Investigating the mangle of teaching oxidation-reduction with the VisChem approach: problematising symbolic traditions that undermine chemistry concept development

Specific to the topic of oxidation-reduction (redox), teachers are obligated by the discipline to prioritise symbolic traditions such as writing equations, documenting oxidation states, and describing changes (e.g., what undergoes oxidation/reduction). Although the chemistry education research community endorses connecting the vertices of Johnstone's triangle, how symbolic traditions undermine chemistry concept development, especially during lesson planning and teaching, is underexplored. To clarify this gap, we use the Mangle of Practice framework to unpack the clash between symbolic vs. particulate-focused instruction. We investigate teachers' (n = 3) co-planning and micro-teaching of a redox learning design at the VisChem Institute-2 using a narrative approach and video research methods. Our results show that the traditions of redox instruction are problematically entrenched in chemistry symbols. Mnemonics, the single replacement reaction scheme, and the written net ionic equation all constrain instruction focused on chemical mechanism and causality in various ways. We assert that the nature of redox knowledge in terms of what is worth teaching and learning must first be re-evaluated for reform-based efforts to succeed. Implications and suggestions for chemistry teaching and research at both secondary and tertiary levels are discussed.