Message-Id: <3.0.32.19971004172343.0071e1a0@icefog.polarnet.com>
Date: Sat, 04 Oct 1997 17:23:49 -0800
To: coralz@exploratorium.edu, vsm@northstar.k12.ak.us
From: "J. Lahr" <jlahr@polarnet.com>
Subject: Free stuff
Hi Coral!
I sure enjoyed meeting you and Tien this summer at the Exploratorium.
You wrote "I'm currently compiling a list of good ideas for
getting science materials on the cheap, like RAFT and NASA
Teacher Centers and Photo developers for film cans."
At an Alaskan teacher workshop (POLARIS) this week, Ron Bonnstetter
(rjb@unlinfo.unl.edu) of the University of Nebraska demonstrated a great
method that he invented for making spinning illusions, such as Benham's
disk or the spiral effect. He glues the paper pattern onto a plastic
CD disk. Then he puts a penny through the center hole,
perpendicular to the surface of the disk, to make a handle for turning
on the top and a pivot point on the bottom. You have to heat the penny
with a torch for 10 seconds to get it to melt its way into position.
Anyway, Ron said that he gets the CD's from radio stations; these are
the demo CD's that they would otherwise toss out!
John
-- * John C. and Jan H. Lahr * * jlahr@polarnet.com * * P.O. Box 83245, Fairbanks, AK 99708 * * (907) 474-7997 * * http://www2.polarnet.com/~jlahr * * http://giseis.alaska.edu/Input/lahr *