One aim of science teaching is to prepare students for civic reasoning about socioscientific issues. This study analyses student conversations about socioscientific issues organised with inspiration from Harkness-teaching. Conversations were based on students’ own questions and focused on collaborative exploration. Categories were constructed to describe how students practiced the model of conversation and what content they applied as frames of references in meaning making. The results show that the students engaged in explorative discourse, where it was possible to invite each other, be open with one's uncertainty and to introduce new perspectives. Alongside science, social science and ethics, students used historical and international perspectives, perspectives of other humans, general opinions and personal experiences as frames of reference. The categories were employed to interpret conversations in terms of Bildung, suggesting that the conversations could instantiate Bildung-oriented teaching in practice.