La rappresentazione della natura particellare della materia come aiuto del Problem Solving

The abilities to perform formal operational reasoning of the students that arrive at the university are quite low, as it results from a study connected with the particulate nature of matter. In literature there are so many diagnostic studies that emphasize students’ difficulties with so few effective proposals for the problem solution. The students’ difficulties have been diagnosed using the Friedel-Maloney’s test. Students find some difficulties in translating sentences into algebraic equations. Therefore, two directions can be pursued to resolve this problem. We need to offer an easy way to represent the problem and an effective way to make the proportional relationships easy for them. The recourse at the stoichiometric ratios derived from the representation of the particle nature of matter used in a step by step approach can be the response. The approach here suggested dramatically improvements of the student’s performance in problem solving.