Re: Old guitar strings--actually Leigh's comments

[Leigh Palmer <palmer@sfu.ca>]

> > oddiyies I meant it. *I* was unaware of the bullet business until John
> > Mallinckrodt made me question it, which I did. I now know something I
> > didn't know before, which gives John a bit of well deserved
> > satisfaction. I get my jollies out of perforating the pomposities of
> > pretentious physicists*, even if I have to burst my own balloon
> > occasionally.
> >
> > Leigh
>
> ...would it be appropriate to assume you therefore have been over-reaching
> your own competence to have taught projectile motion before your latest
> insight gained at the hands of the great M?  Clearly you did not have a
> "full" understanding of the problem; did you every teach about it thus
> unprepared?  Perhaps the great one should certify us all...
>
> Dan M (with tongue in cheek, sort of)

Since this is a discussion group I'll assume this is not a rhetorical
question. I consider the topic of whether *I* have overreached my own
competence to be interesting, and since I know the answer on several
levels, including the question of falling bullets, I'll address the
question of whether I've overreached my competence in that area directly.
It is possible that I have, though I can't recall having done so. I always
relate it to a "monkey and hunter" story and I perform the demonstration,
and it turns out always that I am correct. I also tell them that Galileo
did it for cannon balls, and it seemed to work there, too. I don't recall
ever having been asked about bullets, and I wouldn't have volunteered the
information, but as I said before, had I been asked I probably would have
agreed that bullets do fall with one gee, especially if I didn't have time
to think about it, as often happens in a classroom situation.

As to the broader question, yes I have overreached my competence in my
teaching, especially when teaching astrophysics. As I've mentioned before,
I don't really know GR, but I quote some results from it. I share my lack
of qualification with my students whenever the topic arises. It often
arises in other areas, and I do try to adhere to truth in packaging
standards when it does. For example, in my astronomy course (which is
intended for nonscience students) I talked about global warming and the
terrestrial greenhouse effect. In some of the areas I talked about I know
no more than I read in the front of Science and Nature (not the scientific
contributions) but I figured it was worth passing these on, together with
the caveat that I am not an expert, and that the experts are themselves
divided in important ways. The topic naturally arose when I was talking
about planetary atmospheres and I wound up spending about a class and a
half on it. I was overreaching my competence, but there is no one here at
SFU any more competent than I to talk about the subject.

Next time I teach projectile motion (which may be never) I will certainly
tell my students about bullets and their departure from "ideal" behavior.
What would be the value of learning something like this and not sharing
it, especially when there are important points to be made by doing so? I
will be straing my level of competence there not at all, since I will be
telling them the known limit of validity of this treatment.

Leigh