Pedagogical content knowledge is considered a valuable knowledge base for all science teachers. Thus, promoting its development in all pre-service teacher programmes including a short 1 year Physical Science postgraduate certificate in education (PGCE) course is desirable. This paper focuses on the comparison of topic-specific pedagogical content knowledge (TSPCK) at a level of planning to teach between PGCE pre-service teachers (n = 8) and final (fourth) year traditional BEd pre-service teachers (n = 16). Both groups were exposed to an intervention targeting the development of TSPCK in Physical Science topics taught in South Africa’s national secondary school curriculum. Data collected from both groups comprised pre–post intervention TSPCK tests and content representations tool for chemical equilibrium. The data analysis entailed the use of a criterion-based rubric for shifts in the quality of planned TSPCK and the content representations were analysed through an in-depth qualitative analysis. The findings revealed an improvement in the PGCE pre-service teachers’ planned TSPCK to the same extent as for the BEd pre-service teachers. The PGCE pre-service teachers did not indicate being at an initial advantage in their TSPCK because of their strong content knowledge, but they showed a faster growth path in developing TSPCK. Recommendations made include the promotion of TSPCK discussion in the PGCE programme and a possible re-positioning of such discussions in the BEd programme.

教学内容知识被认为是所有科学教师的宝贵知识基础。因此，在所有职前教师计划中促进其发展，包括短期的 1 年物理科学教育研究生证书 (PGCE) 课程是可取的。本文侧重于PGCE职前教师（n  = 8）和最后（四年）传统BEd职前教师（n = 16）。两组都接受了针对在南非国家中学课程中教授的物理科学主题中发展 TSPCK 的干预。从两组收集的数据包括干预前后的 TSPCK 测试和化学平衡的内容表示工具。数据分析需要使用基于标准的量规来改变计划的 TSPCK 质量，并通过深入的定性分析对内容表示进行分析。调查结果显示，PGCE 职前教师计划的 TSPCK 改善程度与 BEd 职前教师相同。PGCE职前教师并没有因为他们丰富的内容知识而在他们的TSPCK中表现出最初的优势，但他们在发展TSPCK方面表现出更快的增长路径。