Conceptual understanding of thermodynamics: A study of undergraduate and graduate students

Francis Patron, Purdue University

Abstract

There is a perception among college students that physical chemistry is an impossibly difficult subject. The hypothesis guiding this study is that this perception is caused by the mismatch between the physical chemistry curriculum and the cognitive needs of students, whose learning styles, misconceptions, and difficulties are not explicitly addressed. A qualitative approach was used to examine students' conceptions of concepts such as internal energy, enthalpy, heat capacity, entropy, and Gibbs free energy. Students' views about science, physical chemistry, and thermodynamics were also examined. The subjects of the study were nine undergraduate and graduate students taking introductory or review courses in thermodynamics. Data were obtained from twenty-five individual interviews, thirteen of which took place while respondents were taking a course and twelve after they had completed it. The interviews were tape-recorded and transcribed and the transcripts were analyzed by a cross-case comparison method. The results show that graduate students had many of the same difficulties and misconceptions as undergraduate students. After a semester, students retained a minimal understanding of the main ideas of thermodynamics and the connections between them. They had a limited understanding of the relevance of thermodynamics to chemistry. Students regarded mathematical derivations as a fundamental component of thermodynamics and relied exclusively on mathematical equations to represent concepts such as enthalpy. Mathematical presentations were emphasized in lectures. The mathematical and pictorial symbols that students copied from the blackboard did not necessarily hold the same meaning for them as they did for professors. Many students had difficulty connecting mathematical symbols to physical concepts. They often confused the macroscopic and microscopic pictures and did not understand the concept of equilibrium. They never mentioned equilibrium in their descriptions of the science of thermodynamics. Students did not make connections between thermodynamic concepts such as internal energy and their prior formal knowledge.

Degree

Ph.D.

Advisors

Bodner, Purdue University.

Subject Area

Science education|Higher education|Chemistry

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