Abstract

The aim of this research was a) to detect primary students’ initial conceptions about dissolution, b) to help students develop and relate appropriately representations issued from the empirical and microscopic levels, using an interactive computer simulation, c) to study students’ conceptual evolution during an innovative teaching approach concerning the concept of dissolution. The sample of this research consisted of 61 primary students (aged 11-12). Thirty two (32) students formed the experimental group and 28 the control group. Experimental students worked for 4 hours in small groups carrying out simple laboratory experiments and activities and for 4 additional hours in the computer, using particulate models of matter for the representations of solid, liquids and gases, as well as for the dissolution of different crystalline substances. Before and after teaching, all students answered the same written questionnaire. Research data is issued both from the students’ answers to the questionnaires, as well as from their remarks, drawings and conclusions written in their worksheets. Initially, some students did not understand matter conservation when salt or sugar is dissolved into water, they confused dissolution and melting and they did not have mental representations of the phenomenon in the microscopic level. After teaching, their initial conceptions improved substantially and they were able to apply a particulate model of matter in order to represent and explain dissolution.