Midterm One

electrodynamics midterm preparationWell, it is that time again. The first midterm exam for my electrodynamics course is scheduled for Thursday and I have to decide today what to put on it.

A key factor is that it is an open book exam. Last week I explained to the class (I have another excellent group this year) that an open book exam is in fact more challenging than a closed book one, since some of them seemed to be under the opposite impression.

The point is that since we all know that if they have the textbook and their class notes and so can look things up, I certainly can’t ask them anything that they can lift from those sources without thinking. Therefore I will be able to focus on testing their ability to think and apply the techniques that they have been (I hope) studying. This is, after all, the point of the exercise, isn’t it? More so than remembering equations, in any case. (Although one hopes that all physics students can remember Maxwell’s equations…)

The drawback to all of this is that I myself have to think harder in preparing the exam. I have to construct a challenging (in a positive sense) and fair exam. I can’t do this by just grabbing stuff wholesale from the book or my lecture notes and examples. So I have to start from scratch.

This can be fun, but is dangerous. I end up, if I am not careful, writing an interesting exam, by which I mean an exam where they approach a perhaps totally unfamiliar example and uncover and learn some new phenomenon or technique as the exam question unfolds. The idea is to trust that the techniques you know are up to the job and not to panic because the situation is a bit new. (Yesterday, as preparation for my style of exam, we went through my 2007 question that unpacks the Dirac monopole, seeing – I hope – that it was quite an easy question in the end…) I love exams like that, going all the way back to my own days as a student. Unfortunately, students are seldom excited about interesting material on an exam. I don’t know why.


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12 Responses to Midterm One

  1. Jude says:

    This is the way exams should be–applying knowledge instead of requiring the regurgitation of facts–and learning something new along the way. Back when I taught Colorado history, I gave open-book short answer questions which required additional research to answer. In other words, this way of writing tests is better for every subject.

  2. Laura says:

    Ditto. Gone are the days of creative exams which I enjoyed so much as a student. The difference relies in the fact the we are here, i.e. pursuing the eternal-student career, and they are on the other side of the fence :). And look at the bright side of life: you, at least, don’t have to grade them :). I do.

  3. Clifford says:

    Actually, I often grade my exams, at this level. It depends a lot on how straightforward the exam is in terms of grading pitfalls.



  4. CoffeeCupContrails says:

    Side Note: WOW! That is one great photo!!! Dont know why, I just LOVE the cup of tea and the little notebook there. Sepia or B/W version would look even better. phew….

  5. Blake Stacey says:

    Most of the exams I had to take were open-notes, at least when we got into the “meaty” physics classes (after freshman year). Usually, we were allowed a certain number of pages, which we could fill in any fashion we desired. A few professors gave us formula sheets instead; Barton Zwiebach’s were basically highly-compressed textbooks in themselves.

    The only open-book exam I can remember offhand was the final for Introductory Real Analysis, a.k.a. Deltas and Epsilons 101. Naturally, that was the day I left my book at home, about two kilometres away, and didn’t remember it until about ten minutes before the exam started. Oh, and since this was Boston in December, that was two kilometres of ice.

    Fun times!

  6. I also have to say that I love the picture in this post!

    It also brings back good memories, as my Griffiths E&M class was one of my best classes ever. I went from being relatively lost in the early part of the semester to TOTALLY GETTING IT by the final. Getting an A on that final was a very satisfying experience.

    The page sitting right underneath your copy of Griffiths in the photo looks suspiciously like a problem from Jackson (one that could easily be made into an undergrad problem… hmm…) Which of course reminds me that I have a Jackson exam that I should be studying for. It’s open notes, which is certainly worrying, as you mention. Here’s hoping it’s not too interesting.

  7. Clifford says:

    Ha Ha! Busted! That is indeed a Jackson problem that I adapted….. it is a cool way to throw in (with guidance) a nice application of Bessel functions.

    Thanks (both of you) for the nice comments about the picture. I am glad you liked it. I just decided on the spur of the moment to snap it to spruce up the atmosphere of the post a bit. Glad it worked.



  8. Elliot says:

    Maybe after the exam is taken graded and in the books you can share one or more of the more interesting problems here and why you selected it. I think it would give people an idea of the thought process that goes into creating an exam at the college level. This is not something many people ever get a chance to see.


  9. Yvette says:

    Why is it after reading your post all I can think of is “huh, he must write some of those exams students always bitch about afterwards”? 😉

  10. Clifford says:

    All around, I’m just a bad, bad professor. 😉


  11. Jeremy says:

    I’ve always liked taking these kinds of exams more than standard ones. Aside from the fact that I can never get all the minus signs and is and everything in the right place under pressure, I always found the questions that made me think more much more enjoyable.

    However, it’s very difficult to gauge how well students will grasp the details of the “interesting” problems. I often found that my classmates would lack sufficient context to tell what the important parts of the problem were. They just wouldn’t know what to do with it other than to start writing down random problems, and hope something good happens. Though guiding the undergrads through in baby-steps seems to help resolve these kinds of problems, it doesn’t always work.

    In fact, I much prefer take-home tests to in-class tests for these reasons. I’m here to learn physics, I want interesting problems! Unfortunately, even now, in grad school, I seem to be one of the only people who thinks that. (On the other hand, I don’t want to get a lazy professor who gives a problem where I spend 10 hours calculating commutation relations or matching boundary conditions for some 5th order approximation :D)

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