In this thesis the students' experiences of science classroom discussions are examined as well as the nature of their discussions and their ability to take different perspectives while working with socio-scientific issues (SSI). Student questionnaires concerning their attitudes towards school science and science in society, a paper-and-pencil test and focus group discussions have been analysed. The results show that students get to discuss during science lessons, and that they learn a lot from doing so. They also show that the SSI work has brought about a lot of discussions, to which students have a positive attitude. When investigating students' written and oral demonstrationsfewexamplesof argument-based discussions or ofperspective-taking ability were found. Based on these results I argue that in-service teacher training should be carried out, focusing how to organise SSI discussions so that they support students' development of concepts and of generic skills.