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
     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
     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
                                         -Jennifer Jones, Delaware '94