Results of a study on the acquisition of the field concept in physics by high school and college freshmen students, carried out under the framework of Vergnaud's conceptual fields theory, are presented. The aims of the study were to explore the links between students' cognitive structure and the formal structure of the field concept in physics, and to describe their levels of conceptualization of such a concept. Research findings confirm the potentialities of Vergnaud's theory to understand and explain the learning process of this basic physical concept. The links would manifest themselves in the use of symbolic representations and in a partial explicitation of some meanings that would suggest the presence of some operational invariants students use to cope with situations and problems that require an acceptable scientific conceptualization. However, a clear absence of scientifically accepted operational invariants was observed. About 92% of the students were located at the lowest level of a 1 to 3 conceptualization scale defined in the study, where 3 corresponds to the recognition and partial acquisition of meanings of the field concept. This low level of conceptualization correlates with poor performance in the following categories of analysis : operational (17, 6 %), written expression (17,3%), symbolic representation (13,6%), and problem solving (5,5%). These results agree with Vergnaud's theory that states that a low level of conceptualization corresponds to lower levels of explicitation of operational invariants and their representations, and predomination of procedural aspects over conceptually richer predicates.
field concept in physics; concept learning; Vergnaud's theory of conceptual fields
