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What physics can do for biologists (2013)

Page history last edited by Joe Redish 3 years ago

Class content I  > Introduction to the class

1.1.4

 

As biologists and pre-health care majors, you might find it strange that you've been asked to take a physics course. What good can learning physics do a biologist or doctor? Why bother? As you have read in the prerequisite pages, biological processes emerge from the basic principles that physicists study and describe, and so you cannot understand biology without understanding physical principles. in addition, the skills that physicists emphasize are also critically important in biology and medicine.

 

Despite the fact that physics and biology -- at least at the introductory level -- tended to approach the world in different ways, the skills and competencies you develop in both sets of classes will be important to you at the professional level and even in your upper-division classes. Here are some of the skills we will focus on in our physics class that should be useful for you.

 

  1. Problem solving -- modeling and mechanistic reasoning:
    Whatever field of science you go into (and in many non-science-based professions as well), most of your actual work will not be simply recalling something you have learned and carrying out an automatic procedure. Any of those sorts of jobs are increasingly being done by machines. People are needed to figure out things that are not trivially obvious. Looking at a situation that is different from one you might have seen before, finding the similarities and differences, figuring out the knowledge and tools you need to resolve it, that's problem solving. A lot of what you will learn in this class will be through problem solving. Not just learning something and giving it back, but learning something and figuring out how to use it in non-obvious situations.

  2. Discourse -- learning to talk the talk:
    A critical idea in any science is that we use the community of scientists in a discipline to get a broader, more complete, and more accurate view of the world than any one individual can get. We're each limited in our experience and knowledge. Every scientific discipline relies heavily on the interaction of scientists with each other -- from planning and analysis discussions of research groups, to peer review of published papers, to teams of specialists in a hospital reviewing the case of a patient. In this class we will do a lot of in-class group work, both in discussion section and lecture. And your homework will include complex problems that will be too hard and time-consuming for a single individual to do easily by themselves. We hope you will find groups to work with. The point of this is not for you to "share the load" but for you to learn to "talk the talk" -- to learn to ask questions of each other until you all understand what's going on better than either of you would individually.

  3. Stakes in the ground -- reasoning from principle:
    One of the things that physics has been really good at is finding universal (or near universal) principles that hold in a very wide variety of circumstances; things like energy conservation, conservation of charge, and Newton's laws -- our framework for describing and building models of motion. These provide "stakes in the ground" for tying your safety net of linked knowledge to -- things you can trust and be sure of. But be careful! You'll be learning to do this here, but also to see that "basic principles" as applied in a real situation depend on the context and on assumptions that you might make. As a result, they can look different in different cases -- but seeing the connections and the basic principles can help you organize and make sense of a lot of complex knowledge in a coherent way.

  4. Quantification of experience -- mathematization, estimation, and scales:
    Increasingly today, biology and medicine are becoming more quantitative. Whether you are considering thermo-regulation of dinosaurs, electric forces across a cell membrane, or the interpretation of a large scale study on the value of a new drug, the researcher or doctor needs to understand the math and be able to interpret the implications of the math. Learning to use math in science (rather than just as pure math) can be quite tricky. Adding a physical interpretation to our symbols can actually change the way we think about the math. Physics is a good place to learn how to do this since you can start with situations that are close to your everyday experience. Besides learning how to use and interpret equations, in physics we often spend an effort to learn to understand different scales and to estimate quantities based on our personal knowledge. Both of these skills are valuable in biology as well.  Clearly, different scales are critical to understanding biological processes. The ability to generate good estimates can help in developing models that do not require precise quantities but do depend on "what matters most".

  5. Multiple-representation translation
    One of the things that all sciences do is to represent the complex information that they convey in a variety of forms -- words, equations, pictures, graphs, and animations. The tricky thing is to learn to create a single enriched physical picture in your mind that blends all these different representations, linking them together. You are often asked to integrate different representations in biology courses, when you study a process represented in a figure in your textbook, discuss the process in words, and apply mathematical equations to understand and predict the outcome. Physics is a great place to improve your ability to do this since it is very rich in multiple representations, even in physical situations which seem reasonably simple -- like a small bead floating in a fluid (which you will learn about in lab).  Since - unlike molecular operations - exact physical situations are often easy to visualize directly, the extra complexity of learning to interpret is not too hard to handle.

  6. Understanding measurement
    Whether you are going on to a research career, a career in the health professions, or any other scientifically oriented career, you will be relying heavily on measurement and data. Unfortunately, one of the things we learn in science is that no data is perfectly reliable.  Every experiment or measurement includes some model, both of the system being measured and of the process yielding the measurements. Understanding how measurement works -- and therefore what the measurement tells you, when it can be trusted, and when it can go astray -- is very important to a practicing scientist. Physics is a good place to get experience with this since even simple systems can involve complex issues of measurement, allowing us to focus on understanding measurement. 

 

Of course all of these skills will also be developed in your upper-division biology classes and in your post-graduate training. But physics is a great place to get started on all of these since physics digs down to underlying simple principles and universal constraints. The physics we are learning here is, in the end, rather simple. But one of the things we will show you in this class is how simple physical principles can also constrain complex living systems and offer simple constraints and a framework for thinking about biology.  We hope that in this class you will be introduced to a new, complementary way of thinking that will contribute to your understanding of the living world.

 

Joe Redish 7/11/11

Wolfgang Losert 8/27/2012

 

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