Abstract
This thesis deals with the concept of a field, in particular magnetic and gravitational ones at two school levels: primary and secondary ones.
From the analysis of previous research and a deep content analysis, we focused this work on some specific hypothesis of research, based on two principal research questions: 1) can field lines representation facilitate a more global vision of the field (as opposed to the local one) and a differentiation of the different types of field by their maps; 2) can the differentiation of polar and dipolar fields allow students to identify the specific properties of the different types of field.
The research hypothesis are presented in two groups, one for each school level, and they are specified in sub-hypotheses, and put to the test. They are mostly related to the distinction between the two effects of magnetic interaction (attraction and orientation), to the conception of magnetic field lines as “lines of orientation” (and not lines of force), to the distinction between unipolar and dipolar field.
In two preliminary studies, at primary school, we identified some potentialities and difficulties of this approach at this school level. In particular: the source of magnetic field is more easily recognised by children than that of the gravitational field, in the magnetic interaction the attraction effect is dominant with respect to the rotation effect, and finally children are able to differentiate the shape of magnetic and gravitational fields, but they have some difficulties to pass from the difference between the shapes of field lines to the difference between the actions of the two sources.
On the basis of these two preliminary studies at primary school, we designed two teaching-learning sequences about magnetic field, at primary (9-10 years old) and secondary (18-19 years old) school levels.
At primary school level, field representation by field lines was accessible at a large part of the children. They where able to identify magnetic field lines with lines of orientation (and not of force) and to differentiate between the maps of the two fields (magnetic and gravitational), but we still observed the difficulty to pass from the difference between the maps to the difference between the actions of the two sources, whereas the obstacle “attraction is dominant”, found in the preliminary researches, seemed overcome.
At secondary school level, students used the shape of field lines to differentiate polar and dipolar fields. Field lines were used also to identify the analogies between fields. In this school context, the results of the analysis of the sequence and of the post test show to which extent – in fact: large – the approach proposed helps students consistently progress toward an understanding of the concept of a field. They also suggest guidelines for future research.
Reference List
BRADAMANTE, F. & VIENNOT, L. (2007) “Mapping gravitational and magnetic fields with children 9-11: relevancy, difficulties and prospects” International Journal of Science Education Volume 29, Issue 3 February 2007 , pages 349 – 372
BRADAMANTE, F. & VIENNOT, L. (2005) “Fields as a mapping of space: An accessible conceptual target and tool in primary education?” Proceedings ESERA conf – Barcelona
BRADAMANTE, F. FEDELE and B. MICHELINI, M. (2005) “Children’s spontaneous ideas of magnetic and gravitational fields”Proceedings ESERA conf -Barcelona
BRADAMANTE F. & MICHELINI M. (2005) “Cognitive laboratory: gravity and free-fall from local to global situations”, Girep book of selected papers, Lubiana 2005.
Corespondence
Prof. Marisa Michelini
Unità di Ricerca in Didattica della Fisica (URDF), Università degli Studi di Udine
Prof. Laurence Viennot
Laboratoire de Didactique des Sciences Physiques (LDSP), Université Denis Diderot (Paris 7)
Francesca Bradamante
e-mail: fbradamante@hotmail.com
tel: 00393200488202
Unità di Ricerca in Didattica della Fisica (URDF), Università degli Studi di Udine
Via delle Scienze 208, 33100, Udine , Italy
Laboratoire de Didactique des Sciences Physiques (LDSP), Université Denis Diderot (Paris 7) Case 7086 – Campus Paris Rive Gauche – 10 rue Alice Domont et Léonie Duquet, Paris, France
