Adaptation of acquisition of secondary school mathematics course with interdispliner STEM approach and analysis of activities' effectiveness based on this

The study, which aimed to adapt secondary school mathematics course outcomes with an interdisciplinary STEM approach and examine the effectiveness of activities based on this, was carried out using a multi-stage mixed method design. The study consists of three stages, including determining the concepts in which the interdisciplinary approach can be used with the Delphi method, the planning of the teaching with the determined concepts, and the implementation and evaluation of the planned education. The first stage was carried out with the Delphi method. Working together with experts consisting of academicians and teachers, whose total is 84, it tried to determine the concepts that could be interdisciplinary in the curricula of the relevant courses. In the second stage, the teaching plan was developed by using the concepts determined in the first stage together with the teachers. The teaching plan prepared according to the explanatory sequential mixed design was applied in the third stage. The application was conducted in a pre-test and post-test quasi-experimental design with 47 students at the 7th-grade secondary school level. At the end of the application, students' opinions were taken. Mathematics academic achievement tests, STEM attitude scales, and multidimensional 21st-century skills scales were used as quantitative data collection tools. The researcher developed the academic achievement test. The STEM attitude and multidimensional 21st-century skills scales were taken from the literature. Validity and reliability studies of all data collection tools were carried out. As a qualitative data collection tool, the researcher prepared a semi-structured interview form and finalized it after the expert opinion and pilot application were used. According to the study results, there was a statistically significant increase in mathematics course academic success, STEM attitudes, and 21st-century skills in favor of the experimental group students of the applied teaching. Active participation in education, which is involved in line with the student's opinions, is a teaching that increases student interaction, provides efficient course content with its components, and contributes to cognitive, affective, and skill.