Developing scientific reasoning (SR) is a central goal of science-teacher education worldwide. On a fine-grained level, SR competency can be subdivided into at least six skills: formulating research questions, generating hypotheses, planning experiments, observing and measuring, preparing data for analysis, and drawing conclusions. In a study focusing on preservice chemistry teachers, an organic chemistry lab course was redesigned using problem-solving experiments and SR video lessons to foster SR skills. To evaluate the intervention, a self-assessment questionnaire was developed, and a performance-based instrument involving an experimental problem-solving task was adapted to the target group of undergraduates. The treatment was evaluated in a pre-post design with control group (cook-book experiments, no SR video lessons) and alternative treatment group (problem-solving experiments, unrelated video lessons). Interrater reliability was excellent (ρ from 0.915 to 1.000; ICC (A1)). Data analysis shows that the adapted instrument is suitable for university students. First insights from the pilot study indicate that the cook-book lab (control group) only fosters students’ skill in observing and measuring, while both treatment groups show an increase in generating hypotheses and planning experiments. No pretest-posttest differences were found in self-assessed SR skills in the treatment groups. Instruments and data are presented and discussed.

Understanding and knowledge of scientific reasoning skills is a key ability of pre-service teachers. In a written survey (open response format), biology and chemistry pre-service teachers (n = 51) from two German universities claimed central decisions or actions school students have to perform in scientific reasoning in the open inquiry instruction of an experiment. The participants’ answers were assessed in a quality content analysis using a rubric system generated from a theoretical background. Instruments in a closed response format were used to measure attitudes towards the importance of diagnostics in teacher training and the domain-specific expectations of self-efficacy. The pre-service teacher lacked pedagogical (didactics) content knowledge about potential student difficulties and also exhibited a low level of content methodological (procedural) knowledge. There was no correlation between the knowledge of student difficulties and the approach to experimenting with expectations of self-efficacy for diagnosing student abilities regarding scientific reasoning. Self-efficacy expectations concerning their own abilities to successfully cope with general and experimental diagnostic activities were significantly lower than the attitude towards the importance of diagnostics in teacher training. The results are discussed with regard to practical implications as they imply that scientific reasoning should be promoted in university courses, emphasising the importance of understanding the science-specific procedures (knowing how) and epistemic constructs in scientific reasoning (knowing why).