The following is a rough draft of an essay I have been kicking around in my head, because of my extreme dissatisfaction with the instructional physics labs at uchicago. I want to say more, but it already seems longer than necessary and pretty repetitive. I honestly don’t think it’s going to go over too well with the people to whom I send it, so I would like to make the case as airtight and the presentation as brief as possible. This is probably one of those posts you want to skip unless you took a lot of physics at uchicago or are unhealthily curious about what I think about any topic. If you have any suggestions, please let me know.
As far as I am able to tell, the two appeals of experimental physics are building things and stumbling on unexpected results. I never built anything during the instructional labs, and I tried to ignore as many unexpected results as possible, since I knew that there was not enough time to explain them sufficiently and that any time I spent investigating them would only reduce the time I could spend on data taking and writing the report.
I think the instructional labs at the University of Chicago are seriously broken and that thought needs to be given to the goals of having an instructional lab program and the best way to achieve those goals.
Clearly, the practices of experimental physics differ among different sub-fields. The activities and techniques of a low-temperature solid-state experimenter are far from those of low-background particle physics, which are both different from those of high-energy physics. However, the instructional labs are remarkably similar to each other, even when the labs are associated with very different subjects. Usually, the students get the apparatus ready to take data, under the guidance of Mark, Van or a TA. This almost always nothing more than connecting wires, switching on components, or placing objects in a configuration prescribed in the lab manual. There is some discussion of the theory behind the experiment and the expected results. Then the students are left more or less alone to take the data. Taking the data usually consists of manipulating the knobs, switches, buttons of a piece of electronic equipment. This is less true of the earlier labs, where the equipment is more mechanical, and much less data is taken. Once all the appropriate data is taken, the students store it away to be analyzed. The analysis takes place using techniques that are only possible with specialized software on a computer. After or during the analysis, the student is expected to write about the theory, process, analysis, and results of the experiment, and it is solely on the basis of this analysis that the lab grade is assigned.
The point of the proceeding description of the instruction labs is that they are very similar to each other. No reference was made to a specific course, only to the fact that labs are usually more mechanical and “hands-on” earlier in the program. Despite this similarity, my suggestions of changes to the lab program were usually criticized since they would reduce the number of experiments that each student was expected to do to complete the lab portion of a course. I presume that this criticism is related to an idea of “broad exposure” to the different areas of physics that the instructors would like each student to have before graduating. However, for the reasons I have given above. I don’t think that the instructional labs as they now stand impart this kind of broad exposure, since they do not expose the student to the aspects of different areas of experimental physics that really are substantively different. The aspect that I am referring to, which is totally missing in the instructional labs, is experimental design and construction. This is what separates the sub-fields of physics from each other. In order to understand something about the differences between these sub-fields, and perhaps even something about experimental physics as a whole, it is crucially necessary to be involved in the minutiae of experimental design and construction. This involvement requires a great deal of time, and drastically reduces the number of experiments a student is able to “perform” during the program. I propose that each student be required to do no more than four experiments during his or her entire study in the physics program, preferably under the guidance of and as part of the research program of a professor. It is not a coincidence that this one experiment per year of the average undergraduate tenure at the university. I think that being deeply involved in a single, real, modern, experiment over the course of a year is the most appropriate way to learn about the practice of doing them. This gives enough time to spend on the design, construction, data collection, analysis, and conclusions of an experiment.
One might be tempted to make the following analogy: the lab courses as they are now are like reading a different book every two weeks, whereas my proposal is like spending a year on in-depth study of one book. This appears to cast the question in terms of depth vs. breadth of understanding. However, the analogy is not appropriate. The labs as they now stand are not complete books, they are partial ones, where the student starts close to the end. A better characterization of the labs as they are now would be that they are like reading the Cliff Notes and the final few chapters of a book every few weeks.
I hope that the reader is convinced of the futility of attempting to give the instructional labs “breadth” by removing the crucial, time-consuming parts of experimentation. The question now becomes how to expose students to the real way experiments are done, and the answer is obvious. Students should spend as much time as possible engaged in real experiments - helping determine what questions are most important, what kind of apparatus will best help th e experimenter answer these questions, how data should be collected, and how it should be analyzed. In order learn about what experimental physicists do, students need to do exactly what physicists do, and there is not better way than under the close supervision of a physicist. If the goals of the instructional labs, as they have been explained to me by Van, are to be met, there should be no instructional labs separate from a real, working physics lab.
Every student should be required to complete a number of hours as an intern in a physics lab equal to the time now spent on instruction labs. A grade can be assigned by the head of the lab for the year, or for each quarter if desired.
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