This article is results of the research carried out between the years 2000 and 2001 in a Chilean high school, with the objective of studying the role of the computer in teaching. The focus was to understand and to describe the technologies used for teaching in high school, identifying them and seeing how they operate, their possibilities and limitations and the contradictions that may emerge as part of the natural development of the activity. The approach used for the methodological design was the cultural-historical Activity Theory, this being the reason why the investigation was structured in two phases: (a) the cultural-historical reconstruction of the teaching activity and (b) the empirical description of pedagogical practice in a specific context.
