Investigation
of students’ reasoning regarding heat, work,
and
the first law of thermodynamics in an introductory
calculus-based
general physics course
Department of Physics and Astronomy, Iowa State
University, Ames, Iowa 50011
Many studies have
shown that pre-university students have substantial learning difficulties
related to heat,
temperature, and related concepts. However, very few investigations have
been reported that
focus on student learning of thermal physics concepts at the university
level. Here we report
on an investigation of reasoning regarding heat, work, and the first law
of thermodynamics
among students in an introductory calculus-based general physics
course. Responses to
written questions by 653 students in three separate courses were very
consistent with
results of detailed individual interviews carried out with 32 students in a
fourth course.
Although most students seemed to acquire a reasonable grasp of the
statefunction
concept, it was found
that there was a widespread and persistent tendency to
improperly
over-generalize this concept to apply to both work and heat. A large majority
thought that net work
done and/or net heat absorbed by a system during a cyclic process
must be zero, while
only 20% or fewer were able to make effective use of the first law of
thermodynamics even
after instruction was completed. Students’ difficulties seemed to stem
in part from the fact
that heat, work, and internal energy all share the same units. Results
were consistent with
those of previously published studies of students in U.S. and European
universities, but
portray a pervasiveness of confusion regarding process-dependent quantities
that was previously
unreported. The implication is that significant enhancements of current
standard instruction
may be required for students to master basic thermodynamic concepts.