical thermodynamics made upon me. It is the only physical theory of universal content which I am convinced will never be overthrown, within the framework of applicability of its basic concepts." Albert Einstein.

Lecture 10 notes (Adiabatic vs Isothermal processes in gases)

Unless a gas is compressed super-fast (what super-fast means was discussed in lecture 6), the process is approximately quasistatic.

If the gas is compressed fast, there is no time for the system gas to reach equilibrium with the container, and, as a result, almost no heat is exchanged and the process is adiabatic . After the compression, the temperature of the gas will be much higher than the container, and heat will be exchanged by conduction, untill the temperature of the gas becomes the same as the environment. Homework 4 consisted in calculating the temperature of a piston for stopping trains at the end of a rail line. Spencer (Dewald) took pictures of the pistons in Antwerp, Belgium. See below.

An isothermal expansion of the gas would require a slow compression of the gas, such that, at any time, equilibrium between gas and container is always established.

Lecture 9 notes (Stirling Engine)

Wikipedia has an excellent page on the Stirling engine (link)

A movie showing how the engine works can be found at Youtube (link)

Lecture 4 notes (Definition of Temperature)

The ideal gas law scale is one of the many possible scales that provides a rigorous definition of temperature. The top figure shows the determination of the vaporization temperature of water at p=1 atm, while the bottom one the determination of a superconductor temperature using this scale. The temperatures obtained are T=373.125 and T=160.00.

How to succeed in PHYS304

Thermodynamics is mathematically simple but conceptually challenging. It is for this reason that you may get lost when studying the subject. I have had many students in the middle (or later!) of the semester asking me the question How should I study for this course? I hope this will not happen to any of you, so here is my answer:

First, do not miss any class. It is going to be really difficult, and likely you will get lost, if you try to study this subject on your own (and I will not be following the book all the time). Try hard to make sense of what I teach in class, ask questions, both in class and in private.

Second, besides the homework, study the subject on a regular basis , not by memorizing the book or class notes, but rather by asking yourself do I understand this? Am I able to solve problems without looking at the solutions?

Third, do your homework yourself . It is much better to get a moderate grade after you worked hard on the problems than getting a perfect score by copying from a classmate: it will show in the exam, which counts a lot more towards the final grade. Be willing to spend time trying to solve the problems and do not wait till the night before the due date.

Fourth, do supplementary problems and make sure you get till the end with actual numbers. I have provided a long list of extra problems. They are in reserve in the Library. I know that it is somewhat annoying to have to go to the Library, but unfortunately, that is the only possible option.

If you follow this four rules, I guarantee that you will learn PHYS304 and get a really top grade.