The aim of this article is to investigate how new materialist philosophies of matter can help us study the emergence of scientific thought in young children's activities. We draw extensively on the work of Gilles Deleuze to help us understand scientific concepts as concrete universals. In particular, we show how the concept of force is re-animated through this approach, becoming less deterministic, and more inflected with chance and indeterminism. We show how this approach to concepts moves beyond constructivist socio-cultural theories of learning, and reveals how concepts are "material articulations of the world" intra-acting with all other matter and meaning. Finally, we discuss video data and artifacts from an ongoing ethnographic project in Stockholm entitled "Children's relations to the city". Our analysis of the classroom video data from this project shows how concepts are not timeless transcendent abstractions, but part of an unfolding event and learning assemblage. Thus the article contributes to research on conceptual change in children, with particular focus on scientific concepts.