  To date, there is a lack of research on learning environments for pre-service
physics teachers that allow them to learn and practise diagnosing students'
conceptions that are (currently) not covered in physics education textbooks
(e.g. students' conceptions about viscosity). In this study, we developed and
piloted such a learning environment, which was implemented and piloted twice in
a seminar for pre-service physics teachers. As coping with a diagnostic process
is particularly demanding for pre-service physics teachers, our accompanying
research aims to identify learning barriers within our developed learning
environment. The results indicate that the participants experience the learning
environment with varying degrees of difficulty. One main difficulty for
pre-service physics teachers seems to be in interconnecting their content
knowledge with their pedagogical content knowledge in the diagnostic process.
