In this paper we shall analyze a conceptual activity elaborated by adults in a physics classroom context, related to the Newton's First Law of Motion. The data comes from writing activities carried out by the students, in which they debate about the possibility of the Earth motion using concepts of inertia and relative movement. The analysis, founded in Bakhtin's Philosophy of Language, is focused on the contents and com positional structure of the students utterances, in order to examine the dialogs between their own words and the "alien words" of school science. We show some methodological procedures related to the selection and analysis of such texts. For the analysis we use some kind of relationships between alien words and the subject: 'agreement1 and 'interlacing', drawn on the notions of 'quoted discourse' and 'hybrid construction'. The results indicate a larger 'agreement' position of the adult students with the school science discourse.
Conceptual development; appropriation; discourse analysis; Bakhtin; adult education