DIFFICULTIES IN LEARNING THERMODYNAMICS, THAT HAVE THEIR ORIGIN IN THE SUBJECT MATTER

Thermodynamics is hard, according to a widely extended opinion of students that major in engineering, chemistry or science, and of many instructors, around the world. The difficulties in learning the subject have different sources pertaining to the contents, the textbooks, the students, the instructors, the academic institutions, etc. This paper particularly addresses those difficulties in learning the subject that can be traced back to the features of the content matter itself. The study is part of a program of research that investigates in an integral manner the main factors of the problem. A review of pertinent literature, a critical analysis of programs of study with their learning objectives, and many technical debates by a group of experts in physics teaching, pedagogy and psychology, led to the identification of the following set of difficulties directly linked to the content matter of thermodynamics:
a) Some of the principles of this subject can be stated in various ways, whose equivalence is not always easy to see. Yet, the student is expected to get a thorough understanding of them all, from the beginning, and use them in problem solving.
b) The classical approach to the subject is macroscopic. Looking into the microscopic structure of matter, in the hope of getting a better understanding of the concepts, is a debatable strategy. It can even prove misleading in some cases, if it is not properly used.
c) As thermodynamics is traditionally taught through its applications to particular physical systems, the student simply cannot learn the subject if he/she does not acquire, at the same time, a working knowledge of the physics of those systems (e.g. fluid mechanics in many cases).
d) Problem solving in this subject frequently needs the use of experimental information, e.g. some physical properties of substances. The retrieval of that information from tables and charts usually requires from the user special skills that the student needs to acquire along the way, to be able to deal with the problems.
e) The kind of problems that the student must be able to solve require maturity of judgement. The student will have to make simplifying assumptions and other considerations and decisions, to get to solve the problem with the information provided.
f) It is quite common in undergraduate engineering programs that the first formal course on thermodynamics is not a true introductory course to this subject.

Instead, it is a first course on thermal engineering. This poses a challenge for the student, who will get confronted with topics and problems from real-life engineering while still striving to understand the concepts and principles of thermodynamics itself. The paper includes some preliminary suggestions aimed to help the students and the instructors to contend with the kind of difficulties here described.