Problem solving in physics in small groups. 
Contributions and difficulties
Léonidas Gomatos, 1996.
This research studies the verbal interactions between pupils who are solving physics' problems in small groups. The questions to be answered are the following : “How do students' representations of the problem evolve in a situation of group problem solving ? Can the teacher intervene in this process? 
Two experimentations have been conceived and realised in order to answer these questions : 
The first one concerns students of a tenth grade class of a senior high school in Athens. The students of this class solve problems in mechanics in small groups during a whole school year. The problems are open in that the conditions are not precisely specified and/or some data are missing. These conditions facilitate the expression of students' problem representations. These lessons are recorded in audiotape and then fully transcripted. 
An instrument of analysis is built in the purpose of analysing this material. It is based on the decomposition of the representation of a problem in mechanics according to four “dimensions” (interactions, space, time, movements) proposed by the “ PROPHY ” group in France in previous researchs. This filter of analysis allows to select the students' utterances which inform on problem's representation. It also serves as the criterion for characterising the types of evolution of the problem representation. Hence five kinds of evolution have been defined : 
•	evolution by completion (any time a new element is added) -evolution by modelisation change (when some element of the modelisation frame is changed) 
•	evolution by formulation level change (any time something already said at the level of facts is said again but using the physics concepts or vice versa) 
•	evolution by structuration (any time 2 or more of the four dimensions are used in the same utterence) 
•	evolution by replacement (any time an element of representation said before is changed by another different in some way) 
The following hypothesis have been corroborated by our analysis : 
•	The utterances of a student referring to the same topic are closely related one to the other and form chains. There is a continuity in students representations of the problem. The new elements can generally be explained by what has been said in the group. 
•	Students' representations of the problem in group problem solving situations become richer by the fact that multiple elements of representation are proposed during the discussion. 
•	This enrichment does not assure however the combination of elements. It seems that the interactions between students serve chiefly to move the attention from one element of representation to another and rarely to get structuration by taking into account several elements at the same time. 
The second experimentation focuses on testing a didactic proposition in order to overcome some of the difficulties observed during the first experimentation. This first experimentation showed that the two levels of formulation used by the students (facts and events on the one hand and physics concepts on the other hand) do not allow them to share the meaning of these representation elements. This proposition consists in a system of intermediate symbolic representations; intermediate between the factual and concrete level of formulation and the physical and mathematical one, in order to help the communication between students during there elaboration of the problem representation. The domain, this time, is elementary thermodynamics and more precisely the laws of perfect gases. 
The experience takes place in an eleventh grade class of a technical high school. The same group of students has been recorded during two phases of several problem solving lessons each. One of them is prior to the symbolism introduction, the other is posterior. The chief results are the following : 
•	The symbolic representations have been easily learnt. The students have employed them during the “posterior” phase but sometimes some teacher's intervention has been necessary to that. 
•	A certain cognitive progress has been observed during problem solving in the “posterior” phase in comparison with the “prior” phase. 
•	The use, by the students, of the symbolic representations proposed has rendered the dialogs between the students and the transcripts more “readable” for the teacher.