[Phys-L] Re: First Day Activities or Demos

[jsd at AV8N.COM (John Denker)]

jbellina wrote:

> Before we talk about content, I'd like to suggest the process ....

Yes, that's a good thing to talk about.

> I don't like the faith in physics examples because it begins a pattern
> of the teacher knows and students have to find out, rather than we all
> work together to make sense of our experience.  The former is a teacher
> centered activity, and latter is a student centered activity.

Yes, respected teachers have been advocating that sort of
approach for 2400+ years.  We all agree that you can't pour
knowledge into a kid the way you pour coffee into a cup.

As a rule, kids *like* to figure stuff out.

That all sounds great, like motherhood and apple pie and
patriotism ... but there can also be too much of a good thing.

The hard cold fact is that I know stuff the customers are not
*ever* going to figure out ... so I might as well tell them.

Let's be clear:  Both extremes are bad.  Coffee-pouring is bad,
and the blind leading the blind is bad.  Wisdom and practicality
lie in the middle.

Yes, teaching should be very largely student-centric.  You shouldn't
do the demo because *you* like it;  you do it because the customers
like it and learn from it.  OTOH you don't sit around like a potted
plant waiting for some student to suggest tying a bowling ball
to the ceiling.  The teacher must literally start the ball rolling
(or in this case, swinging).

The process may be student-oriented and student-centric, but it
is still teacher-led.

I've read some of the standard references on "inquiry" and they
give me the heebie-jeebies, because they grossly understate the
amount of guidance that the teacher must provide in order to
make "inquiry" work.  Sometimes the guiding hand is obvious;
sometimes it is more subtle ... but you cannot do without it,
especially early in the year.

(Of course it is a moving target;  the sort of guidance required
for students starting HS physics class is different from the sort
of guidance required for students finishing their PhD research.)

==========

Now for some more tactical remarks: I really like the swinging ball
demo, because it works on a number of levels:
  -- Physics is about making predictions.
  -- In particular, physics allows you to predict things that
   might have been a bit hard to predict otherwise.
  -- Conservation laws are a big part of physics.
  -- In particular, energy is conserved.
  -- Energy is primary and fundamental.  You don't need to know
   anything about work or force or acceleration or vectors to
   know what energy is, and to know that it is conserved.