Examination of Seventh Grade Students' Van Hiele Geometric Thinking Levels and Their Mistakes on 'Quadrilaterals'

Abstract

In this study, it was aimed to examine seventh grade students' Van Hiele geometric thinking levels and their mistakes on 'Quadrilaterals'. The research was conducted with ten seventh grade students and the case study model, one of the qualitative research methods, was used. The Van Hiele geometric thinking levels test developed by Usiskin and the diagnostic test developed by Başısık were rearranged and administered to the students. According to the research findings, seventh grade students have misconceptions about diagonal, height concepts and special quadrilaterals. One of the most important of these is that the square positioned on one corner cannot be recognized by students at the analysis level, but is recognized by students at the visualization level. Students at the analysis and visualization levels have different misconceptions regarding the trapezoid. While there is a misconception that all side lengths must be different from each other as a condition for being a trapezoid, there is also a misconception that having four sides is sufficient. Another one is related to the concept of diagonal. There is a misconception that shapes with equal side lengths also have equal diagonal lengths. While no errors or misconceptions were encountered in students at the informal level, misconceptions were encountered in students at the analysis level, and more errors were encountered in students who were visualization and could not be assigned to any level.