The aim of this research is to examine the effects of interactive group work and using different active learning methods leaning against constructivist theory on students’ achievement and their way of constructing the knowledge by using the unit ‘What are the things present in our body? How do we perceive our environment?’ which is placed in 6th grade of science lesson in elementary education. In this research, the experimental group was taught by active teaching methods and techniques and cooperative learning which was based by constructivist theory. However the control group was taught traditionally. Before and after the application, each group was given achievement tests designed by the researcher. An interview was made with both of the groups in order to understand how the students construct the knowledge. Besides, each group received a last test of two-tier questions after the application. Finally, the effects of constructivism on the students’ achievement and their way of constructing the knowledge were examined and it is seen that there are significant differences in favor of experimental group.

Keywords: Constructivism Theory, science teaching, teaching models, cooperative learning