Project-based learning is an inquiry-based teaching method which utilizes student projects as the primary vehicle for delivering and reinforcing content, course goals, objectives and learning experiences. While many teachers include projects in their courses, not all teachers practice project-based learning. Traditional approaches to teaching use didactic methods where the teacher assumes the primary role of knowledge provider. The teacher delivers lecture-based content to the students who spend most of the instructional time listening and recording notes. Project-based learning, in contrast, allows the teacher and student to assume the role of knowledge provider and the learning is reinforced through student or team work on a project associated with and driven by the content. This manuscript presents a reasoned list of the principles of project-based learning, as well as a comparison of project-based learning to other student-centered learning approaches.