Enhancing understanding of physical and chemical change by macroscopic and particulate level visualizations

The purpose of this study was to investigate whether CHEM-PHYS 102 students' understanding of physical and chemical change was enhanced by experiencing an activity in which they interacted with visualizations of physical and chemical change at the macroscopic and particulate levels. Students were administered a pre test prior to instruction on physical and chemical change. Mid semester they participated in one of three visualization treatments, and at the end of the semester a post test was administered. The research questioned explored in this study were: 1) Does participation in the PCAct affect students' ability to correctly distinguish physical and chemical changes as measured by the pre and post PCA? 2) When students are specifically cued with particulate level visualizations is there an increase in the frequency of particulate level explanations? 3) Is the explanation perspective of the student consistent with the stimulus? And 4) How many particulate visualizations on the PCAct must students experience to increase the frequency of particulate level explanations on the post PCA?;This study specifically analyzes the visualization treatment, physical and chemical change activity (PCAct), and uses scores on students' performance on the post test to measure gains. Methods of analysis included independent and dependent samples t tests, a correlation matrix, and graphs. Significant findings from this study demonstrated that students continue to struggle with particulate explanations for chemical and physical change. Students showed an overwhelming propensity to discuss changes of mater at the macroscopic level. Multiple exposures to visual images at both the macroscopic and particulate level showed significant growth in students' ability to determine a chemical and physical change. Overall results indicated that while students' ability to distinguish between a chemical and physical change increases with visual images they continue to lack a deeper understanding of the particulate level and describe the concept.