During the last decades, digital technologies have become more common in providing opportunities for reflection and in-depth analysis of classroom practices and have afforded new ways of organizing teacher education. In particular, videotaped lessons have proven to be a valuable tool for capturing teaching episodes, subsequent reflection and development of student teachers’ professional knowledge, here referred to as ‘pedagogical content knowledge’ (PCK). The aim of this project was to investigate how the use of the reflective tool, content representations (CoRes) in combination with video and associated digital tools might be used as a means for capturing student teachers’ professional knowledge of practice. In the study we explore how a group of 24 secondary science student teachers were provided with Content Representations (CoRe) and video annotations to support their reflection-on-actionduring their practicum. Video annotations, alongside a written reflection of critical incidents in the student teachers’ teaching constituted data for analysis. Our findings suggest that the different tools enabled the student teachers to connect captured examples of teaching instances with theoretical issues, and in this way offered the ability to see as well as to analyse their teaching practice. As such, the CoRe, together with the video annotation tool, proved to be successful in scaffolding and structuring student teachers’ reflection-on-action, allowing them to connect their reflections to components of PCK and further to articulate connections between these components. © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.