Re: telling them lies

[palmer@sfu.ca (Leigh Palmer)]

> Subject:     Re: telling them lies
> Sent:        9/7/96 9:47 AM
> To:          phys-l@atlantis.cc.uwf.edu
>
> > I see. Tell them a lie, then tell them you lied. Why would that be good?
> > I guess you could recycle books that taught the caloric model, but I can
> > think of no other advantage.
> >
> > Piaget knew how to deal with concepts that were inately abstract. You
> > wait until the subject is sufficiently mature to absorb them [a]s such.
> >
> > Leigh
>
> I take exception to this comment in two respects, both stemming from my
> commitment to constructivism - the idea that students actively construct
> new understandings when they learn.  Firstly, the characterization that
> students "absorb" concepts is dangerous.  It implies that all we have to
> do to teach them is to tell them the right stuff.  If they are
> sufficiently mature, then they will learn it.

Commitment to a cause is admirable, and it does tell me that I won't
convert you. Notwithstanding your belief, I have successfully taught
the concept of entropy to students ready to assimilate it, and they
did not pick it up elsewhere or arrive at it by the discovery route.
Telling them first that entropy is a measure of the disorder in a
system did not make my task easier, I'm absolutely convinced, so don't
you try to convert me, either. I have a deep commitment to the idea
of empirical validation.

> Secondly, since the raw materials for a student's construction of new
> knowledge are her old knowledge and the sense she makes of the teacher's
> instruction, the advantage of teaching a caloric model of heat may be
> that it is an easier construction to make.  Then, having learned a
> conception of heat as a fluid, she can begin to construct a more fruitful
> conception including the concepts of internal energy, heating as an
> energy transfer, etc.  John Clements has published extensively on the
> idea of using such "bridging analogies" in the teaching of physics.  The
> idea is that we ask too much of students when we expect them to construct
> a fully accepted scientific conception from the type of knowledge they
> are likely to bring with them.  The leap is too large.

If insignificant time elapses between the use of that analogy and the
revelation of the Truth (well, the paradigm of the day) then no harm
is done by giving them a flawed analogy. Feynman does exactly that in
his chapter on conservation of energy to which I alluded before. He
introduces the idea of energy as toy blocks, but before he even leaves
that section of the chapter he drops the bombe that energy is exactly
like the blocks - except that there are no blocks! If you haven't read
it you owe it to yourself to do so. It is so good I don't try to do it
myself; I just read a long quote to my class as I write down his
equations. It is beautiful, and I use it on students who have been
introduced to conservation of energy previously in high school.

Leigh