Problem Based Learning

As suggested by Nelson in “Improving Questioning and Problem-Solving Skills” and elsewhere in the readings, problem based learning involves real world problems that are open-ended that may not have an obvious solution. Real world problems in Physics are extremely difficult for most students. Is it realistic to ask students to solve very difficult problems? If you pick up any physics book and examine the problems at the end of the chapter, you will find many problems that are constructed around some type of physical event in the world, but the problems are almost always very limited in scope, meaning one or two concepts apply to that problem. Real world problems as suggested in the readings immediately bring to my mind scenarios that are broad in scope, many different physical principles must be applied in the correct order to solve the problem. Selecting the correct physical principles and deciding how to apply them in the proper order is a daunting task even for the very best student. Most of the time the student will give up and feel crushed by the problem. Thus it is important to offer a series of problems that are relatively straight forward that allows the students to apply 1 or 2 principles at a time to build confidence. After considerable practice, only then is it possible to offer a problem that involves several principles at once, but even then most students will consider such problems to be very difficult.

Knowing the difficulties the students will encounter I set about to construct a real world problem. The first question to ask and answer is what physical principles did I want the students to use. The next step is to think carefully about how to write the problem to ensure it is limited to the selected principles and does not lead into or morph into something far more difficult than intended. In the problem I selected I limited the principles to basic projectile motion, but this “is” the real world so error analysis must be considered. Probably not realized by most people, in Physics, most of the time real world scenarios are modeled using an ideal world. For example in the ideal world there may be no friction, but in the real word friction does exists. Often it is helpful and sometimes necessary to model a simplified ideal world to better understand what is happening in the real world, precisely because the real world is very complex. The problem I designed requires the students follow the process a physicists would use, first start in the ideal world to better understand the real world problem.

My main concern is most students are not practiced at modeling an ideal world and may find the problem I have designed for them to be too difficult largely because they are unable to break it down into an ideal problem. By the time they get to the problem they will have practiced in the ideal world each principle needed to solve the problem. But will their conceptual understanding of the principles be sufficient for them to proceed through the comprehensive critical thinking process to find a solution to the problem? I believe I have limited the scope of the problem sufficiently to allow the students to solve the problem, but I really don’t know how the students will react until they try it.

The first time I will be able to assign this problem will be about two weeks into the start of the 08 fall semester. I plan to assign the problem about three weeks before it is due. At that time the students will not have covered all the topics in class needed to solve the problem. During the two weeks that follow the assignment, all necessary topics will be covered. Hopefully the students will be thinking about the problem as the relevant topics are covered in class.