Temperature phenomena are teached in primary education, but until recently, at that level of education, clarification based on the particle structure of the substance was avoided, thus creating space for the formation of a large number of alternative student ideas. Terms that describe the structure of matter such as molecule, atom, atomic bonds, etc are introduced in the upper grades (secondary education). Also, teaching contents about termal phenomena and processes are realized through teaching physics and chemistry, where the focus of learning is on macroscopic thermal manifestations without insight into the connection between the structure of a substance and its thermal (physical or chemical) changes. This paper presents an overview of research on the possibilities of the conceptual change models of thermal phenomena based on understanding of the structure of matter. Most research has shown that students at all levels of education, from preschool to university level, have retained alternative ideas about the concept of heat, which is the reason for questioning the effectiveness of teaching models that overcome the perceived misconceptions.

The method of interpreting thermal phenomena in the lower grades of primary school, which avoids explaining these phenomena based on the particle structure of a substance, gives room for pupils' alternative ideas. The aim of this paper is to determine the level of pupils' understanding of thermal phenomena in the lower grades of primary school. For this purpose we developed a test of knowledge of the following concepts: aggregate states of a substance, substance structure, temperature, heat, and heat conduction. The research was carried out in primary schools in the towns of Sombor and Kikinda and the sample consisted of 475 pupils. According to the obtained results, the lowest achievement, between 0% and 20% of the maximum points, is observed much more among the pupils of the first and second grades of primary school than among the pupils of the higher grades. In all grades the majority of the pupils had between 20% and 40% of the maximum number of points. There were no pupils with the highest scores. There was no significant statistical difference in terms of achievement bewtween the first and second grade pupils, nor between the third and fourth grade pupils, whereas this difference is statistically significant in other, higher pairs of grades (the final two grades had the highest level of achievement). The research confirmed that there is an insufficient impact of instruction on the level of understanding thermal phenomena among the pupils of the lower grades, which requires finding new approaches to teaching this type of content.