This chapter considers multimodal data collected in a university-level Science Education subject. Mediation-in-interaction, inspired by sociocultural learning theory and ethnomethodological/ conversation analysis (CA) is the guiding conceptual tool. The analysis is mainly concerned with how student participants of a particular sequence of classroom interaction: (1) define the ‘problems’ to be solved; and (2) define and make use of different resources (artefacts, concepts, etc.) in the mediational process; thereby shaping and regulating the context and course of their learning. The analysis demonstrates how different students focalise different leaning objects in completing the task. It is further observed throughout the sequence how students regulate their own and each other’s talk in English; drawing on multimodal and plurilingual resources, among others, available to them. As the students shift their attention to scientific problems, their mobilisation of resources from languages besides English increases. Furthermore, attention to scientific content can be seen to create the sequential context for focusing on language and vice versa.