Instrument Within the extend of the study, a concept test was developed and applied to determine 7th grade students’ understanding of measurable properties of substance, heat and temperature, pure substance and mixture, particulate nature of substance, elements and compounds, elements and symbols, and structure of atom which are the basic concepts of chemistry. During the process of developing the test, learning objectives determined by Ministry of National Education were analyzed, revised and classified according to Bloom’s Taxonomy (Krathwohl, 2002). An item pool with 53 multiple choice items was created in accordance with these objectives. Test items consist of 4