DOI
https://doi.org/10.1021/acs.jchemed.9b00210

Summary
This paper presents the development of learning materials to help students understand systems thinking with respect to the Brønsted–Lowry acid–base model, which requires the concept of chemical equilibrium from a complex reactions perspective. According to the authors the Brønsted–Lowry acid–base model requires complex systems thinking because it considers random interactions between reactant and product particles and effective particle collisions in forward and reverse reactions. The system elements are dynamic, complex, and mutually independent. Furthermore, phenomena constantly change and interconnect with all elements of the system. Based on ontological analysis of Brønsted–Lowry acid–base model, this paper proposes a Scratch program to help students understand it.
The ontological analysis divides the science concepts into matter and process views. Furthermore, the process view is divided into sequential and emergent processes. Chemical equilibrium belongs to an emergent process category in the process view. The matter view is the idea that matter properties come from the material, whereas the process view is the idea that matter properties originate from the relation between the material and the surrounding environment. Sequential processes involve only a single direction for the interactions among elements. Understanding only one component of the interactions among the elements can, therefore, render the entire system understandable. However, the emergent process contains different directions for the various interactions among the elements, and these interactions occur simultaneously. Therefore, a partial understanding of the interactions among elements does not lead to an understanding of the entire system in the emergent process. We must consider collective summing or the net effect of all interactions. The Brønsted–Lowry acid–base model belongs to the emergent process category because it simultaneously considers the reactions between acids and bases in the forward reaction and the conjugated acid and base reactions in the reverse reaction, as well as the various materials that randomly interact with each other.
The teaching materials presented in this paper can be used for students to observe the emergent process visually to overcome their limitations with complex systems thinking. Furthermore, it is recommended that students self-code to understand more fundamental mechanisms.

Relevance for Complex Systems Knowledge
This paper deals with “systems thinking” and “complex systems”.
“systems thinking” Authors define systems as dynamic, complex, and mutually dependent, and recognize that phenomena always change constantly and are interconnected with all aspects of the system.
They consider systems thinking as the ability to look at the entire system and not the individual elements of that system and they describe three main characteristics of system thinking: (a) a feedback loop structure, which focuses on continuous formation of a relationship between elements rather than the characteristics of each element in the system; (b) a focus on comprehensive thinking (i.e., the system is not a simple sum of elements and all its properties are expressed through the relationships among the elements); (c) dominant feedback exists among various feedbacks. Various feedbacks exist in the system, but there are specific feedbacks that determine the overall characteristics of the system. These dominant feedbacks shift to different feedbacks depending on the conditions.
“complex systems” Authors defined all systems as dynamic, complex, and mutually dependent.

Point of Strength
The purpose of learning materials to help students understand systems thinking from a complex reactions perspective.