Construction of a concept at the interface between computer science and elementary algebra in junior high school: the variable in a parameter role ; Construction d'un concept à l'interface entre informatique et algèbre élémentaire au collège : la variable dans un rôle de paramètre ; Construction d'un concept à l'interface entre informatique et algèbre élémentaire au collège : la variable dans un rôle de paramètre: Enquête épistémologique et analyse de l'activité des élèves à l'aide d'une captationautomatisée de leurs actions de programmation dans une situation de généralisation demotif informatisée

Algorithms and algebra, and more generally computer science and algebra, are reputed to be frameworks that display a certain proximity. An epistemological study of the concepts at the interface between these frameworks allows us to emphasize the importance of the variable in the role of parameter, necessary for generalization, but also a potential epistemological obstacle. In this role, the traditional opposition between computer variable and mathematical variable is overcome in favour of a semiotic equivalence. In order to identify the conditions under which students construct the necessary existence of the parameter and its representation in a certain semiotic register (algebraic or computerised), we study a situation involving the computerised generalisation of a pattern, which is supposed to enable the construction of this concept.In order to analyse the dynamics of the students' activity at a fine level of granularity, we designed a computerised device to capture the students' programming actions in the block-based graphical programming environment used for the situation under study (Snap!). Analysis within the Problem-Based Learning framework, based on the programming traces of two 4th year classes, shows the need for pupils to experience the fixed-variable tension of the parameter, between the uniqueness of the symbol and the multiplicity of its possible denotations. Furthermore, the facts constructed by the pupils to pose and construct the problem of generalisation are eminently linked to the sub-problems they pose themselves, and this leads us to identify the potential interest of caricatures in situations for learning computer science concepts. ; Résumé : L’algorithmique et l’algèbre, et plus généralement l’informatique et l’algèbre, sont réputés être des cadres affichant une certaine proximité. Une étude épistémologique des concepts à l’interface entre ces cadres nous permet de souligner l’importance de la variable dans un rôle de paramètre, nécessaire pour la généralisation, mais aussi ...