Messenger - Vol. 3, No. 3, Page 9 Spring 1994 On Research Science classes focus on problem-based learning It's Friday afternoon, and a call comes in concerning an automobile accident that just occurred. It is a two-car collision with possible speeding, possible running of a stop sign and a possible fatality at the scene. Sounds like a job for the local police. But, this case was solved by the Honors Physics class. This example, along with many others, is part of a new approach that Barbara Duch, teaching consultant from the Center for Teaching Effectiveness, is using to teach physics to pre-med and pre-physical therapy majors, as well as other science students. Duch explains that this class is structured around a problem- based style of learning, grounded in the premise that students learn concepts more effectively in connection with real-world problems. The class is group-oriented. Students cooperate in groups of four to solve problems and to answer each other's questions. Group effort enables students to help one another work through the problems so that they eventually uncover the pertinent information themselves. One or two problems in the hour exams are solved in the group, while the remainder are done individually. As many of the Honors section class members are ultimately interested in health careers, Duch says, "many of the experiments and problems are related to the body in one way or another." For example, the traditional center of gravity problem that may have appeared in a textbook was replaced by the students actually estimating their own centers of gravity with a book bag, placed either on or off their shoulders. Students could then understand how the center of gravity would shift in a person who had lost an arm or a leg. Duch also approaches the topic of acceleration in a novel way. Participants were assembled on the Mall and each timed a 20-meter run, while running at constant velocity versus accelerating from a stand- still position. The class also rode the elevators in Christiana East, a high-rise residence hall, to observe and record changes in their weight as the elevator accelerated upward and downward. And, students visited the UD's Sports Science Laboratory, where they saw an EKG performed. With this experiment, students gained a clearer understanding of the electrophysiology of the heart. The laboratory and classroom are no longer the only homes for physics experiments, as students also worked on a heat problem derived from the popular movie, The Wizard of Oz. The scene in which Dorothy douses the Wicked Witch with water as the latter cries, "I'm melting, I'm melting," is easily remembered. What is not so readily recognized is that, although the witch says she is melting, one sees steam. Duch poses this question to the class: "Is the witch subliming, vaporizing or really melting?" After students decided she was indeed melting, they then attempted to determine her latent heat of fusion. To solve this problem, they estimated the amount of water in a bucket and they then determined how much energy the water had given the Wicked Witch to melt her. The latent heat of fusion was eventually calculated to be so low that the witch could not have been human; that is, she was composed of some material other than flesh. Duch also aims to connect all of the concepts. "I want to help students see how it all fits together. Experts know this, but novice students don't." The project that effectively linked equations of motion and energy with those of friction and momentum was the automobile accident. An actual police accident report provided the problem solvers with sketches of an accident scene prior to and after impact. The diagram included the weight, initial direction and paths of the cars and the skid marks of one car after the accident. With this information, it was up to each group to determine if one of the cars was speeding or if the other had run a stop sign. All six groups came to the conclusion that, indeed, one of the drivers had run a stop sign. Duch says she does not take a structured laboratory approach in the class. "There are no set patterns," she says, "and students must look at problems from different perspectives." She also discusses the idea of the abstract and the concrete. "It is easiest to apply something you've seen and already understand to the abstract." One of Duch's responsibilities at CTE is working with other faculty who are incorporating some aspects of problem-based learning in their courses. In the last 18 months, over 80 faculty have attended several problem-based learning workshops sponsored by CTE. Seven faculty who use these "real world" problems and group approaches to teach physics, chemistry, biochemistry and biology have received a $240,000 grant from the National Science Foundation to introduce or continue problem-based learning in their large, introductory-level classes. -Jennifer Jones, Delaware '94