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Re: PARTICLE MODEL



Ian Cameron wrote:

I am looking for a piece of software like an applet to show motion
of
particles in a gas. The target group os 13-14 year olds. Any
suggestions
as to where to look?

Ian


I have written a stand-alone program that I believe could be used for
that purpose. It was written in Borland Pascal and compiled for MS-DOS,
and it will run in a DOS window under Windows. My intent was to
simulate the movement of electrons in a metal, but scattering
probabilities, speeds, etc. were chosen to encourage conceptual
understand rather than to be numerically exact. To my eye it could
easily be explained as showing Brownian motion.

At this stage there is basically no dialogue, as the program is designed
as a demo and not for use independent of the instructor. The age level
would depend on your explanation rather than on anything in the
program. The program shows particles moving around and randomly
colliding with invisible background objects. The probability of
scattering at each time step can be adjusted, and an acceleration
between time steps can be specified as well. Up to 12 particles can be
displayed, and the CM position of the set is also shown on the screen
(one of the components of the CM position is artificially constrained to
be at the center of the screen; the other is free to change). You can
show the paths that the particles have taken across the screen or show
only the current position of each particle; the display can be toggled
back and forth between the two views during a run.

If you (or anyone) is interested let me know and tell me if you can
handle attachments to EMail. If you can't, I believe I can get it onto
a Department machine that permits anonymous ftp, and I can no doubt
figure out how to put it on my web site. It's about time I learned how
to put it on a web page anyway.

I would be interested in suggestions for improvements. The program
works, remember, on IBM PC-compatible machines only, as I can compile
only to MS-DOS.

--
Maurice Barnhill, mvb@udel.edu
http://www.physics.udel.edu/~barnhill/
Physics Dept., University of Delaware, Newark, DE 19716