In this research, Purpose is to eliminate primary school student's delusions about concept of greenhouse effect and to study its effect on student's attitudes towards science. In the research, quasi-experimental study with prepost control group has been used. The research was performed with 34 primary school students in the state located in southwest part of Turkey. The experimental group consists of 18 students and the control group consists of 16 students. While POE method supported with PhET simulations is used in the experimental group, traditional teaching method is implemented in control group. In the research, greenhouse gas concept and science attitude scale as data collection tool have been used. Data obtained from the research has been analyzed with SPSS program. According to the findings from the research, Students have had much more information about greenhouse gas thanks to POE method supported by PhET. Moreover, POE method supported by PhET has positive effect on students' attitudes towards science.