The design of a teaching sequence on axial symmetry, involving a duo of artefacts and exploiting the synergy resulting from alternate use of these artefacts

This paper presents a teaching sequence, addressed to 4th grade students, aimed at the construction/conceptualization of axial symmetry and its properties in which a crucial role is played by a duo of artefacts. This consists of a concrete artefact and a virtual artefact which address the same mathematical content. According to the Theory of Semiotic Mediation, both the artefacts have been chosen for their semiotic potential, in terms of meanings that can be evoked by carring out suitable tasks involving their use. The design of the teaching sequence is developed with the purpose of exploiting the synergy between the artefacts, in such a way that each activity boosts the learning potential of all the others.