This article investigates how interactive representations can be used to enhance conceptual learning. It is a naturalistic study of 14 students in four groups aged 16--17 years working with an interactive simulator. The article is based on qualitative data to enable analyses of the students' processes of conceptual learning as interactive sense-making, as discussions, verbalisation and use. The activities of the learners are studied in detail from a socio-constructive perspective with regard to how they relate previous knowledge and experiences to theory, investigating the progress of conceptual learning inspired by the notion of a coordination class (diSessa, A. A., & Sherin, B. L. [1998]. What changes in conceptual change? "International Journal of Science Education," 20(10), 1155-1191. doi:10.1080/0950069980201002). This process brings design issues related to conceptual learning to the fore. The study points towards a revised inquiry approach in which a digital representation can be used to negotiate a meeting point between theory, previous experience and knowledge, and be instrumental in conceptual sense-making.