Different grade levels students concept image related with solids objects (prism, pyramid, cone,cylinder, sphere)

The aim of the study is to determine concept image at different grade levels students? with solids objects ( prism, pyramid, cone,cylinder, sphere ).The study ,which is qualitative, is a fenomenology study. The participants of the study are 6 people in total, 3 students from each 9th and 12th grades at an Anatolian High School in İstanbul. The participants are chosen with the help of an achievement test among the students who attended the study and one of the participant was successful, one of them was avarage and one of them was unsuccessful.The data are gathered through semi-structured interviews and the documents which were used and written (such as notes) during these interviews and observations. Besides, in the interviews the participants are claimed to name the geometrical object models which are prepared beforehand through thinking aloud method and this makes up another data source.For the analysis of the data, content analysis, which are used in qualitative studies frequently, are applied. The data gathered from students are interpreted through fenomenographic method. The collected data are analyzed based on the concept image and the concept descriptions through the light of the literature.The results which we are have are the following:1.Some of the students construct prototype models about the solid objects. These models can be concrete or a geometrical drawing.2.The concept imege of the students related with the solids objects were identified with the their geometric drawings and geometrical object models which were used during the lessons.3.When the participants were faced to on area problems or volume problems related with solid object, the first thing they did was to tried to remeber the relation or formulas which then could use.In the last part of the thesis, some suggestions are given to the researchers who are studying on the mathematics education field and curriculum developmenters mathematic and geometry programmes and trainers.