Re: Derivations

["Roger Freedman" <airboy@sbphy.physics.ucsb.edu>]

I used to do derivations in lecture, but I gave up the practice several years 
ago.

In an introductory course such as the one you teach, the emphasis (I feel) 
should be on learning to use physics to solve qualitative and quantitative 
problems. In the limited time I have available for lecture, I do demonstrations 
and discuss the ideas that the students are expected to have read before coming 
to class. I then have the students do active-learning exercises taken from Alan 
Van Heuvelen's ALPS kit and the workbook that accompanies Randy Knight's 
textbook. The students quickly catch on that they won't have a clue about how to
do these unless they've read the book beforehand, and so read it they do! (It 
may help a little that I co-authored the textbook.)

I don't have students do derivations on exams. It seems irrelevant for the 
majority of my students, who are not physics majors (mostly engineers). But I 
think I'm doing a pretty good job of teaching them problem-solving.

As an aside, I also teach a very small (fewer than 15 students) honors intro 
course for very well-prepared and highly motivated physics majors, and in this 
course I do indeed do derivations. The differences is that in that small class I
know I'm training physicists, while in the large lecture class alluded to above 
I generally am not.

I have also taught the courses for nonmajors and for bio majors, and I don't do 
derivations there, either.

Cheers,
Roger Freedman

Mariam Dittmann writes:

> For 1st year physics, do you perform derivations for your students when 
> you teach the lecture class?  If you do, what do you hope and/or really 
> think they will get from this performance?  Also (if you do), do you require 
> your students to reproduce these derivations at a later time?  In what 
> form do you require this (on a test, in homework, in a written journal, 
> during recitations, etc.)?     If you do not perform derivations, why not?  
> How do you present the material for the course without deriving 
> formulas?  Do you expect them to learn the derivations from the book?  If 
> so, are they responsible for those derviations (i.e. required to 
> reproduce them in some form)?     In either case, how effective do you think 
> you are being with respect to the teaching of A) physics and engineering 
> majors, B) other science majors, and C) non majors.

+++++++++++++++++++++++++++++++++++++++++++++++++++++++

Roger A. Freedman
Department of Physics and College of Creative Studies
University of California, Santa Barbara

Mailing address:
Department of Physics
UCSB
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