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Debora M. Katz
If you teach physics to non-physics majors for a long enough time, you are bound to be asked, "Why do I need to know this?" This question may seem hostile, and so we appeal to the student’s most selfish interest and answer, "Because it is on the test," or "Because you need to it know it for the next required class." Perhaps the student’s question is born out of a genuine curiosity. It seems likely that students may want to know how the physics that they learn in our classroom fits into their experience of the world. In fact, being able to answer that question may be the single most important thing you do for your students. Many students cannot learn physics without knowing why they are required to do so.
For the moment, imagine that you are a student who hopes to become a medical doctor, an electrical engineer, or a United States senator. You are in a physics class either in high school or college, and you have just spent three hours in a laboratory measuring the kinematics of a cart. A bright, curious student is likely to wonder why such a laboratory is important. Think of the sort of answers that might satisfy you.
I think you would be more satisfied with one of these answers than with just knowing that you will be tested on the laboratory.
These are terrific answers, but what is the best way to persuade your students that these claims are true? You have probably seen the ancient Chinese proverb:
I hear and I forget
I see and I remember
I do and I understand
The proverb tells us that when our students listen to a lecture or watch us demonstrate a concept, they don’t learn as much as when they are actively engaged. You probably use some active learning techniques in your classroom, in the hope that your students will better understand important concepts such as Newton’s laws or Maxwell’s equations. But while a laboratory measuring the kinematics of a cart is likely to deepen students’ understanding of motion, such experiences do not answer your students’ most fundamental question of why they should learn these physics concepts in the first place.
Just as lecturing is not an effective way to teach physics concepts, it is not an effective way to address this fundamental question either. Case studies are active learning projects that address not only particular physics concepts, but also the importance of physics. In general a case study has two parts: a motivating or exciting setup and a challenge to be solved by the students. A student working on a case study is like Sherlock Holmes solving a mystery. The student sees the importance of the challenge and is excited to find the solution.
A case study may be used to draw a connection between the concepts learned in the classroom and challenges faced in the outside world. For example, suppose a trucking company is being sued because one of its drivers collided with a car. Based on data taken at the scene and reported in a newspaper article, students can determine whether the truck driver was exceeding the speed limit. The motivation is making sure that justice is done. The challenge is for students to find the driver’s speed. Such a case study shows students that the basic (and sometimes boring) concepts they learn in our laboratories make a difference in people’s lives. (Will the trucking company lose the suit?)
A case study may also be used to show the importance and the process of scientific discovery. For example, a case may include an imaginary dialogue between historic figures such as Galileo and Aristotle. Aristotle would argue that a force is required to keep an object in motion. Galileo would disagree; he would argue that a net force will cause the object to accelerate. The debate is exciting. Students are challenged to evaluate each figure’s argument. Working through the same struggle that took people more than a millennium to sort out helps students to see the important place of science in human understanding.
This particular case study works nicely as an introduction to a kinematics (or dynamics) laboratory. In order to understand the difference between Aristotle’s and Galileo’s theories, students learn to take friction into account as a source of error. Then they are better able to distinguish between laboratory errors and human mistakes.
There is another benefit to using a case study that involves fictional dialogue; it allows students to address their own preconceptions. It is possible to include many common preconceptions in a fictional dialogue. When students work through such a case study, they learn how their preconceptions are connected to their formal study of physics. This process of connecting their preconceptions to physics concepts helps to break down the notion that there is one sort of physics used in the classroom, and another sort of physics used in the more complicated outside world.
My students wrote some of the best case studies I have seen. Whenever I teach non-physics majors, I always include a term project in which students ask and answer a question using the physics covered on our syllabus. Students are willing to tackle complicated and interesting problems when they choose the problem for themselves. The problems they choose to solve are generally more involved than any homework problem, and there is no doubt that in solving them, students see the importance of physics in their lives. Here are some examples:
Debora Katz has been teaching physics at the United States Naval Academy since 1995. She is currently working on a case-based textbook for university physics.