A Newsletter of the Center for Teaching Effectiveness
Spring 1996

Problem-Based Learning in a Large Introductory Geology Class

Allan M. Thompson,

An experiment in enhanced learning in large courses was carried out in GEOL105, a 130-student, introductory geology class, using a modified problem-based-learning approach. Four- and five-person groups investigated the potential and real impacts on students' personal lives of several important geological processes. Each process was introduced and developed via one or two traditional lectures. Over the next one to eight classes each group wrestled with a problem centering around the effects of the process. Analysis of the problem was done both during class time and out of class. Each group reached a position on the problem, and wrote a justification of its position that showed its analysis of the problem and evaluation of the evidence it collected.

This instructional approach targeted the needs of a specific audience. GEOL105 contained predominately non-science, liberal-arts students fulfilling a general-education group requirement in the College of Arts and Science. These students were not and will not be scientists, and have little need of traditional, content-driven, information-heavy science instruction. However, they will need to be logical and scientific throughout their lives, to evaluate evidence, and take positions on complex issues in every facet of their lives. Thus, the goals of the course were to (1) help students realize that the earth is alive, is constantly changing, and is capable of directly and forcefully impacting their lives; and (2) help students learn to deal with real-life situations which commonly involve rationally assessing risk and making significant decisions based on insufficient evidence in insufficient time frames. To realize these goals, breadth of geological-science coverage was traded for depth of understanding of what was covered. Improved abilities in openly discussing scientific topics, evaluating evidence, researching, digging for new evidence, proposing explanations, reaching positions, and assessing past and future impacts of geological processes, are skills they will need throughout their lives.

Group activities took two forms. One involved short-term, one or two class-period responses to situations that involved real-time geological events, such as the 1994 Northridge earthquake. These situations invited reactions both to past events and to future, hypothetical but clearly possible events. The primary intent was to enable students to separate emotional responses to the results of earth events from rational, evidence-based, "scientific" attempts to understand the causes of those events. An example: how would they handle the probability of dealing with major floods if they owned a large, profitable farm in prime agricultural land adjacent to the channel of the lower Mississippi River? This problem anchored the class investigation of rivers, and the group investigation consumed two class days and a lab period. The learning was about understanding erosion, deposition, and the dynamics of rivers, interpreting maps, appreciating the limits of humankind's attempts to control nature, evaluating risk factors, and weighing societal pressures and priorities against natural processes. The second group format involved a three-week-long, whole-class investigation of plate tectonics and the history of development of plate-tectonic theory. Twelve teams of two to three groups each researched various bodies of evidence that led to and were well explained by the new theory. Student groups presented their findings orally to the entire class. The material presented formed the basis for one of the five biweekly quizzes that constituted much of the course grade.

Student reaction to the educational philosophy and group format was consistently positive. A series of essay questions on the final exam revealed widespread, unexpectedly deep and broad understanding of the basic geological concepts and their direct relevance in their lives. I sensed strongly that most students had a better and more relaxed attitude about science than they had prior to the course. They were more rational and knowledgeable in how they dealt with evidence, and were more openly and willingly scientific in their approach to life.

Last updated Feb. 20, 1997.
Copyright Allan Thompson, Univ. of Delaware, 1996.