This article is part of a two-year ethnographic study, in which the science instruction in a secondary education chemistry laboratory was studied in "Colégio São José", São Leopoldo, State of Rio Grande do Sul. The main purpose of this text is to show a microanalysis of laboratory events, aiming to contribute to the understanding of how the persuasion games, contacts and relations create the idea of a "nature" of things. In order to link the observed data theoretically, the articulation concept was used, according to the Cultural Studies of Science, focusing on two questions: How the activities are established and recognized in a science teaching laboratory? And how a proper and "natural" set of instructions are articulated in the laboratory? The study, although preliminary, enabled us to shed some light on practical activity in the school laboratory and to suggest a discourse for overcoming the understanding of those events as merely reproducers of ideologies and tacit knowledge of external science.
Articulation; Didactic laboratory of Chemistry; Ethnography
