PHYS2210 Thermal Physics

See also Lecture Notes, Assignments, tutorials and past exams.

  • Level 2 Physics Course
  • UOC 3, HPW 2
  • Offered every year, Session 2

Lecturer: Professor Paul Curmi
Lecture Times: Monday 9-10 (Physics Lecture Theatre, OMB), Thursday 2-3   (Rm 112, Old Main Building)
Consultation times: Monday 10-11,  Thursday 3-4 (Rm 130, Old Main Building)

Brief Syllabus: Laws of thermodynamics, kinetic theory, microscopic processes, entropy, solid-state defects, Helmholtz and Gibbs' functions, Maxwell's relations, phase diagrams, chemical and electrochemical potentials.

Prerequisites: PHYS1002 or PHYS1022 or PHYS1111 or PHYS1221 or PHYS1231 or PHYS1241, MATH1021 or MATH1131 or MATH1141 or MATH1031; Excluded: PHYS2011.

Course Goals: Thermodynamics deals with energy, heat and work, and is essential to understanding the principles behind engines, refrigerators, and even life itself. This course aims to provide students with an introduction to thermodynamics. The course begins by considering kinetic theory and exploring how the various thermodynamic quantities, such as pressure, internal energy and temperature, and behaviours such as diffusion emerge from a simple consideration of a gas obeying basic classical physics. We then consider work and heat, looking at topics such as adiabatic processes, phase transitions, Joule-Thompson expansion and heat transfer. Based on these concepts, we will discuss the 1st law of thermodynamics, heat engines and their efficiency, and then Carnot’s work to derive the maximum possibly efficiency of heat engines. We will then look at how this leads to the concept of entropy and the 2nd law of thermodynamics, arguably one of the most debated laws of physics. To conclude, we will look at some of the ramifications of the 2nd law including concepts such as reversibility and the arrow of time, Maxwell’s demon and finally, Boltzmann’s entropy, which then leads directly into the PHYS3020 Statistical Physics course.

Learning Objectives
Students should develop the ability to:

  • Explain the key concepts of thermal physics and their consequences, in particular kinetic theory and the 1st and 2nd laws of thermodynamics.
  • Apply the key concepts of thermal physics to a variety of thermodynamic systems such as engines, refrigerators and the atmosphere.

Why Thermal Physics is important?
A knowledge of thermal physics –the physics of energy, heat, work and entropy – is essential to understanding the operating principles of a variety of useful technologies ranging from car engines and power stations to fridges and cooling elements. The concepts of entropy and reversibility are important to understanding chemical processes, in particular, which ones occur spontaneously and which ones don’t, how fast reactions proceed, and whether they consume or produce energy. Thermal physics is also important to the working of many biological systems such as molecular motors and cells, and even spreads as far as information technology, where the entropy of information is a key concept.
Thermal physics is also central to our understanding of physics itself. Quantum mechanics evolved from the failure of classical physics to explain the specific heat of gases and the spectra of a hot object (blackbody radiation). The 2nd law of thermodynamics is of great significance to understanding why most processes only go one way (e.g., why humpty dumpty can spontaneously fall off a wall and break, but doesn’t spontaneously reassemble and appear back on the wall), thereby providing us with the so-called ‘arrow of time’.

This course provides an important foundation for PHYS3020 Statistical Physics and PHYS3410 Biophysics 2.

How to Succeed – Strategies for Learning
Thermal physics can be a difficult subject because it has developed from studies in a wide range of fields including physics, chemistry, biology and many branches of engineering, mechanical and chemical in particular. These various influences have lead to a large number of slightly differing variables, definitions, and viewpoints that have evolved to ‘tune’ thermodynamics to specific applications. The key to this subject is to look for the central physical concepts, and how to apply them, rather than focus on the specific mathematical details, which tend to differ from one author’s field/viewpoint to another. This is particularly important to remember as you read amongst the various resources for the course.

Some further tips for successful learning include:

  1. Do not hesitate to ask questions during lectures. There is no such thing as a silly or wrong question. While your questions are helpful for you, they are also helpful for other students (you’ll often find other students in your class who have the same question but are too shy to ask), and they are helpful for the lecturer because they allow him/her to gauge whether they are getting the material across effectively or not.
  2. Considerable time should be spent ‘thinking’ about the subject, this may seem kind of obvious, but it goes much deeper than simply reviewing notes, reading resources or trying to memorize the various equations. You should try to spend some time after each lecture actively thinking about what you have learned. An ideal way to do this is to ask yourself questions such as “How does this fit into my existing knowledge of physics and my experience of how the world works?”, “Does this make sense?”, “How would I explain this to someone else?”, “Can I find some logical inconsistency or conflict that emerges from how I currently understand what I’ve learned?” (in which case you should aim to figure out and resolve this conflict), “What parts of what I’ve learned do I not fully understand?”, etc. In doing this, you may want to review your notes or books, but you should not see this as normal note-review or study (i.e. you shouldn’t do this by sitting there staring at your notes), to give an analogy, it should be more like being a Zen monk contemplating the sound of one hand clapping.
  3. Students should also try to do as many problems as possible – just doing the assignments is usually not enough. A variety of suggested tutorial problems will be given during the course, and some will be discussed during lectures. However, as individual students, you can help yourself by seeking out problems that make you confront aspects of the course that you least understand, just doing the easy questions will not help you very much. Forming small study groups to discuss the course material and work together on tutorial problems is highly encouraged, this approach will help you learn better by teaching each other (n.b. care should be taken that this doesn’t cross over to plagiarism for assignments – make sure you know the rules). Plagiarism guidelines.
  4. You should work throughout the course on compiling your own concise set of revision notes. A good way to do this is to write a brief review after each lecture. You should also add lessons learned in doing tutorial questions and from thinking about the lectures to these revision notes.

Finally, remember, don’t focus on just memorising all the equations (a formula sheet will be attached to the exam paper) – concentrate on the understanding physics instead, and the mathematical aspects should then follow naturally.


  • Two assignments worth 10% each (20% total)
  • 1 hour midsession exam 20%
  • 2 hour written final examination 60%


Recommended Reading

  • S.J. Blundell and K.M. Blundell, "Concepts in thermal physics" (Oxford)
  • D.V. Schroeder, “An Introduction to Thermal Physics” (Addison-Wesley) – A good, well-explained book on some key topics in thermodynamics and statistical mechanics.
  • Sears and Salinger, “Thermodynamics, Kinetic Theory and Statistical Thermodynamics” – Considered a standard text by many, but it is probably the most technical of the books listed here and can sometimes be difficult to follow. A good reference and worthwhile reading for more mathematically inclined students.
    (n.b., Please consider these books to be somewhat optional. This course will follow none of the listed books very closely, and none of the books will cover everything in the course in a single volume).

Additional References
It is always a good idea to consult more than one book when studying a course as you may find a book whose particular style is more suited to yours than the prescribed textbook. You will also benefit from studying different approaches to the course material and related problems; here is a short list of books that may be useful:

Adkins, “An Introduction to Thermal Physics” (Cambridge Univ. Press) – A short but thorough text on thermodynamics with many good problems.

Van Ness, “Understanding Thermodynamics” (McGraw Hill) – A short, old but very well explained book that contains some excellent insight into some of the more difficult concepts of thermodynamics.

Feynman, Leighton and Sands, “The Feynman Lectures on Physics” Vol. 1 (Addison Wesley) – This is an excellent text that contains many insightful explanations of a wide range of undergraduate physics topics, not just thermodynamics.

Zemansky and Dittman, “Heat and Thermodynamics” (McGraw-Hill) – A far more technical thermodynamics text but very comprehensive.

Sonntag, Borgnakke and Van Wylen, “Fundamentals of Thermodynamics” 6th Ed (Wiley) – A very good general textbook with a bit more mathematics than the Feynman lectures or Van Ness, and a lot of very good problems and worked examples.

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Further Information

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last updated 29 July 2013