Discovering the dimensions of teaching the subject of subatomic particles in the tenth grade chemistry course, based on the PCK theory, with the Delphi method

The present article examines and identifies the dimensions of teaching in the subject of subatomic particles in the chemistry book, 10th grade, based on the pedagogical content knowledge model (PCK) of Magnuson, Krajcic and Burko (1999). In this research, two components "Knowledge of educational strategies" and "Knowledge of students' understanding of science" were selected and investigated. The research approach of this study based on mixed-methods sequential exploratory design is carried out using Delphi method in three rounds. The group of research participants is consisted of 33 chemistry teachers selected through “theoretical sampling” and then “Snowball sampling”. The first step involved semi-structured interview (round 1) and the acquired results of interview analyzed by “Open Coding” and “Axial Coding”. In the second round, a closed-answer questionnaire was designed according to the results obtained from the first round’s coding. Then the designed is provided for experts and the answers were investigated by means of Q factor analysis. In the third round, with the elimination of redundant questions, the edited questionnaire was assigned to the experts for the second time. Finally using the Q factor analysis, the following 8 dimensions were achieved: “Image symbolization"; "Learning activities"; "Practice of mathematical skills"; "Interactive-expository strategies of teaching"; "The origin of misunderstandings"; "Misunderstandings of the nature & stability"; "Resolving misunderstandings " and "prerequisites".