This paper presents the methodological lineaments that guided a research study designed to explore the language of a physics teacher through its discourse. It tries to analyse, in the teacher's discourse, the space assigned to the contents and procedures as basis to the understanding of the material environment and the conceptual organizations in a technology class. The records were made in technology classes, at High School N° 10 of the city of Tandil, by one of the authors who observed these classes during six months. The objective here is to provide the foundations of the methodological decisions that permitted to carry out the research in the ethnographic framework.