PROBLEM-BASED LEARNING IN UNDERGRADUATE EDUCATION : A SOPHOMORE CHEMISTRY LABORATORY

Problem-based learning (PBL) is a pedagogical approach based on recent advances in cognitive science research on human learning (1). A PBL classroom is organized around collaborative problem-solving activities that provide a context for learning and discovery. PBL has been used in medical schools to enhance the development of clinical reasoning skills and to promote the integration of basic biomedical sciences with clinical applications. Medical education literature is replete with articles on the practice and evaluation of PBL methods, but there is very little published on the application of PBL for science education in undergraduate settings. A recent paper by Dods in this Journal describes a very interesting application of PBL in a biochemistry lecture course (2). There have been some presentations at recent ACS conferences describing the application of PBL in chemistry courses (3, 4 ). Other problembased approaches to pedagogy have been described by Wenzel and Hughes (5, 6 ). These approaches are similar to PBL in that students learn in the context of an authentic problem solving experience. This paper describes the implementation of PBL pedagogy in an undergraduate classroom setting. The author provides a brief description of PBL philosophy and PBL protocols, guidance on how to choose and design a PBL problem and integrate it into the curriculum, and a description of a laboratory course in which PBL has been successfully implemented. What Is the PBL Process Like in the Classroom? In a PBL classroom, students learn in the context of a problem to be solved. The responsibility for learning is with the students, not with the facilitator. There are five well-defined stages in the PBL process: introduction, inquiry, self-directed study, revisiting the hypotheses, and self-evaluation. In the introduction stage, students are presented with a succinct problem statement that gives them a well-defined role that they can adopt. In the next stage, inquiry, the facilitator guides the inquiry process so that students elicit data about the problem, look for additional information in the materials provided (the inquiry materials), and write down the topics that they need to look up (the learning issues). The facilitator demonstrates how to organize the problem-solving process into distinct steps. The information generated in the discussion is entered in one of four categories: Facts, Hypotheses (Ideas), Learning Issues, and Action Plan. At the end of the first session, students commit to one of the many hypotheses and select learning issues that they will pursue independently. Having committed to a hypothesis and chosen learning issues, students look up information from different sources—with some initial guidance—in the self-directed study stage. After their self-directed study, students evaluate the resources they used and share information with their colleagues during the revisiting the hypotheses stage. They reconsider their hypotheses with the benefit of the new information they have gathered as they try to solve the problem. Finally, during the selfevaluation stage, students are asked to evaluate their efforts and their groupmates’ efforts as problem solvers, as self-directed learners, and as members of a group and to discuss these evaluations with their group. During all these stages, the instructor facilitates the process by listening to the group’s discussion and probing their understanding, interceding appropriately when they proceed to apply their science knowledge (7, 8) and to model the problem-solving process.