Contribution to Learning-Teaching of the Atom Concept at Junior High School
CHARLET-BREHELIN, Danie, 1999
key-words: atom, teaching-learning, concept, conception, modelling activity, particulate model, history.

This research on science education is in une with issues that arise with the atom concept. In fact, this concept forms the core of the conceptual network upon which chemistry is built and is problematic for teaching and learning as early as junior high school.
In the first theorical part, different analyses essential for didactic research are carried out:
- historical and epistemological analysis aimed at understanding the slow development of the atomic concept from ancient Greek times until present,
- analysis of the works of child psychology specialists (Piaget, Vygotsky) and their impacts on educational methods,
- analysis of modern educational theories and the necessity to take students’ conceptions into account,
- analysis of the status of models in different scientific theories and classroom problems raised by modeling activities.

In the second part, two experiments performed in class are reported:
- evolution of conceptions of the atomic concept by pupils at different junior high school levels,
- implementation of two pedagogic sequences on modelling activities (i.e. model building) focusing on the particulate model (13-14 years), and atomic structure (14-15 years).

Finally, after an analysis of the results, we propose a leamning sequence based on a modelling activity that can be used immediately without any modification of current 5th 4th 3rd level programs in French junior high schools.