Alternative Concepts Held by Community College Chemistry Students about Physical Properties and Processes: Density, Solubility, and Phase Changes

Abstract

The purpose of this study was to determine what alternative conceptions about density, solubility, and phase changes are held by community college chemistry students and to determine if traditional lab activities aid in promoting conceptual understanding of these three topics. The setting for the study was a large community college in North Carolina. The subjects were 38 students enrolled in a college-level general chemistry course.

Students in the study were given a pre-test consisting of 10 multiple-choice questions and 10 definitions they were to provide. They then completed three lab activities, one per week for three weeks, and were post-tested in the sixth week. The post-test was identical to the pre-test except for the order of the questions. The multiple-choice items on the pre- and post-tests were compared using t-tests. Comparisons were done for each item, for each subjects area, and for the test overall. The pre- and post-test definitions provided by the students were compared and analyzed for trends. Finally, based on the responses to the multiple-choice items and the definitions, six students were selected to be interviewed for each subject area.

The community college students were found to hold similar alternative conceptions about density, solubility, and phase changes as those cited in literature for high school and college students. Links of alternative conceptions to the particulate nature of matter and use of language were noted. The traditional lab activities did not enhance the students? conceptual understanding of the three subject areas.