Six Ideas Magazine (Aug 2007)


The purpose of this magazine is to provide a forum where users of Six Ideas can share their ideas and experiences about using these texts with other users. It will also be a place where I can communicate news of interest to the user community. Please consider contributing a note or article!


--- Tom Moore (editor)


A New Approach to Homework

(Tom Moore, 8/19/04, updated 8/7/07). At Pomona College, we are using new approach to grading homework that has proven to be simpler to manage and more resistant to cheating than the two-pass system described in the Instructor's Manual, while offering most of the same advantages. We have been using this system now for more than four years, and it has definitely stood the test of time.


Submitted problems are graded on a 10-point scale as to whether they were Complete (3 points), Clear (2 points), Plausible (1 point), Initially OK (1 point), and Correct (3 points). Rubrics for assigning grades were as follows:


  • Complete
    3 = all parts present and fully developed
    2 = some parts incomplete
    1 = major sections missing
    0 = little meaningful work done
  • Clear
    2 = model (i.e. physical reasoning) was clear to the grader
    1 = some aspects were unclear
    0 = model was completely opaque
  • Plausible: One point was awarded if the result's magnitude, sign, and/or units were plausible.
  • Initially OK: One point was awarded if the solution was acceptable on the first pass.
  • Correct
    3 = no modeling or algebraic errors
    2 = some modest errors were made
    1 = fundamental errors were made
    0 = almost nothing was correct

I went to a local postal services outlet and ordered a self-inking rubber stamp that read as follows:


___ / 3 Complete
___ / 2 Clear
___ / 1 Plausible
___ / 1 Initially OK
___ / 3 Correct


When students submit initial efforts, undergraduate student graders stamp each problem with the stamp and then grade each initial effort completely, marking numbers in each of the slots on the left side of the stamp. They also record the total grades for each problem on a sheet to be submitted to the instructor. The required time was roughly 2 person-minutes per submitted problem set. With only a bit of initial guidance, the graders (who were mostly sophomores) did a quite satisfactory job of marking the papers.


Once students receive their graded papers back, they were allowed to submit corrections (in green or purple ink) on Wednesdays. Students could earn additional points only for the "Clear" and "Correct" categories: the scores for all other categories remain fixed at their initial values. This implied that students could earn a maximum of 9 points on a complete and plausible but incorrect initial effort after appropriate correction. Students are allowed to submit no more than 4 problems per week, and had to submit corrections to a special mail box, but they are free to submit any previously graded problems for correction.


We have found that about 30% of the students submit an average of two or more problems a week for correction. I personally grade all the corrections (partly because I want students to know that I would personally look over their work if they disagreed with the grade they got initially), but it takes me less than 1 minute per submitted problem set (less than 1 hour a week) to go over the paper and enter the corrected grades (indeed, I find that most of the time is spent physically locating the score on the grading sheets that needed correction: a cleverer system for doing this could save a lot of time).


This approach has several advantages over the system described in the original instructor's manual. Since all problem are completely graded initially, students cannot cheat by passing off corrections as original work, and they do not have to submit corrections (which was easier on the students). The much lower number of corrections coming back greatly reduced the paper-flow and the work that the final grader needed to do. The scheme still strongly rewarded effort, and still provided incentive for students to at least look at the posted solutions (if only to decide whether to submit a correction or not). It also provided a natural way for students to appeal initial grades that they considered unfair (this helped make it possible to use undergraduate graders). All in all, we have been very pleased with how well it works.


This scheme can be adapted to larger classes than mine (indeed, Tom Bernatowicz and Becky Trousil have been using it successfully in fairly large classes at Washington University). The final pass needs to be done by someone students will trust as an authority, but a graduate student can easily fill this role, while the first pass can easily be done by undergraduates. I don't consider the exact categories or particular point values assigned to each category to be sacrosanct either: some adaptation might be appropriate for your institution.


In summary, I highly recommend this approach!


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Source Code for Programs is Now Available


(Tom Moore, 8/11/06, updated 9/11/07) The REALbasic source code for all of the programs posted on this web site is now available on the computer programs page. You can download, use, and modify this source code as per the GNU General Public License, version 2 or higher, which is included as part of each program.


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Viewing Solutions Online!

(Tom Moore, 8/20/05, updated 8/7/07) Many instructors have been asking for a way to post problem solutions so that students could view them online. We have finally developed a system to do this that we believe will be both secure and easy to use.


In this system, certified instructors can define a list of problem solutions to view, a time window during which each solution is available, and a password to access the list. Students in that instructor's class can then use the ProbViewer program (see the Computer Programs page) and the instructor-provided password to view the solutions. This viewing program is available for the Mac OS X, Linux, and Windows platforms.


Instructors can learn about how to submit lists by visiting the special instructor's page through the gateway. The current protocol for submitting lists now (as of 2007) also allows instructors to set up their own solutions (either for their own problems or improved solutions to standard problems) so that they can be viewed through ProbViewer.


Version 1.4 of ProbViewer is a required upgrade for everyone, as I have been compelled to change the directory structure on the computer that serves the solutions.


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Draft Edition of Unit E Third Edition is Available


(Tom Moore, 8/11/06, updated 8/7/07) A draft edition of the 3rd edition of Unit E is available from McGraw-Hill Custom Publishing (I also recently saw that it was available from Amazon). The ISBN is 0-07-354099-4. A discussion of what has been changed appears here. Instructors at Pomona and at Washington University have been using this edition since the spring of 2006, and we all agree that this version is a significant improvement over the 2nd edition. We therefore strongly recommend that all users consider adopting this version.


Even so, more improvements may be in store: see the story on the Mellon Workshop below.


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Review of Six Ideas Appears in American Journal of Physics


(Tom Moore, 8/11/06, updated 8/7/07) You can find full and thoughtful post-use review of Six Ideas by Tom Bernatowicz of Washington University in the March 2006 issue of American Journal of Physics. Tom has been using the text in fairly large classes at WU, so this review may be particularly helpful to those of you from large universities who are considering the text. (Note also that he wrote this before the draft 3rd edition of Unit E was available.)


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Mellon Workshop on Teaching Electricity and Magnetism


(Tom Moore 8/7/07) On June 25 and 26, 2007, selected faculty from Washington University and Amherst, Smith, Wesleyan, Williams, Oberlin, Grinnell, and Pomona Colleges gathered at Smith College to discuss how to teach introductory electricity and magnetism. The workshop was funded by the Mellon Foundation, and Nalini Easwar of Smith College and I ran workhop.


Our goals were to share ideas about how we might teach electricity and magnetism in the introductory course in exciting and effective ways, and to help develop my vision for how to better shape Unit E in the future. I found the workshop useful and inspiring, and I am very grateful to my colleagues for giving me great feedback on proposed changes and new ideas and perspectives on this material. These ideas will help shape the final 3rd edition of Unit E.


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