IDENTIFYING AND ADDRESSING SPECIFIC STUDENT DIFFICULTIES IN ADVANCED THERMAL PHYSICS

Physics education research (PER) is the study of how people think about, learn,
understand, and teach topics in and related to physics. One goal of PER is to identify
student difficulties with a particular topic and to develop curricular materials to
address these difficulties. Results in PER show that guided-inquiry worksheet activities
(a.k.a. tutorials) can be effective supplements to traditional lecture instruction
in introductory physics classes. Recent research suggests that tutorials can also be
useful within upper-division courses.
I developed two tutorials for use within advanced undergraduate thermal physics
courses. One tutorial improves students’ understanding of the relationship between
heat engines (especially the Carnot cycle), entropy, and the Second Law of Thermodynamics.
Heat engines are an integral part of many thermodynamics courses,
as they provide a practical scenario in which all three laws of thermodynamics must
be considered. Carnot’s theorem is, in essence, a statement of the Second Law in
the context of heat engines, but my results indicate that students do not make this
connection. My tutorial helps students by guiding them through a derivation of
Carnot’s theorem starting from a standard statement of the Second Law.
My second tutorial helps students gain an appreciation for the physical and
mathematical origin of the Boltzmann factor and when it is applicable. The Boltzmann
factor is a mathematical expression for the probability that a thermodynamic
system has a certain energy. The Boltzmann factor may be used to determine
many properties of the system and is, therefore, a cornerstone of statistical thermal
physics. My results indicate that students often do not recognize situations in which
the Boltzmann factor is appropriate, nor do they understand where this particular
mathematical expression comes from.
Results from implementing my tutorials within the advanced thermal physics
courses at the University of Maine indicate that students gain a better understanding
of relevant topics after tutorial instruction, compared to lectures alone. Results from
other schools indicate that difficulties observed before tutorial instruction in our
classes are not unique, and that the Boltzmann factor tutorial can be an effective
replacement for lecture instruction.