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This study examined how 21 college-level general chemistry students, who had received instruction that emphasized the symbolic level of ionic equations, explained their submicroscopic-level understanding of precipitation reactions. Students’ explanations expressed through drawings and semistructured interviews revealed the nature of the misconceptions that they held. These misconceptions and recommendations for instructional changes to target the misconceptions are examined in this article.

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Molecular visualizations have been widely endorsed by many chemical educators as an efficient way to convey the dynamic and atomic-level details of chemistry events. Research indicates that students who use molecular visualizations are able to incorporate most of the intended features of the animations into their explanations. However, studies also suggest that learning from visualizations is imperfect. In this study a new theoretical framework, variation theory, was used to examine learning and understanding based on students' reported experience of variation while viewing visualizations. Student metacognition was examined to gain insight into how students recognized variation between their mental models and the visualization models. Results from this study provide visual evidence of a transitional state of understanding in which students' previous conceptions merge with new conceptions learned from the visualizations. However, limitations in students' ability to monitor their understanding made unpacking what students understood challenging, as students tend to communicate only what they believe to be the most essential details.

In this qualitative study, we examined how a group of seventeen first semester General Chemistry students responded when they were shown contrasting molecular animations of a reduction–oxidation (redox) reaction between solid copper and aqueous silver nitrate for which they first viewed a video of the actual experiment. The animations contrasted in that they portrayed different reaction mechanisms for the redox reaction. One animation was scientifically accurate and reflected an electron exchange mechanism, while the other was purposefully inaccurate and represented a physical exchange between the ions. Students were instructed to critique each animation for its fit with the experimental evidence and to ultimately choose the animation that they felt best depicted the molecular level of the chemical reaction. Analyses showed that most students identified that the electron exchange animation was the more scientifically accurate animation; however, approximately half of the students revised their drawings to fit with the inaccurate physical exchange animation. In addition, nearly all students thought that both animations were correct and useful for understanding salient information about the redox reaction. The results indicate that when students are shown contrasting animations of varying accuracy they make errors in deciding how the animations are supported and refuted by the evidence, but the treatment is effective. Contrasting animations promote students to think deeply about how animations fit with experimental evidence and is a promising way to engage students to think deeply about animations.