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Re: Costs of textbooks



Unfortunately the evidence from PER is that neither idea works very well.
When I went to school the lecture system was defined as: "The system where
the information flows from the notebook of the professor to the notebook of
the student without going through either mind." While there may be students
for which this is not true, they are probably in the minority. It is only
many years later that I learned how to think about what was being said and
then to take organized notes which did not contain things that I already
knew. This worked very well in a fact based history course.

One of the problems with physics lectures is that the lecturer may be
presenting concepts that the students either do not accept or are not
prepared to understand, or where the lecturer and the student do not have
the same shared context. The resulting notes will usually not contain
enough information, be unintelligible, or even say something completely the
opposite of what the lecturer intended. This problem could be completely
avoided by simply making copies of the notes and handing them out. The
lecture could then be devoted to much more productive uses.

Eric Mazur's book "Peer Instruction" thoroughly covers this problem and his
solution to it. Essentially he uses a group questioning technique which
greatly improves students understanding of the physics concepts. The ILDs
"Interactive Lecture Demonstrations" from Vernier by Thornton&Sokoloff can
be substituted for some lectures, and they also result in much improved
understanding. If you use their rules, you can develop your own ILDs and
might have much greater success. ILDs are actually popular with the
students.

There are some very good reasons beyond the ones cited above that lectures
are generally fairly ineffective. Many students have to invest a bit of
thought in writing. As a result they miss things that are being said or
done during the act of writing. Unfortunately most college teachers are
woefully ignorant of the psychology of learning, teaching, and perception,
and learning problems.

There are a number of students who are very bright who suffer from extreme
forms of the previously mentioned problem. You can divide things that you
do into 2 general classes, automatic and cognitive. Automatic tasks are
things you can do without thinking about them, but cognitive tasks require
almost your whole attention. An automatic task may be something like
chewing gum, walking, or driving your car on a familiar road. You can
perform an automatic task and a cognitive task simultaneously, but you can
not perform 2 cognitive tasks at once. For example you can converse and
drive. Of course when an emergency happens, you will find that driving may
become a cognitive task. For some students listening is a cognitive task.
When they listen their whole brain is required to hear, and they do not make
sense of what they are hearing until a few seconds later. This is rare, but
I have encountered some of these. This sort of student may be unable to
take notes. A boy I know has this problem, and he has learned how to take
notes. At the end of the lecture he has a set of notes, but he can not tell
you a single thing that has happened during the lecture. These sorts of
problem occur in varying degrees, and I suspect the cognitive load of
hearing, perceiving, analyzing, and recording is simply too much for the
overwhelming majority of students. If some of these tasks could be removed
or reduced you might get better results. A good video on learning problems
is "How Difficult can this Be?".

A large example of a problem with lectures is in teaching NTN 3 law.
Students simply do not believe what it says. The works action and reaction
conjure up motion and not forces. They know that in a collision a Toyota
Corolla is creamed when hit by and 18 wheeler so they simply do not believe
it. They will dutifully write it down, and file it under NTN3, but when
asked about a situation involving NTN3 they resort to their intuition.
However the NTN3 ILD works very well. The ILDs make the students think
about what they already "know" and they compare with neighbors, and predict
what they will see. They see an experiment where the force probes show that
the forces are equal, and they are forced to confront that they were wrong.
Finally the instructor does some bridging to help students generalize the
results to other situations. This cycle in addition to following the
McDermott predict, confront, resolve cycle also separates writing from
listening from thinking. It works at many levels when lectures and
conventional demos do not. Writing is minimized because most information is
provided in printed form and the students just have to fill in the graphs,
predictions, and results. They end up with a useful sheet to study from,
and come away from the lecture itself with much greater understanding.

The same result can be achieved by Real Time Physics Labs, or by the anchor
and bridging analogies of John J. Clement (no relation) in "Preconceptions
in Mechanics". Rich context problem solving may also have some
effectiveness, but none of these methods are not lecture methods. The only
type of text that seems to show some promise in promoting conceptual
understanding is refutational text, but students do not seem to like this
style of writing. I suspect that refutational text might be more effective
if combined with a historical point of view.

John M. Clement
Houston, TX



I've heard of another reason for taking notes: even if one
doesn't read them
later, the info. will more likely be remembered, because of the
act of writing
(in addition to hearing) -- is this true?

bc



kowalskil wrote:

Consider the following approach (for an introductory
physics course, or for another course for which numerous
textbooks are available. A teacher tells students
something like this:

"Our course has no particular textbook. I will be using
many textbooks and you are expected to take good notes.
Use any textbook you can find to help you but count on
the notes taken. ..."

That was essentially the situation when I was a student.
We knew that missing classes was highly undesirable and
we learned by taking notes. Taking notes is not a purely
mechanical process of recording; one must constantly
think and decide what is worth writing down. In most
cases taking notes is a process of active participation.
The Internet can then be used to post homework problems
and to discuss the material. What is wrong with this?
Ludwik Kowalski

Joe Heafner wrote:

From: Laurent Hodges <lhodges@IASTATE.EDU>

The cost of textbooks is worrisome to me. We had a lecturer
plan to use
one of the major textbooks, in the multi-paperback version,
and the cost
was quoted as nearly $200 (for students). I stepped in and
contacted the
rep, saying we wouldn't adopt it at that price. They
eventually gave us a
special deal, dropping the price by 1/3 - still expensive.