The data consists of transcribed recordings of classroom dialogues in two grade 11 classrooms during two 4 hour science lessons. All data is in Norwegian. The data was collected during teacher planned ordinary science lessons at a upper secondary school. Data were collected in 2017 using whole-class video recordings (camera pointing towards the front of the classroom from behind) and audio recordings of group discussions of five groups in each class. Recordings from each lesson were transcribed verbatim, and the data set in this database consists of these transcriptions.