In this presentation I try to show the epistemological and ideological framing of literacy practices in writing texts which concern concepts of science. The research was based on the retrospective analysis of two texts which were written in the activity of the Flexible Zone and on a projective interview with the teacher of the classroom. The analysis indicated that although both texts appear language markers which present two scientific phenomena as non-personal representations, the second text includes language and visual markers which present the ideas as human-mediated representations. Teacher's correction of these language markers as well as his interference in this text was considered as an attempt of regularizing the style as consistent with his language ideology. Finally, the view and the investigation of the scientific literacy are suggested as diverse practices of scientific literacy which pupils should be aware of through the ethnographic approach.