The Evolving Physics Student
October 18, 2010 1 Comment
There are several new things I want to blog about after this past weekend, and almost all of them are going to have to wait for a day or two while I finish some homework sets. However, one of them is really weighing on my mind and I thought I might be able to use this blog space as an outlet for my confusion and frustration.
My Classical Mechanics class was chewed-out a bit this morning for our collectively poor performance on our recent mid-term exam. In some respects we probably deserved it, but I think many of us felt in another sense that the test was simply unfair in some ways. It put us in a difficult position, as our professor is perhaps one of the best physicists (in the sense of being a real physicist’s physicist, more on that in another post!) at the University, or indeed, probably anywhere. So it is difficult to stand up to him and say, “your expectations are unreasonable.” At the same time, I think there really are several particular ways in which his judgement about us was unfair.
I won’t get in to the particulars of this exam and as I said, we’re hardly blameless as a class and it’s good to have high standards to shoot for, of course. But I want to talk just briefly about the more general problem that’s arising as the current generation of physics students develops a different sort of skill-set from the generation that is teaching us.
I am, for example, not nearly as good at complicated algebra as most of my professors, and I’m far less capable off finding clever ways to perform analytic integrals or simplify trigonometric expressions, too. This is in spite of the fact that, in any random group of physics students, these things tend to be one of my strengths. But the fact it, unlike the previous generation of physicists, we have an unprecedented ability to use computing power to simplify this kind of work for us. When I’m doing my homework and I encounter a complicated expression that I must simplify, I have several computer programs that can help me out, either by simplifying the expression completely if it’s just a matter of doing the grunt work, or at least by letting me test out various simplification schemes more rapidly until I find one that works.
Similarly, when I need to do a difficult integral, I am less likely to have the solution memorized because there are tables online where I can look up general formulae for them. The previous generation had integral tables too, but they were only in books, and I’m sure it made hunting for the right formula painful enough that it was often just worth memorizing them. After all, how do you alphabetize a set of integrals? And yet another example is things like the values of fundamental constants. A lot of my professors have them memorized in several units systems, whereas I tend not to have such an encyclopedic knowledge of them. That’s because I have a Wikipedic knowledge of them, and an iphone which gives me access to this knowledge any time at any place. Except in an exam room, of course.
This was one of the problems we had with the midterm exam I referenced. We were given three problems to do, and I think that, given maybe 2 hours, we each could have gotten at least a 95%. However, we were given only 50 minutes. The exam was still doable in that amount of time, but it meant there was no margin for error. A lot of us made an algebra mistake on the first problem, and had to spend 5-10 minutes finding and correcting it. That meant a lot of us barely had time to attempt problem 3.
But I’m not so much annoyed about this exam as I am conflicted about whether I am training myself badly or not when I rely so much on these kinds of technological crutches. An “old-school”* physicist would probably tell you that if you know the algebraic techniques off the top of your head, you have a deeper familiarity with them and they’re more likely to occur to you on the fly when you’re working on a problem. They would probably also argue that knowing constants lets to make “back-of-the-envelop” calculations more rapidly whenever you need to quickly estimate something. And I see a certain sense in that. But I might counter that, while I need to know enough about these techniques to be able to use them, I don’t have to understand them “deeply” in order for me to cleverly think to apply them when I’m facing a new problem. After all, it no longer involves a painful investiture of time to try out a simplification technique on a particular expression, so I’m still likely to try seemingly “unlikely” ideas. I’ll just try a few wrong ones first. And as for calculations on the fly, I already addressed that. Just because my “back of the envelope” calculation was done on the front of my iphone doesn’t change anything about the result, except that if I’m famous some day there is no valuable napkin with my equations on it to auction off.
Broadly, the discussion comes down to this: older generations of physicists probably have a deeper, more intimate acquaintanceship with the math and physics that they know and love, and thus are also able to apply them more rapidly at a moment’s notice. But us young fellows have access to a broader array of knowledge to draw from as a result of the fact that we haven’t had to memorize the details of everything we’ve already seen. And I don’t know which is better.
I’m tempted, of course, to side with my generation. Breadth always appeals to me over depth, because I am a hopeless generalist and Jack-Of-All Trades (recall that the name of this blog explicitly forbids a loss of generality). And I don’t even think I have to sacrifice depth of understanding about a subject, I just don’t keep that depth active at all times. If I need to know the full depth of a subject I’ve studied before, I may have to read an article about it to refresh my memory, whereas an older physicist might know it already. But in the end we can get the same results, and I can do it (or will eventually be able to do it) across a wider variety of fields, in general. Now, this means work gets shifted a bit from the spontaneous conversation to a thought-out exchange of ideas. Most of my professors can ask questions at talks that I would not have been able to formulate without a night’s study. But this just means that my generation of physicists will have to do less of our collaborating during the small window where we see a speaker give a presentation, and more of it by writing to them with questions about their work once we’ve had a chance to digest it. Now if only we had a new, more immediate way of communicating these questions to them. Oh that’s right, that’s what email is for!
On the other hand, I’ve always had a soft-spot for the past and tend to relate more to previous generations than my own sometimes, and I can see the appeal, and see some of the obvious downsides to the approach that people my age are (inadvertently) taking. As a matter of fact, I just used spell-check to correct my spelling of “inadvertently” (I made the last vowel an “a”) and I insisted on studying the “correct” spelling before accepting the correction so that I would not make the same mistake again. If I were going to apply the principle I advocated in the above paragraph, I shouldn’t have wasted time learning it, since I will always be able to look it up nearly instantaneously whenever I need it. But somehow that feels wrong. Ho Hum. What’s a guy to do?
I’d be curious to hear any readers’ thoughts on the matter, especially if you see it in fields outside of the hard sciences. I’m sure it must be everywhere really. It also may not matter much what the “correct” approach is, because we probably can’t convince that many young students to change their paradigm about what it means to have a competent working knowledge of their field. But even if we accept it, we’re left with some issues, including the one which kicked this whole thing off: How do professors with the old mindset test students who have a different set of beliefs about what they need to know and how well they need to know it?
Well, I’m off to lunch, and I do feel better, so thanks for letting me share. Don’t expect any more blog updates today or tomorrow (except maybe a picture or something) but do expect a few things by Thursday. I had a fun, thought-provoking weekend and I’m excited to share it with everyone.
__
*Why did I feel obliged to put that in quotes? These people are literally of an older school of thought…
WLOG blog 
I left my biology lab recitation late yesterday afternoon scowling because much of it had been devoted to berating us for doing poorly on our midterm exam. I found it galling because the duo instructors for this class are doing a particularly poor job themselves, with glaring mistakes in their self-published textbook and lecture slides and poorly worded questions.
But as to the question of what is fair and reasonable in a test, I am at a loss to say what I think is appropriate, even though I guess I should represent the “old school”. I find myself chuckling when I hear a student in lecture plaintively asking if it is expected that the student should memorize the “universal genetic code”, i.e., the table of DNA base sequences and their corresponding amino acids. It seems obvious to me that information like that is most efficiently accessed by looking it up rather than memorizing it, so it wouldn’t have even occurred to me to ask the question.
On the other hand, my biochemistry professor seems to me to have gone too far in not expecting his students to memorize the structures of the essential amino acids, arguing that that information is also so readily available that one need not have it committed to memory. In fairness, he does expect us to be able to recognize a given amino acid when presented with its structure. This came to mind just last week when, as an aside to his lecture, he endeavored to draw the structure of urea on the board. He got it perfectly correct, but I found it disconcerting that he was hesitant in being able to call to mind the structure of such a simple molecule. How could a biochemist not immediately be able to bring to visualize the structure of the first “organic” molecule ever synthesized by chemists?
The question of time constraints is also an interesting one. In lecture yesterday my genetics professor was dismayed that the class could not remember a concept she had presented to us at the beginning of the semester. One student offered the explanation that the information absorbed from that period was “flushed” following the first midterm to allow room for the next collection of facts to be absorbed. Needless to say, that did not sit well with the professor. I imagine that there is some justification to having to complete tests under time pressure as it forces additional familiarity with the material, but it does seem unfair when it is lack of facility with the mechanics that prevents a student from demonstrating understanding of the concepts.
Even though my classes are trivial in comparison to yours, I certainly empathize with your frustrations and questions!