Aha! An Experiment at Last!

[From Fred Nickols (2003.05.06.1235 EDT)] --

Bruce Gregory (2003.0506.1139)]

Marc Abrams (2003.05.05.0943)

By trying to make things "easier" (i.e. "talk" in normative ways) you
are having the exact _opposite_ of intended effect. People need to know
_UP FRONT_ that PCT/HPCT is _NOT_ like anything else they have ever
experienced or known. Pieces or parts of it might "seem" familiar but
that is an illusion. The sum is greater then the parts. "knowing" any
one or more parts of the model does _NOT_ help you understand the entire
process. the important thing to understand is how _all_ the parts work
together. Continuously and all at the same time. they need to "know"
that this will take time to understand. It does not come from one
reading or one visualization of a demo or tracking experiment. How many
of you in first "seeing" the tracking experiment, or the rubber band
experiment actually "understood" what you were perceiving. I sure didn't.

In my experience this applies to teaching physics as well. By analogy, it
might be interesting to create a self-test that allows the taker to assess how
well he or she understands the implications of the PCT model. Bill did this
once. Perhaps it could form the basis of a more extensive diagnostic tool. the
most useful approach that I have found asks the "student" to make a
prediction:

A number of ice cubes are floating in a glass half full of water. As the ice
cubes melt, the level of water in the glass will:

1) increase
2) decrease
3) remain the same
4) I haven't a clue

Well, at first I thought that the water level would remain the same. Then,
because I had no satisfactory answer as to why, I decided I wasn't
sure. So, I decided to find out. I put six ice cubes in a measuring cup
and filled the cup to the 8 ounce line. I then set it outside for the ice
cubes to melt while I went and took a shower. That was at 11:50 am. At
12:30 pm (40 minutes later), the ice cubes had all melted and the water
level was still at 8 ounces. While showering, it occurred to me that when
I fill an ice cube tray to one level with water that, after the water has
frozen, the ice cubes are at a level higher than the water level unfrozen;
ice cubes appear to "swell up." So, I thought that maybe the water level
would rise.

Anyway, based on the instruments and conditions at hand, as well as the
limited experimental prowess of the experimenter (and discounting any
effects of evaporation), the answer appears to be 3). However, I still
don't know why. I guess that makes the honest answer 4): I haven't a clue.

Regards,

Fred Nickols
nickols@safe-t.net