Re: [Phys-l] index of refraction

["John Clement" <clement@hal-pc.org>]

> Sorry, but I really have no firmly held opinions on this. I use both types
> of approaches - especially in my courses for non-science majors. I simply
> noted some comments made by my students in the verification labs and you
> jumped on board basically telling me that the students making these
> comments ("Now I get it.") were misinformed.
>
> Next time I'll believe you versus my own lying eyes.
If your read what I wrote, you will see that I am not saying the statement
"I got it" is necessarily false.  It may or may not be, that is the
question.  How do you know they really got it?  I certainly don't know!!!  I
question whether it is evidence.  While anecdotal evidence may be personally
very convincing, it is only an indication of what may have actually
happened.  I have gotten the "now I understand" reaction from students, and
then seen them not show it on subsequent evaluations.  This has happened
often enough that I am suspicious of student praise, even while I enjoy
basking in it as much as the next person.  Medical studies often contradict
what physicians know from just observation!  Oh, and you did give the
impression that you thought verification labs were just as good as inquiry
labs, something which I am firmly convinced is not so.  And research based
courses usually get lower student evaluations even while FCI gains go up, so
student evaluations of their own learning may be suspect.

A post previous to mine seriously called into question the use of
verification labs using a "physics like" argument.  An subsequent posts also
did the same.  Now I presented some research data as part of my answer, but
nobody seems to want to refute it.  So I am perceived as more
confrontational, which I probably am!

Yes, I use anecdotes as illustrations, but generally in conjunction with
research based evidence.  I am fully aware that anecdotal evidence can be
very misleading.  The cognitive research challenges preconceived notions
just as much as physics research does.  QM was totally counterintuitive to
the classical paradigm.  I suggest that the research base for education
often comes up with counterintuitive results.

You may be getting good results, but verification labs are decidedly
inferior according to what we know from the research.  Shayer and Adey have
found that all levels of students improve in thinking when they use their
inquiry lab program.  So using verification labs is probably shortchanging
all students.  If you need further proof of the efficacy of inquiry look at
the ADAPT program at UNL.  They used inquiry labs in a remedial program and
had much better student retention and much lower rate of failure in
subsequent courses.  It was at least partially designed by physicists.  Then
of course there is work of Joe Redish who showed that a "studio style"
course made students exhibit more expert like attitudes, while conventional
courses caused attitudes to worsen.  Anyone can verify this by using his
MPEX evaluation.  Anyone can see if thinking is improving by using the
Lawson test.  We have a whole array of evaluations that can be used to see
whether a change in methods has yielded improvement.

As to "lying eyes", we have to be aware that our eyes and ears do deceive
us.  Our senses are very fallible, as is our judgment.  I have seen videos
where someone asks directions and while the patsy is giving them, a crew
with a large panel walks in between them.  A substitute questioner is left
behind, and the patsy is never aware of the switch.  The new person can even
have a different color shirt.  A video can be devised where suddenly whole
object disappear, and you can't easily detect that this has happened.
Another video has a man in gorilla suit walk through it, but if you are
following the basketballs as instructed, you don't even see it.  It is also
possible to come to the opposite conclusion from what is being presented if
your paradigm blocks the idea.  We invent patterns even when they are not
there.

It is well known that charlatans can deceive physicists, but not a team of a
physicist with a magician.  Magicians know what to focus on, but physicists
can be surprisingly credulous.  There is a wonderful NOVA where the Great
Randy exposes charlatans even when scientists can't.  Yuri Geller willingly
performed before scientists, but would not in front of Johnny Carson who was
a magician.  And yes, I can be deceived!

Please notice that each of my comments has a rational basis, and please note
what that basis consists of.  Usually I have a research based basis.  And I
gave a reference to a power point by Schwartz.  Has anyone looked at it?  I
have referenced the Michelle Perry paper a number of times.  Has anyone read
it?  Perhaps someone can find flaws in their experiments or methodology.

Incidentally Schwartz or one of his collaborators has presented at a
previous PER conference.

There is even the possibility that no labs might be better if a superior
alternate didactic sequence is found.  There is research that a video that
didactively presents a physics concept basically does not improve
understanding.  But if you add a presentation of a student discussion at the
end of the video of common misconceptions, understanding is dramatically
improved.  Notice the students on the video must be similar to the students
in the class.  However we don't know if transfer is improved or killed, and
we don't know if the gain is superior to other methods.  There is also the
question of long term retention compared to other methods.  There is
research that shows that students who interact with a simulation of circuits
are faster at wiring real circuits than students who did identical labs
using physics equipment.  I found that one quite surprising!!!  Oh, and most
of the research on textbooks that I have seen show very small gains, but
people do not want to hear that either.  But I am open to new evidence.

John M. Clement
Houston, TX