From everyday chemistry to formal modeling: a progressive approach to integrating systems thinking in chemistry

Abstract Systems thinking in chemistry involves reasoning that integrates the macroscopic, microscopic, symbolic, and process-level representations of bounded systems. This article proposes a practice-oriented progression from a deliberately simplified everyday chemistry task to formal conceptual modeling for non-chemistry-major undergraduate engineering students. The coffee-machine lead-contamination task is author-constructed and is presented as a design exemplar; it was not administered to the students analyzed here. The empirical component draws on three illustrative student-generated Object-Process Methodology (OPM) models of olive mill wastewater treatment (OMWT), interpreted through a dual lens of chemical representational depth and Model of Systems Thinking (MOST). Across these illustrative models, OPM makes system boundaries, major components, and process sequences readily visible, whereas mechanistic, conditional, and monitoring-based reasoning remains only partially explicit. These findings suggest that systemic framing alone is insufficient for a molecular-level explanation and that deliberate scaffolding is needed to connect system-level behavior to chemical mechanisms. OPM serves as a diagnostic and pedagogical tool for integrating processes, components, and broader implications in chemistry contexts.