Date: Fri, 27 May 2005 14:43:33 -0600

Author: "Zigmund J. Peacock"

Subject: Re: TIR Demo


Judy, I built one years ago and replaced it just last year.
It was the last demo built by the legendary demo guy at Minnesota
Bruce Eaton who past away of cancer shortly after building the first one
I know of.
I use 6" diameter plexiglass tubing about a foot long with a 3/8th"
wall or 1/2".
To make the notch I set it in a mill with a couple of spacers under
one side and slowly cut the notch.
To polish the notch I first wet sanded the surface with 400 the 600
grit wet and dry sandpaper then gave it the final polish with
lapping/polishing compound. If you don't have lapping/polishing compound
available I'll send you some and a polishing pad.
After this use it memory of Bruce who was the consumate demo
builder. We refer to the demo as the Bruce Eaton thing/demo here.
Please excuse the standard units everything you need is sold in
these units.
I have send you a photo direct not through TAP-L

Email or call me if you need more help. Zig

Judith Elwell wrote:

> A professor wants a demonstration of total internal reflection. The
> idea is to point a laser at an angle towards a notch in the top of a
> plastic cylinder. The laser light then spirals down around the
> cylinder. The cylinder should be big enough for a classroom to see
> it-about 30 cm tall, 20 cm diam.
> Are there any suggestions about how to build one, such as, type of
> plastic, minimum thickness of cylinder, any other consideration.
> Thanks,
> Judy

Zigmund J. Peacock
University of Utah/Physics
115 SOUTH 1400 EAST #201 Tel 801 581 6602
SALT LAKE CITY UT 84112-0830 Fax 801 581 4801

"We sleep safely in our beds because rough men stand ready in
the night to do violence to those who would do us harm"
-- George Orwell

"All that is necessary for the triumph of evil is that good
men do nothing!"
-- Edmund Burke

From Sat May 28 08:44:19 2005