Re: [Phys-l] the role of simulation

[Hugh Haskell <hhaskell@mindspring.com>]

At 12:18  -0600 1/19/08, John Clement wrote:
> It is not an alleged fact, it is a fact that this happened with the
> experiment which was reported in the journal I already referenced.  Now if
> anyone wants to repeat the experiment they are welcome to do so.
I just read the article John refers to and I found it very 
interesting. I can think of a few things I wish they had done (or 
talked about if they did them), but in general I thought the paper 
laid out pretty convincing evidence for what they were investigating. 
It does seem to me that the issue of wire color and overly dim bulbs 
were issues that could have been dealt with early on and then would 
not have become distracting factors from the main point of the 
experiment.

My experience has been that students have a great deal of trouble 
understanding electric circuits in the beginning, even when they have 
lots of hands-on experience as well as careful supervision of their 
efforts (as long as that supervision doesn't include doing the work 
for them). I don't see how the simulation could make it any worse.

One aspect of simulation that has been hinted at but not explicitly 
dealt with in this thread is that simulations can do things that you 
simply cannot do in the real world, usually for issues of safety or 
cost or physical possibility. I have not used a flight simulator for 
many years, but I do recall that they had the capability of driving 
the pilot flying the simulator over the edge with compounding 
emergencies. While such events would be very rare in real flight and 
often simply cannot be simulated in the air, they can easily be done 
in a flight simulator, and doing this is something like a batter 
swinging a bat with a weight added before coming to the plate--if you 
can handle three or four simultaneous emergencies in the simulator, 
you are more likely to be able to handle one or two in the air. I 
recall on many occasions coming out of the simulator bathed in sweat 
and exhausted, even though I had never left the ground or felt the 
slightest additional g-force.

In the lab, you cannot repeal the laws of physics, but in the 
simulator you easily can, and the students can see the effects of 
some of the preconceptions they come to physics with, and why we no 
longer accept those ideas. To come back to what originally launched 
this thread, a simulation can show what a 1/r^3 or 1/r law of gravity 
would do. I know that IP can also simulate a short duration 
perturbation of an orbit (I think the original discussion got 
sidetracked on changes that were not what we normally consider 
"perturbations" but altered initial conditions).

Also in the lab or classroom we seldom have the time, equipment or 
ability to simulate lots of special cases of various laws, but the 
simulator can do that quickly and easily.

So, not only in the cases like that in the paper John referred us to, 
where the simulation essentially replaces the hands-on lab, but also 
in those cases where the simulation can extend the experience from 
the hands-on lab to areas that cannot conveniently be investigated 
directly.

A side-benefit of the use of simulations, especially to demonstrate 
non-physical phenomena is to remind the students that simulators are 
not always going to give you what you should see in the real world, 
and that even the best of them will be limited by the accuracy of the 
model used to build the simulation.

So, in the time-honored language of Grant Swinger, "We need more 
research on this subject."

Hugh
--

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Hugh Haskell
<mailto:haskell@ncssm.edu>
<mailto:hhaskell@mindspring.com>

(919) 467-7610

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