Understanding a Cartesian graph using the motion sensor

This paper shows the experimental results of a didactical activity conducted using the motion sensor. This MBL-tool (Microcomputers-Based Laboratory) allows to study rectilinear motion of bodies moving in front of it. In a fixed time interval the motion sensor reveals the distance of bodies from it and transmits the measures to a computer that visualizes the data in tabular and Cartesian representations. This research corroborates several works about the use of MBL-tools, according to which the use of the motion sensor allows the students to read, understand and produce kinematics graphs. Moreover our analysis shows that the students acquire these competence respect to graphs of other type also. Such research, born from a historical-epistemological analysis of the function concept, finds its theoretical support in the Embodiment Theory and Metaphorical Thought of Lakoff e Nuñez. The didactical activities, that will be described in this paper, were led by the teacher that, by his/her role of semiotic mediator, orchestrates and conducts the students towards the construction of their knowledge. In this paper, in particular, results of didactical activities developed in two Italian classes of Primary School (4th and 5th grade), will be showed. The experimental methodology references Brousseau’s Theory of Didactic Situations. It is based on statistical implicative analyse of the pre-test and the post-test and on a qualitative analysis of the lessons and of the open answers of the test.