From scientific knowledge to learned knowledge: investigation of the concepts about gases through didactic transposition in higher education

Didactic transposition theory examines entire progression that scientific/academic knowledge produced by scientists becomes learned knowledge constructed by the learners. There are four types of knowledge under the didactic transposition theory; scientific knowledge, knowledge to be taught, taught knowledge, and learned knowledge. The transition between different types of knowledge and learning and teaching processes between instructors and preservice teachers were investigated in detail for the concept of "Gases" in higher education General Chemistry-I courses. The design of the study was constructed as case-study to acquire detailed information about the transposition. The study was conducted in two dimensions and in three stages. The first stage was to investigate didactic transposition process of the concepts about "Gases" in terms of two instructors teaching General Chemistry-I course at the same department in different class. The second stage was to investigate didactic transposition process of the concepts about "Gases" taught by one of these instructors in General Chemistry-I course at different departments. To investigate both stages, three step process given in the below conducted: In the first step, to determine knowledge to be taught, the concepts which instructors hold was tried to be determine. Therefore, semi-structured interviews were conducted with the instructors to determine the didactic preferences of the instructors about the concepts that they would choose for the content and reasons for their preferences. At the same time, document analysis was used for the sources/ references that the instructors stated in the interviews that they benefit and used in the course. In the second step, to determine taught knowledge, the courses about "Gases" taught by the instructors were observed and content analysis was carried out to analyze this observation data. Also, at the end of the teaching process, it was tried to reach the taught knowledge through semi-structured interviews carried out with pre-service teachers. The third step was the last step to determine learned knowledge of pre-service teachers. In this step, Diagnostic Form and Word Association Test was implemented as pre test and post tests to reveal the pre-service teachers' existing knowledge and learned knowledge about "Gases". At the end of the process, to determine how the pre-service teachers made this transposition, semi- structured interviews were carried out. It was concluded that didactic preferences of the instructors was highly effective on taught knowledge. Also, it was observed that the "knowledge to be taught" of the instructors directly and indirectly affected "the taught knowledge". And it was determined that the learned knowledge of the pre-service teachers was closely connected to "taught knowledge" with individual characteristics. In the light of the findings, it was concluded that the interaction between the instructor and pre-service teacher affected positively the learned knowledge of pre-service teachers. It was also found that pre-service teachers' pedagogical content knowledge and hidden curriculum is effective on taught knowledge and therefore on learned knowledge.