A Cross-Age Study of the Development of Understanding of the Concept of Matter at the Macroscopic and Sub-Microscopic Level

Abstract

This cross-age study aimed to provide an insight into the development of stu- dents’ understanding of the concept of matter, at the macroscopic and sub-microscopic level of chemistry knowledge. The research sample encompassed 121 students aged 14 years, 108 stu- dents aged 16 years and 112 students aged 19 years. All students completed the test comprised of five pictures and five schemata which depicted a monatomic/diatomic element, a compound and a homogeneous/heterogeneous mixture, at both of the levels. In this way, it was examined whether the selected age groups exhibit significant differences in understanding of elements, compounds and mixtures at the above-mentioned levels and whether the depth of understanding of these concepts at the macroscopic and sub-microscopic level significantly changes with the age of students. Research results indicate that all three age groups have a significantly better understanding of diatomic elements, compounds and heterogeneous mixtures at the macro- scopic, in comparison to the sub-microscopic level and a significantly better understanding of monatomic elements and homogeneous mixtures at the sub-microscopic, in comparison to the macroscopic level. Overall, a significant improvement of understanding of the concept of matter, at each of the levels, was only observed between the ages of 14 and 16.