Inspired by Shulman’s question ‘where do teachers’ explanations come from?’, this study explores two issues: the extent to which student teachers (STs) of physics can detect consequential gaps in a given explanation (RQ1), and the extent to which they will sacrifice simplicity for completeness when designing an explanation for a given audience (RQ2). The chosen topic was the rainbow; focussing on the case of the primary rainbow, a very limited explanation based on the interaction of a raindrop with a ray of sunlight was discussed with 33 STs, using two successive questionnaires. The results suggest that the STs were often largely unaware that the explanation was deeply incomplete (RQ1). This was accompanied by the lack of a ‘functional approach’ questioning how a changed variable might affect the phenomenon in question, even where this involves accepting a patently incoherent explanation. In relation to RQ2, the results suggest that the simplicity-coherence issue often remained unresolved for STs even after a critique of the explanation’s incompleteness. The final part of the paper centres on teacher preparation and the need to more explicitly address the simplicity-coherence dilemma in order to help STs to develop their critical awareness and responsible choice of explanations.

受舒尔曼的问题“教师的解释从何而来？”的启发，本研究探讨了两个问题：物理学的学生教师 ( ST ) 可以在多大程度上发现给定解释 (RQ1) 中的间接差距，以及在为特定受众设计解释时，他们会为了完整性而牺牲简单性（RQ2）。选择的主题是彩虹；关注主彩虹的情况，使用两个连续的问卷，与 33 个ST讨论了基于雨滴与阳光相互作用的非常有限的解释。结果表明，STs 通常在很大程度上不知道解释是非常不完整的（RQ1）。伴随而来的是缺乏“功能方法”来质疑改变的变量如何影响所讨论的现象，即使这涉及接受明显不连贯的解释。关于 RQ2，结果表明，即使在对解释的不完整性提出批评之后，ST s的简单性-连贯性问题通常仍未解决。论文的最后一部分集中在教师准备和更明确地解决简单-连贯困境的需要上，以帮助ST培养他们的批判意识和负责任的解释选择。