SUMMARY
Purpose and Significance: The constructivist learning approach aims at students’ combining their previous knowledge with forthcoming knowledge they acquire, and actively participating in their learning. In order to achieve this, it is important learning methods which help students actively participate should be used in learning settings. Among student-centered learning approaches, project-based learning is one of the learning methods based on the constructivist approach (Çiftçi & Sünbül, 2005). In the present study, project-based learning approach, which is a student-centered method, was used in the unit of “Solar System and Beyond: Space Puzzle”. Following the implementation, attempts were made to put forth the effect of project-based learning on student achievement. While there are studies on the effect of project-based learning on student achievement in literature, there has been no study on the project-based learning of the unit of “Solar System and Beyond: Space Puzzle”, which is within the scope of the Earth and Universe subject area, and motivated the researchers to conduct the study. It is thought that the findings of the study and practices in project-based learning will contribute to the literature regarding science education.