In most astronomy courses, we present the students with information about some topic, and then test their understanding of this topic using problem sheets. Problem Based Learning (PBL) is a teaching method that reverses this sequence. Students are presented with a problem first. The problem is usually a real-world one, and is far more complex and open-ended than those normally used in astronomy assignments. Students then have to go out and teach themselves (with the aid of the lecturer and tutors) whatever information is needed to solve this problem.
PBL was pioneered at Case Western Reserve University in the 1950s and at McMaster University in the late 1960s. It is now used by % of medical schools around the world, and is spreading to other (mostly professional) disciplines. Web links to a number of PBL based courses can be found in the reference list.
PBL was originally motivated by dissatisfaction with the performance of medical school graduates. It was frequently found that students who had graduated with even the highest grades were almost useless in real world situations. Students who obtained 95% for essays on subjects such as ``describe and explain the symptoms of and treatments for heart disease'' would flounder hopelessly when presented with a real heart patient.
Extensive research has shown that PBL can dramatically improve the ability of students to apply their learning in real-world situations, without degrading their performance in more conventional assessment (eg. Boud & Feletti 1991, Ryan 1993, Ostwald & Kingsland 1994, Little, Ostwald & Ryan 1995). PBL forces students to learn actively and to integrate their knowledge of different subject areas. It also teaches generic skills such as group work, defining problems, and self-directed study.
In this paper, two case studies of PBL exercises in undergraduate astronomy classes are presented. To the best of my knowledge, classical PBL has not previously been used in undergraduate astronomy courses, though many closely related techniques have been applied (eg. Francis & Byrne 1999, Duncan 1999).