College Physics with Biomedical Applications at Cleveland State University: A Two-Year Experience
Ulrich Zurcher, Cleveland State University
The report BIO2010, by the National Research Council (NRC), offers refreshing ideas for the introductory physics sequence taken by biology majors. It suggests the inclusion of three broad themes: (1) biological systems obey the laws of physics and chemistry, (2) collective behavior of complex structures emerges from simpler units, and (3) living systems are far from equilibrium. The report makes recommendations for a course geared towards future research biologists without restrictions like those imposed by standardized exams such as the MCAT.
In this article, I will report on some of my experiences teaching a course with biomedical applications at Cleveland State University (CSU). CSU is an urban, public university in which a fairly large segment of the approximately 7,000 undergraduate students enrolled are the first in their families to attend college. In the spring 2004, I proposed a new College Physics course with biomedical applications. I have taught this course every year since then and I have found that my focus on biomedical applications creates a "storyline" that is helpful in providing connections between the various topics we cover. Our course meets twice a week for 75 minute-lectures, and once a week for a two-hour laboratory session.
Methods
In my experience, one of the greatest obstacles to teaching a course geared toward biomedical applications relates to the number of "required" topics that one might feel must be covered. This is reflected in standard textbooks, which run between 950 and 1,100 pages. I have found that two approaches are particularly helpful in navigating this difficulty.
1. Students explore new material in the lab . They do not simply "confirm" what has already been covered in the lecture. This is accomplished using a lab manual that I have written with which students are guided through the material by answering a series of questions.
2. Students are expected to read through the relevant sections of the text before coming to class. My choice of the textbook is conventional [currently J. D. Cutnell and K. W. Johnson, Physics , 7th ed. (J. Wiley and Sons, New York, 2006)]. I use Wiley-Plus for both homework and daily quizzes. The online quizzes are essentially reading assignments, and are always multiple-choice questions. These quizzes relate to the material covered the next day. The combined score of daily online and in-class quizzes accounts for 10% of the course grade. To my surprise, I receive only a few complaints about excessive workload from the students.
Content
The biological and medical fields are an ideal source for physics problems that are rich in context. For example, how fast can an animal walk or run? What is the maximum height an animal can clear during a jump? How tall can a tree grow? Such problems cannot be solved by simply following a recipe. One must first identify the important components and then construct a model. In contrast, the typical end-of-chapter problems in textbooks are often quite "formulaic" with little relevance to realistic situations. Students can often solve such problems by simply looking for patterns, identifying the relevant equation(s), and inserting the numerical values given in the problem.
In the problems cited above, students explore how various biomechanical functions [e.g. locomotion] depend on the size of the body. Such relations are referred to as allometric scaling in the scientific literature. My experience is that students find these discussions stimulating. In the first semester, I also discuss the properties of surfaces (e.g. surface tension) and how it determines the metabolic rate of animals. I have expanded my coverage of thermodynamics to include topics such as diffusion.
Another important idea for biology students is that macroscopic objects are typically electrically neutral and the weak gravitational force dominates interactions between them. Yet electrical forces are at the root of microscopic properties of materials [e.g., elasticity], and determine the form and function of molecules like proteins. Standard texts often fail to make this point. So, in the second semester, I emphasize these distinctions and focus on problems with realistic applications. I discuss, mostly quantitatively, how electricity is generated by the charge separation of ions (electrolytic solution). I also talk about how electrical signals travel along neurons. We cover various methods that can be used to "look inside the body". For example, we discuss ultrasound, MRI and X-ray imaging.
I have developed several completely new laboratories for this revised course. For example, I wrote a lab on exponential growth and decay. I introduce the notion of rates and rate equations by using interest rates and inflation. Students use Excel to calculate the growth/decay of an initial quantity, and then compare it with exponential behavior. Finally, students explore why exponential behavior is so common in many areas of science, technology, and society.
Summary
The report BIO2010 is a challenge to physics faculty who teach physics to biology and pre-medical majors. Proper course management makes it possible to incorporate discussion of context-rich problems with biomedical content. The BIO2010 report is a starting point for a broader discussion within the physics community regarding which should be the core topics in the algebra-based course sequence and which topics are optional. It also invites authors (and their publishers) to supply teachers and their students with slimmer texts that focus exclusively on these core topics.
Ulrich Zurcher is an Assistant Professor of Physics at Cleveland State University. He can be reached via e-mail at u.zurcher@csuohio.edu. |