In an ideal instructional context, one would expect the components (teacher, content and instructional strategy) to operate in harmony, in tandem and in a complementary manner. When these components are not in harmony, they are said to be in a state of ‘instructional contextual contestation’. The components compete rather than complement each other. This article presents a multiple-case study of such contestations in the teaching of chemical equilibrium, a fundamental concept in chemical reactions that has been found to be difficult to teach. Four experienced teachers from three secondary schools with consistently impressive National School Certificate results were selected to participate as cases. Triangulated analysis and interpretation of data generated from biographical questionnaires, one-on-one interviews, classroom observations and document analysis were used to find teachers’ created instructional contexts, using both individual and cross-case analyses. Interpretation of the results indicates that there are contextual contestations within and across cases. In particular, two components, assessed curriculum content and the nature of the teacher, dominated the context created in all cases. Teachers’ strategy was showing and telling what learners needed for the examination: direct teaching, questioning, modelling and practising past questions. Only content that is normally assessed was taught: relevant terminology, application of Le Chatelier’s Principle, related industrial processes and table method for Kc calculation. Therefore, the nature of chemical equilibrium and relevant instructional strategy used to teach the topic of chemical equilibrium became insignificant.

中文翻译：

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化学平衡教学中的教学情境竞赛：多案例研究

在理想的教学环境中，人们希望组件（教师，内容和教学策略）能够协调，串联和互补地运作。当这些组成部分不一致时，它们被称为处于“教学上下文竞争”状态。各组成部分相互竞争而不是相互补充。本文介绍了在化学平衡教学中此类竞争的多案例研究，化学平衡是化学反应中的一个基本概念，已被发现很难教授。来自三所中学的四名经验丰富的老师获得了令人印象深刻的“国家学校证书”成绩，作为案例参加。对传记式问卷，一对一访谈，使用课堂观察和文件分析，通过个体和跨案例分析，找到教师创建的教学环境。结果的解释表明，案例内部和案例之间存在上下文竞争。特别是，在所有情况下，所评估的课程内容和教师的性质都是由两个部分构成的。教师的策略是展示并告诉学习者考试所需的内容：直接教学，提问，建模和练习过去的问题。仅讲授通常评估的内容：相关术语，Le Chatelier原理的应用，相关的工业过程以及用于Kc计算的表格方法。因此，