It is important that the teacher, in an inquiry learning gives his student sufficient thinking time regarding the teacher`s question and the child`s response. In an inquiry learning, it is essential that children should have an enough time to understand question fully and find out correct answers. The purpose of this study is to investigate an effect of science teaching, when Wait-time theory is applied, on the scholastic and thinking ability, thinking trend and scientific attitudes of elementary children. We could draw several meaningful conclusions from the study concerned with improving the effect of science teaching that changed from teacher centered teaching to children centered one.