This study draws upon the framework for analyzing the discourse of a science classroom introduced by Mortimer and Scott (2003). It has been used for many studies before on high school youths, but never on adults. Therefore, this study focuses on the interaction between teacher and students in an adult education on high school level in physics, and how students can change the classroom discourse. Observations took place in two different schools for adults, in four different teaching groups. The result was analyzed by pattern of interactions, communicative approach, teaching purpose, type of student questions and their effect on the classroom discourse.