Why learning redox is difficult even with animations – students’ adherence to cognitive resources

Students face many challenges when they learn redox reactions at the submicroscopic level. Animations have been shown to support students’ learning, but some students may not interpret the animations as intended. Guided by the cognitive resources, or the Knowledge in Pieces perspective, this study examined how students made sense of redox reactions after they engaged in different animation activities. Our participants were 15 first-year university students taking introductory chemistry courses. Besides their written responses to diagram-based post-animation questions, we also interviewed six of these 15 participants so that they could elaborate on their written responses. We identified two cognitive resources to which students strongly adhered when reasoning about redox reactions. The first, ion pair , reflects the idea that ions remain bonded as pairs in solution. The second, ion attraction , frames redox reactions as interactions between oppositely charged ions. While these ideas have been reported elsewhere, we argue that they are key to students’ sense-making of redox because, in determining the best representation of redox reaction, students primarily focused on whether ions appeared paired or whether opposite charges could “react”. Furthermore, we suggest that these two cognitive resources could explain students’ alternative conceptions in other chemistry topics such as bonding, structure and properties, solution chemistry, and elements/compounds. Our findings suggest that instruction and animation design could help students visualise ion distribution before electron transfer, and support students to see the values and limitations of ion pair and ion attraction in different contexts.