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Worst instructional tool of all time

  1. Jan 29, 2008 #1
    I'm a student in AP Physics C right now, and my teacher is using this program called Webassign. Absolutely horrible. All of my class and his normal physics classes hate it, but the man refuses to change to just plain old book work!

    Anyone ever used this program or similar ones? What do you think of it? Positives and Negatives?
  2. jcsd
  3. Jan 29, 2008 #2
    My major issue with WebAssign is that you can't receive partial credit. The answer is either completely right or wrong.
    You also have to be careful about rounding during intermediate steps of the problem. When I had physics courses that used webassign, you usually had to be accurate to three decimal places in the final solution or the problem would be marked incorrect.
    It certainly makes homework grading easier for the instructor though.
  4. Jan 29, 2008 #3
    At my school they also use webassign, its the only form of assesment they use, and also is the only form of homework they set, the majority of my year agrees that its pointless, as large portions of what is set for us is not relevant to our physics A-level.

    The worst problem is the fact that the teachers now no longer teach us properly and expect us to learn of webassign. I think if used properly it could probably be alot more usefull but on its own its just pointless.
  5. Jan 29, 2008 #4

    Agreed. It seems theres been too much dependence lately on technology as a teaching tool. As you said, if used correctly(as only a supplement to a good lecture, and not a teaching tool itself), then Webassign could be useful for everyone.

    I cant believe they make you use that for EVERYTHING. I only needed it for physics, but I would most likely kill myself if I was in your predicament.
  6. Jan 29, 2008 #5
    My school uses something similar, MasteringPhysics, but I have to say that I really like it.
  7. Jan 29, 2008 #6


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    Um, why are you rounding at all during intermediate steps? Doesn't your calculator have any memory registers?
  8. Jan 29, 2008 #7

    Ben Niehoff

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    The worst aspect of tools like these is that the instructor can unintentionally create impossible problems. For example, even though the final answer may need only 3 significant digits, the details of the calculation might be such that far more digits are required to reach the final answer accurately; I had numerous occasions in college where such tools required in intermediate accuracy beyond the means of a standard calculator.

    Generally, the numbers given in the problem statement are randomized (so that each student is given a slightly different problem). If the instructor is careless in coding the randomizer, nonsense can result. Case in point:

    In my freshman engineering course, we were doing a section on statics. The professor set us a problem, via the web, as follows:

    A helium balloon is tethered to the ground via three tethers, which are anchored at three points in the XY plane: (x1,y1), (x2,y2), (x3,y3). The balloon has a net buoyant force of F and is hovering in equilibrium over the point (x0,y0). (All specific numbers are randomized.) Find the tension in each of the three ropes, and the unit vectors along which each of these tensions act.

    That's all well and good, except the vast majority of students (myself included) kept coming up with negative tensions, no matter how we tried to calculate them. We brought this up with the professor, and he told us we must have done it wrong, because "You can't push a rope" (he repeated this rather dogmatically). Sure, you can't push a rope, but you can write bad code for a problem that involves unphysical rope-pushing...

    What had happened (and I had to demonstrate this with rigorous mathematics to the professor before he would back down and re-grade the problem) is that the random number generator was not taking into account the physics of the problem. All four points P1, P2, P3 and P0 were chosen independently. This meant that, the majority of the time, the point P0 was actually chosen such that it was outside the triangle formed by P1, P2, and P3. This would mean that, unless there were a wind pulling the balloon in that direction, at least one of the ropes must be in compression rather than tension in order to hold the balloon in place.

    Thus, most of the class had actually done the problem correctly. They got an absurd result because the problem was coded to give them an absurd physical situation.

    Moreover, this guy had required about 10 significant digits on the three unit vectors in Part B. I think what actually happened is that the code must have been checking for strict equality, using floating-point numbers, instead of using a small error bounds. Thus, it was often impossible to satisfy the precision required to get any points. (I remember quite often in this class that students would have to enter 10-12 digits in their answers all the time, and for no reason other than the professor was paranoid about cheating and guessing).
  9. Jan 29, 2008 #8
    Used Webassign for first year physics homework and exams. Never had any problems with it, really.
  10. Jan 29, 2008 #9


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    Once you graduate and start real work you won't get partial credit either, so get used to being completely right or completely wrong.

  11. Jan 29, 2008 #10


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    Your teacher does not actually have lessons prepared? Are you required to go to an actual class?

    WebAssign is primarily an assesment tool.

    Last edited: Jan 30, 2008
  12. Jan 29, 2008 #11
    When I was taking physics thats what he used as well is web assign, hard stuff~
  13. Jan 29, 2008 #12


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    omg, I'm so glad I'm past an education that uses such a tool. If I had to contend with this kind of thing it would drive me crazy - it would be easier to see the flaws than to do my homework. I'd probably do what Ben did, in an attempt to prove the tool is harmful.
  14. Jan 30, 2008 #13


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    I was thinking of your typical freshman-physics problem in which the input data is given to three significant figures. Students who don't know how to use a calculator properly tend to do each step separately, and round off each intermediate result to three sig figs, which usually causes a small (sometimes not so small!) error at the three-sig-fig level when they get to the end. The situation you describe is different, and I agree it's unreasonable.
  15. Jan 30, 2008 #14


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    I am a teacher and I don't want to use webassign. I give them problems and I marked them myself, giving points not only for the answer but also for their solutions. I care more about how they solve a problem than their final answer, actually. Someone may get completely the wrong numerical answer but still get most of the points because most of the steps are correct.
  16. Jan 30, 2008 #15


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    Out of curiosity...
    How many students do you have?
    How many problems per assignment? and How many assignments per week?
    Can you sense if students are really doing the problems? or just copying from someone else?
  17. Jan 30, 2008 #16


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    I think that's great for exams, but for homework, which is generally a smaller percentage of the total course grade, WebAssign works well by reducing the load on the instructor.

  18. Jan 30, 2008 #17
    That may be true, but so is the contrary - in much of the real work early physics students will be doing (mostly engineering, really), if they don't include their work and process of thought carefully, what they did has no value. Webassign continues a secondary school obsession with the final result, but the process can be as or more important to a company.

    Webassign might be an assessment tool, but it isn't a good one for physics.

    At least it gives professors and grad students more time to do research. . . but the fact that the students are paying more for this instead of less is just criminal.
  19. Jan 30, 2008 #18
    Funny enough, I'm right now using WebAssign. It's the third(!) such online homework product I've used, and they all have the same issues. Somehow I had the mistaken impression that my tuition was for something other than finding ways to fob me off on a computerized kludged-together quiz board.
  20. Jan 30, 2008 #19


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    When I was paid full time I was going crazy during the semester, working over 60 hours a week because of all the marking. So I paid a voluntary pay cut and am now working 75% of a full load, which means that I can get all my work done in a more reasonable 40 hours or so, leaving me some time to do research.

    Last semester I taught one course and had 59 students.
    I understand that in large classes, the prof can't mark everything. But I would think that then the school should have graders. I just feel that the students gain a lot by seeing their solutions corrected as opposed to having only their final result marked.

    I end up marking a couple of hours every day (seven days a week), on average. That does not include the lab reports ;-) I had to find some tricks to cut down the time to mark. A lot of time used to be spent writing the same comments over and over again. So a trick I use now is that when I see a mistake that I know wil be frequent, I start a list of comments (like A=you use the wrong angle for the tension, B=you rounded off too much, etc). When I mark I simply write the letters and post on my office door the key for the comments. That saves a huge amount of time. I still have to write something when someone makes a mistake completely different than anything else I have seen, but that's the exception.

    I give about 5 problems an assignment. One assignment a week except the weeks of tests (when I assign practice problems and make solutions available).

    Good question. It's impossible to tell, except when I see some mistakes exactly repeated. I get the impression that maybe 10 % copy directly from others. But I know they will get penalized atthe tests, which are worth more.

    The vast majority make a honest effort and they learn quite a bit from seeing the whole work corrected.
  21. Jan 30, 2008 #20
    You must not hang around the FEA guys (Well, in order to get it to mesh, I had to assume the wing was a homogeneous sphere).
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