While there is evidence that collaborative learning consists largely of group-level practices, there has been little analysis and description of these processes as such; learning has generally been studied at the individual unit of analysis. Our research, in contrast, focuses on describing the interactional small-group practices that take place in learning contexts. This paper considers these practices and how they work together to form the foundation for effective collaborative learning activities. It analyzes collaborative learning activities in a paradigmatic CSCL setting to discuss such small-group practices as: resolving cognitive conflict, pursuing inquiry, maintaining a group problem space and coordinating multiple modes of reasoning. These have broad implications for foundational issues of temporality, indexicality and group cognition.