What I’m Saying at AAAS

Posted by Chad Orzel on February 19, 2011
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Since I had to have the slides for my AAAS talk ready well in advance, I might as well let you look at them more or less as I give the talk. So, courtesy of SlideShare, here’s the presentation I’ll be giving right around the time this is scheduled to post:

What Physics Knowledge Is Assessed in TIMSS Advanced 2008?
View more presentations from Chad Orzel.

the question I was asked to talk about is whether the released questions from the Trends in International Mathematics and Science Survey test from 2008 do a reasonable job of covering what we want physics students to know coming in. The answer: yeah, more or less. There are some odd omissions, though, and a few interesting tidbits from the scores that were released as well.

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  1. #1 CCPhysicist
    February 19, 2011

    Am I to understand that you do all of Matter and Interactions in just two 11-week semesters?

  2. #2 Chad Orzel
    February 20, 2011

    Am I to understand that you do all of Matter and Interactions in just two 11-week semesters?

    The slides do give that impression, but no, we don’t. I was just putting that up as an example of an intro physics curriculum, which would do the whole book over two standard-length semesters (13-15 weeks).

    We skip a few chapters here and there– 8, 12, 13, 24, 25. But we do go through it awfully fast.

  3. #3 Juice
    February 20, 2011

    Some processes are irreversible? How about practically all real processes.

  4. #4 Andy
    February 22, 2011

    “practically all real processes”?

    How about combustion in a non-trivial case? Light a piece of paper on fire. For extra points, reconstruct the data written on the paper.

  5. #5 CCPhysicist
    February 24, 2011

    A more reflective comment, having looked at the questions in some detail (using the slideshare version):

    What you view as an overemphasis on “nuclear physics” (basic atomic physics, isotopes, and radioactive decay) could be straight off of an exam in a very low level gen ed class that we teach out of a book (Conceptual Physical Science: Explorations) that is suitable for a one-year course in 9th grade. To me, that makes it mainstream material even if it is unrelated to a “majors” physics class. These are topics that are covered in the “majors” chemistry class your students probably take.

    In contrast, the energy problem you sampled is at the level of an actual physics class. I don’t view that as “information dense”, by the way, because there was no irrelevant information given in the problem.

    The absence of electric and magnetic fields is not surprising. Vectors are messy, especially when cross products must be evaluated to apply Biot-Savart, for example. They probably don’t do any “interesting” torque problems either. Circuits are easier to teach, easier to do with an active-learning hands-on approach, and clearly visible and real for daily life.

  6. #6 Chad Orzel
    February 24, 2011

    What you view as an overemphasis on “nuclear physics” (basic atomic physics, isotopes, and radioactive decay) could be straight off of an exam in a very low level gen ed class that we teach out of a book (Conceptual Physical Science: Explorations) that is suitable for a one-year course in 9th grade. To me, that makes it mainstream material even if it is unrelated to a “majors” physics class. These are topics that are covered in the “majors” chemistry class your students probably take.

    True, but having 25%+ of the content area be questions about notation (which is really all that two of those are) seems like a wasted opportunity given the huge amount of stuff encompassed by “atomic and nuclear” physics.

    In contrast, the energy problem you sampled is at the level of an actual physics class. I don’t view that as “information dense”, by the way, because there was no irrelevant information given in the problem.

    “Information dense” was my attempt at a compact way of saying that there’s a good deal going on in that question. I think it would be good to have some simpler questions to home in on sub-parts of the topic of energy– you know, some “The speed of a particle is doubled, what happens to its kinetic energy?” or the like.

    The absence of electric and magnetic fields is not surprising. Vectors are messy, especially when cross products must be evaluated to apply Biot-Savart, for example.

    True, but you don’t need to get that fancy. You can easily write good questions just using the magnitude of the field from a long straight wire, for example.

    There are two disclaimers that really ought to be included with this analysis: 1) These are my own opinions only, and 2) These are based on only the subset of questions that were released. It’s possible that they had more and better questions in the full test, but chose to hold them back for one reason or another.

  7. #7 CCPhysicist
    February 25, 2011

    Fair points, but

    1) the “vast amount of stuff” heads off into mini-PhD memorization territory while the limited topics they emphasized are in the category of “what everyone should know” (i.e. learn and remember) with positive pay-back in classes like our intro chem class.

    3) knowing the r-dependence of B from a wire heads away from concepts and deep into equation grabbing territory. Conceptual questions about circuits, like your doubling v question about KE (also in the “everyone should know” category), seem superior to me.

    Circuit questions, like the conceptual one you included in the talk, are perfect for inquiry-driven learning. Any HS physics class ought to be able to test the answer to that one by building it rather than going to the back of the book to see if the answer is right. That pushes the process of science and critical thinking more than E and B fields would.

    Inverse square for E or gravity, however, would be good topics for conceptual questions. Personally, I’d like one about gravity that asks for the force of gravity on an astronaut in an orbit R above the earth … with zero as one of the choices.