The study investigates secondary students' understanding of "orbital" and "electron cloud" concepts in different quantum contexts (for values of the ?principal quantum number n = 1 and n = 2) on the basis of their verbal and pictorial representations, evaluating also their consistency. Participants, which were 192 12th-grade…

Meaningful understanding of chemistry, among others, includes the ability of an individual to think simultaneously at macroscopic, submicroscopic and symbolic levels, and this presupposes the competence to translate between different types of chemical representations. In this study, we investigated 11th grade Greek students' and 3rd year…

The main objective of this work is to analyse the visual representations (VRs) of the microcosm depicted in nine Greek secondary chemistry school textbooks of the last three decades in order to construct a systemic network for their main conceptual framework and to evaluate the contribution of each one of the resulting categories to the network.…

In the present study, we test the effectiveness of a teaching intervention aiming at acquainting children aged four to six years with the concept of the sphericity of the earth and the causes of the phenomenon of day and night. The treatment comprised three units of activities that were developed collaboratively by a researcher and early years…