Gestures: A Mode of Conceptualization in Science Gestures: A Mode of Conceptualization in Science

International audienceProblem Since the late 1970's there has been a lot of research to identify students' conceptions about physics (e.g., Pfundt & Duit, 1999). Now, more recent studies attempt to identify the factors that support the evolution of students' initial knowledge towards scientific knowledge. Among the studies of conceptual change (Posner, Strike, Hewson & Gertzog, 1982), we belong to small group of researchers that follow learning and change processes in real time, that is, "the data is collected continuously during the learning process. The aim is to capture and be able to describe the entire process" (Niedderer, 1992). To follow learning and change processes, we need to model the students' thought and use the definition: "knowledge" is a set of ideas, (which could be contradictory between themselves or not), each one can be applied in several material situation, these situations represent the domain of validity of one idea (Balacheff, 1999). We reconstruct a student's ideas on the basis of his/her actions, especially, verbal productions, communicative gestures, and manipulations of experiences. In this paper, we document how students' ideas evolve in a teaching sequence, specifically designed with the aim of understanding how students learn. The ultimate goal was to improve the teaching of gases at the level of higher secondary school (10 grader, 15-16 year old). Our general research question was, " How do the student's ideas evolve in our teaching sequence on gases? " To follow the student's conceptualization, we will focus on the role of communicative gestures, especially on the synchronization between speech and gesture (Roth, 1999). Background Communicative gestures have been classified into different types including those of deictic (pointing), iconic, metaphorical, and beat nature (Kendon, 1985; McNeil, 1992; Scherer, 1984.). Deictic gestures "point" out some aspect of the context. Iconic gestures and the entities they stand for are characterized by mapping relationships such that both be understood in terms of the same topological features. For an example, a scientist might outline a graph by following it using her finger, and thereby highlights the shape of its line. In a similar way, metaphorical gestures provide a visual expression of a metaphor, even though the concept or idea may be abstract. Finally symbolic gestures function as independent signs and obtain their sense through shared social conventions (raising of middle finger to signal an obscenity) (Roth 1999). In this study, we will focus only on iconic and metaphoric gestures, especially their synchronization with speech, because together, speech and gesture constitute a good indicator of knowledge (Goldin-Meadow, 1997)