The effect of argumentation on students' conceptual change about the particle model of matter uni̇t

This study was carried out with 7th grade students in a secondary school located in Kocaeli-Gebze district within six weeks during 2017-2018 school year. As part of this study, it is aimed to develop students' conceptual changes about the subject in a positive manner by developing sample activities specific to the argumentation-based education. The researcher carried out the study with 95 seventh grade students (46 girls, 49 boys) studying in four branches of the school where she was employed. At the beginning of the study, students' misconceptions have difficulty in understanding about the the particle model of matter, elements, molecules, compounds, substance, püre substance and mixtures was determined by using formative assessment questions. In this context, convenience sampling method was used in the study. Then, two of these four branches were selected randomly, 24 students in the first branch were assigned to the experimental group and 24 students in the other branch were selected to the control group. While, the argumentation was applied In the experimental group, activities take part in the 2018 Science Course Curriculum was performed in the control group. At the end of the study, it was determined how the conceptual change was realized in the experimental and control groups with formative assessment questions. In addition, the experimental group' the skills of the argument-building was also examined. In this study, qualitative and quantitative analysis techniques were applied together using a pre-test/post-test with control group experimental design and interviews and document analysis methods. In the analysis of formative assessment questions, grading key developed by Karataş (2003) was used. "Argument Evaluation Grading Key" developed by McNeill and Krajcik was used to evaluate argument-building skills. The quantitative data were analyzed using descriptive statistics, dependent and independent sample t-tests, Cohen's size effect, with the SPSS 15.00 (Statistical Package for the Social Sciences) program at the .05 significance level. Also, the qualitative data obtained from the students' arguments was evaluated with content analysis. As a result of the study, it was determined that the students had some difficulties about particle model of the matter unit and there was a positive effect in the conceptual understanding level of the students with the argumentation-based teaching in which organized according to these deficiencies. Although the students generally make arguments at basic level, it can be said that they contribute positively to their conceptual development. In order improve the level of the arguments, teachers should encourage students to think scientifically and to become more active in the classroom. Key words: Argumentation method, science education, particulate structure of matter, conceptual change.