In this study our purpose is to determine how the teachers are applying the constructivist approach in their classes by classifying the teachers according to graduated faculty, department and their years in the duty. Besides understanding the difference of the effects of constructivist approach and traditional education method on student success and knowledge sustainability. For the study the teachers are given likert type surveys and primary school 6th class students are used as final test and the repeat of the last test as data collecting tools. The study has been carried in 23 schools in Mersin City Center with 53 Science Teachers and two branches of Davultepe Ataturk Primary School in the Mersin City Davultepe district, where 52 students are used as 24 of them in a control group and 28 of them in an experimental group. The poll has been applied to teachers and the final test and same test after 15 days has been applied to the test students. While analyzing the final test data to measure the success and sustainability of the students test is used. (Contains 6 tables.)