In Learning quantum mechanics, Fischler and Lichtfeldt report on a learning study, which combines an empirical study with a large student population from eleven courses with case studies of single students. In this paper they present an analysis of the development of 'dynamic networks of ideas' of two students, who are each given a different treatment during the course. The authors discuss the networks of ideas of
each of the two students both before and after instruction. The analysis clearly shows differences in the concepts acquired by the two students, as well as the increasing density and complexity of the students' networks after teaching.