Proofs, Semiotics and Artefacts of Information Technologies

Abstract. Recently, as part of a larger research project, we carried out a long-term teaching experiment in the 9th and 10th grades of a scientific high school. Assuming a Vygotskian perspective, we focused on the social construction of knowledge and on semiotic mediation as accomplished by the teacher through the use of cultural artefacts. This paper discusses on some results from the teaching experiment with the aim of clarifying the role of information technologies in introducing students to a theoretical perspective. The first part of the paper is devoted to introduce the construct of semiotic potential of an artefact. This construct is part of a model that was developed as result of the teaching experiment. Such a model aimed to describe the functioning of semiotic mediation in teaching – learning processes centred on the use of an artefact. The second part is devoted to discuss two examples concerning the use of two different artefacts. The first example addresses the issue of identifying the semiotic potential of a particular dynamic geometry environment, Cabri. The second example addresses the issue of designing a particular artefact as a tool of semiotic mediation with the specific educational goal of developing the idea of Algebra Theory. In both case I will discuss on the common feature of exploiting the semiotic potential of computer-based environments.