Kinyota, Mjege2022-03-122022-03-122020-03-09http://hdl.handle.net/20.500.11810/5846The importance of enabling student-teachers to acquire informed conceptions of the Nature of Science (NOS) is widely emphasised. Hence, this study investigated the effectiveness of a science pre-service teacher education programme of one university in Tanzania in enabling student-teachers to acquire informed conceptions of NOS as stages in a Learning Progressions model. We employed a comparative impact study design where NOS conceptions were compared resulting from two interventions—science student-teachers trained in inquiry-based learning (IBL) (N=154) and those trained in IBL plus a NOS course (N=86). The first teacher education programme emphasises learning through IBL, thus assuming that students will automatically acquire NOS conceptions through experiencing IBL. The additional NOS course targets explicit instruction of three NOS aspects, i.e. the tentative nature of scientific investigations, the scientific method and scientific theories and laws. Moreover, non-science student-teachers were used as a baseline control group (N=106). Findings indicated that generally student-teachers had limited conceptions of NOS, implying serious gaps in NOS learning progression. Neither experiencing IBL nor being trained in an additional NOS course had significant impact on student-teachers’ understanding of NOS. Largely, our findings imply that the preservice science teacher programmes are not sufficiently enabling student-teachers to acquire informed conceptions of NOS, a condition that calls for immediate intervention. We recommend a comprehensive review of the NOS progression. In the meantime, for the pre-service education programme we recommend a stand-alone and compulsory NOS course that explicitly addresses all of the aspects of NOS.enNature of Science, Tanzania; science educationhttps://doi.org/10.1080/18117295.2022.2041788