Problem-based learning (PBL) is an instructional strategy where students work in groups to solve an open-ended problem. It represents a shift from a teacher-centered approach where the teacher demonstrates and tests knowledge, to a student-centered approach where students discover knowledge through collaboration and hands-on problem solving. PBL cultivates critical thinking skills and student engagement. It allows students to develop creativity and independence by managing their own activities. PBL requires teachers to shift their goals from knowledge transmission to knowledge construction, and to focus on facilitating self-assessment over external evaluation.