American Journal of Educational Research, 2018, Vol. 6, No. 2, 96-103 Available online at http://pubs.sciepub.com/education/6/2/1 ©Science and Education Publishing DOI:10.12691/education-6-2-1 An Investigation of 8th Grade Students’ Knowledge on Geometrical Objects in Terms of Van Heile Levels of Understanding Geometry Fatih Karapınar 1 , Onur Alp İlhan 2,* 1 Erciyes University, Educational Sciences Institute, Mathematics Education 2 Erciyes University, Faculty of Education, Department of Mathematics and Science Education, Department of Mathematics Education *Corresponding author: oailhan@erciyes.edu.tr Abstract In this study, it was aimed to determine 8th grade students’ Van Hiele levels of understanding geometry and to examine their knowledge on geometric objects in terms of Van Hiele levels of understanding geometry. Survey model, a quantitative research design was used in the research. The study group consists of 161 students from three different schools of National Ministry of Education located in the districts of Melikgazi and Kocasinan in Kayseri province. The Van Hiele Geometry Test and the Geometric objects Achievement Test developed by the researcher was used to collect the data of the study. Some of the results obtained from the research are as follows: The Van Hiele levels of understanding geometry of the students who participated in the research were found to be lower compared to what they are expected to have at the present. There was a high correlation between the scores of the students on both tests. Significant mean differences were found among the schools in terms of both the Van Hiele Geometry Test and the Geometric Objects Achievement Test. When the data were analyzed by gender variable, there were significant differences in favor of girl students for both tests. Keywords: Van Hiele, geometric objects, geometric thinking, geometry, 8th grades Cite This Article: Fatih Karapınar, and Onur Alp İlhan, “An Investigation of 8th Grade Students’ Knowledge on Geometrical Objects in Terms of Van Heile Levels of Understanding Geometry.” American Journal of Educational Research, vol. 6, no. 2 (2018): 96-103. doi: 10.12691/education-6-2-1. 1. Introduction Mathematics has always been a guide in the history of humanity. As a result of development and progress of mathematics, science has advanced, science has accelerated technological developments, people's peace and prosperity levels have increased, their lifestyles have changed, and life expectencies has changed. People have overcome the difficulties they encountered in their lives through mathematics and have been guided their lives by mathematics. Many scientists have made different definitions from the past to the present day about mathematics, which has the power to change human life, knowledge, societies and technology. In [1] defined mathematics 1 as is a science that contributes to the development of talents and skills, helping people to free and objective thinking, increasing self-esteem, explaining the causes and consequences of living problems. For this reason, mathematics allows people to think freely in their lives. It enables them to overcome the difficulties they encounter and their life problems using their abilities. Mathematics 1 This work was supported by Erciyes University Scientific Research Projects Unit (project code :SYL-2016-6679) improves people's knowledge and skills and gives them confidence. Through mathematics, people are developing their self-confidence, developing objective and critical thinking skills, systematically and correctly thinking about problems in life, and establishing cause-effect relationships [2]. Mathematics is not just a discipline that made from shapes and symbols, from rules to operations. It is a network that has a meaningful integrity in it, a certain order, and a strong relationship. In addition, there is a strong relationship between mathematics and other disciplines, with other disciplines and everyday life. In this context, associative skill is a skill that allows a mathematical concept to relate to everyday life or mathematical concepts among themselves [3] (Ministry of National Education (MNE), 2013). Mathematics has important subject areas universally. National Association of Teachers of Mathematics (NCTM) emphasized that geometry is one of the most important and fundamental subject areas of mathematics and one of the conceptual building blocks [4] (NCTM, 2000). When we plan our daily life, we need geometry that exists in many stages of our daily life as we need mathematics when we make calculations about our life, from our home where we live, up to our mobile phone that we use. Geometry is a field of objects and shapes that have a very important place in human life. We often encounter