There is consensus that physics is a hard discipline to understand for most of the Brazilian students. Because of this finding, several researches have been developed to investigate the causes and possible solutions for this problem. Among the several thematic possibilities in this field, there are investigations about the use of Information and Communication Technologies, for science teaching. In this paper, we present the results of a qualitative research which has the main goal of identifying the occurrence of collaborative learning mediated by a Virtual Learning Environment (VLE) called Laboratory of Collaborative Learning of Physics (LAFIS in Portuguese acronym). We built this VLE based in Vygotsky’s theory, believing that it may favor the interaction and collaborative participation between students mediated by the teacher. In this environment, the students interact with each other and with the teacher by a chat in order to solve a given physics problem. We analyzed the virtual interactions that happened in classroom based in microgenetic analysis. The analysis of records enabled us to find evidence of the students learning and development while they try to solve the problems. We verified the importance of the interactions for solving the proposed questions, as well as how the teacher mediations should be conducted in order to favor this process.