The subject, though traditionally thought of as ​‘heat’, includes the study of processes which involve both energy and entropy (i.e. randomness). Applications go beyond physics into chemistry and biology and the energy and chemical industries. The course content attempts to maintain a judicious balance between a statistical approach to molecular systems and the traditional thermodynamic approach which provides a framework for relating the macroscopic properties of a system to one another. The topics covered here also provide the essential background for electives such as solid- state physics, soft condensed matter, astrophysics and biophysics offered further ahead in the physics programme. The emphasis in the pedagogy is to introduce abstract concepts like heat, work and entropy through specific examples and then more generally; reinforcing them further through laboratory based experiments and computational exercises.