The aim of this project is to study the quality of the discussions in groups of students during laboratory work. The project builds on a study of the role of communication in science classrooms with students aged 14-15 years. An intervention with role-playing for example reporting to another group is carried out to foster discourses that focus students’ use of science knowledge. The discussions have been divided into sequences. In each sequence the students are discussing one separate part of the lab work activity. A revised version of the SOLO-taxonomy has been used in the analysis of tape recordings from students’ discussions during lab work and from the reporting to another group. The students talk about the experimental procedure as well as the science content. In most of the groups the analysis show a long-term development towards higher quality mixed with unistructural sequences. During the reporting to another group the students describe the experiment using new knowledge and new concepts. Almost all the reporting groups use two or more concepts well integrated. The reporting to another group stimulates students’ discussions. The SOLOtaxonomy makes it possible to assess group learning and interaction in lab groups.