In a moment of collaboration lasting 17 seconds in a middle school classroom, a small group of students learned how to conduct scientific experimentation using a particular artifact. They made this knowledge visible for the group, repairing confusions and establishing a shared understanding. A micro discourse analysis of this moment illustrates the complexity of collaborative learning and of its analysis. To make learning visible as researchers, we deconstruct the references within the discourse. The meaning that the participants constructed is analyzed as constituting a network of semantic references within the group interaction, rather than as mental representations of individuals. No assumptions about mental states or representations are required or relevant to the researcher's analysis. Collaborative learning is viewed as the interactive construction of this network. Shared understanding consists in the alignment of utterances, evidencing agreement concerning their referents.