The use of controversial socioscientific issues in the STS curriculum demands understanding of the positioning of subjects, invited in the contempo raneity to experience a new relationship with science. In this article we review an episode of a high school's Chemistry class. Grounded in the Bakhtin's theory of enunciation, different voices were brought into the debate, when we focus on the discursive interactions about the greenhouse effect and global warming. Initially the students sho- wed to be unaware of the controversial nature of the topic as well as creating expec-tations according to a unique and true scientific positioning. Different rates of others' word's ownership, emotional and ideological accents were observed during the increasing awareness about the controversy.
Socioscientific issues; discursive interactions; science education