Geometrical-mechanical artefacts for managing tangent concept

This workshop deals with the didactical use of geometrical-mechanical artefacts for managing tangent concept in vygotskian perspective and adopting Rabardel’s theory on instrumental approach. From this point of view, during the workshop activity, we present a pathway for the constructive use of the tangent to reflect with CIEAEM participants on suitable didactical practice for student of 12th grades and university level. Specifically the workshop deepens the kinematical properties of the tangent through a laboratorial didactic activity as prototype of the democratic approach to the problem solving. In particular we propose some "new" geometrical-mechanical artefacts presented according to the vygotskian perspective to mediate the meanings related to machines embodied knowledge. From this point of view the proposed artefacts constitute the link between the subtended mathematical content and the laboratorial activity defined on a democratic practice in the classroom.