Background:
This study examines how the use of a science inquiry activity in an environmental socio-scientific issue (SSI) impacts pre-service teachers’ argumentative practice in two ways: social negotiation and epistemic understanding of arguments.

Material and methods:
Twenty pre-service science teachers participated in this study as a part of their science methods class. Small group discussions, while participating in an SSI debate, before and after engaging in a science inquiry activity, were collected as a main data source. The data were analyzed by an analytic framework adapted from both Toulmin’s (1958) model of argument structure and Walton’s (1996) reasoning scheme.

Results:
The results indicate that the use of a science inquiry activity during SSI debate not only affects the teachers’ social negotiation patterns, but also enhances their epistemic understanding.

Conclusions:
This study suggests that incorporating a science inquiry practice into an SSI debate has the potential to improve students’ disciplinary engagement and the quality of their argumentative practice.