ABSTRACT
Researchers believe that the way that students talk, specifically the language that they use, can offer a
window into their reasoning processes. Yet the connection between what students are saying and
what they are actually thinking can be ambiguous. We present the results of an exploratory
interview study with 10 participants, designed to investigate the role of language in university
physics students’ reasoning about heat in thermodynamic processes. The study revealed two key
findings: (1) students’ approaches to solving certain heat-related problems are related to the way
in which they explicitly define the word ‘heat’ and (2) students’ tendency to reason with heat as a
state function in inappropriate contexts appears to be connected to a model of heat implicitly
encoded in language. This model represents heat or heat energy/thermal energy as a substance
that moves from one location to another. In this model, students talk about thermodynamic
systems as ‘containers’ of heat, and temperature is a measure of the amount of heat ‘in’ an object.
In this paper we will explore the interplay between how university physics students
speak and how they reason about heat in thermodynamics processes. We will focus
on one particular area of student reasoning in thermodynamics: several studies in
physics and chemistry education have found that there is a recurring pattern in
student reasoning about thermodynamics processes. Specifically, a majority of univer-
sity-level physics and chemistry students conceptualize heat as having the character-
istics of a state function (an extensive thermodynamic quantity that is independent of
thermodynamic path) (Fuchs, 1987; Kaper & Goedhart, 2002; Loverude, Kautz, &
Heron, 2002; Meltzer, 2004; Roon, Sprang, & Verdonk, 1994). For example, in an
interview study of 32 students enrolled in a calculus-based introductory university
physics course, Meltzer (2004) found that 69% of the interviewees said that the
total heat transfer for a closed thermodynamic cycle was zero. He observed that stu-
dents most commonly argued (incorrectly) that the heat transferred into and out of
the system during the cycle would be the same because the initial and final tempera-
tures of the system were the same. Students focused on the beginning and end points
of the process and ignored the path that was taken. This is the essence of state
function-like reasoning.
