Date: Tue Apr 3 13:15:32 2007

Author: --- trappe

Subject: Re: Half a Dozen Double Slits

Bill: I think my earlier reply failed to go out.

Make your own slides using high contrast ortho film, and photographing
quality white paper with black lines drawn either by hand or by
computer. I used some old cal-comp machine lines when I did mine.

Just draw the lines several inches long across the short direction of
the paper, mount your camera on a copy stand (or use tripod legs),
**be sure to meter using a grey card to get 18% grey correction for
camera's automatic metering**. You can change the size and separation
by either making more drawings or by zooming with the lens or the copy
stand height from the paper.

Since the film is negative, your black ink lines will come out clear,
and the background of white will come out black.

You can reverse engineer your slit sizes and separations by doing the
lab, yourself. If you are really energetic, you can figure the ratios
of "enlargement" (reduction) from 8 1/2 by 11 paper to 24 by 36 mm
film. Remember, that how much you fill the frame alters those ratios.

Have fun. It is actually a lab you can get the students to do (making
their own slits) if you have a darkroom.

It is a simple step to multi-slit patterns, once you get started. Karl

Quoting Bill Norwood :

> Hi Tappers,
> One of our labs where non-major students build their own experiments, for a
> few years now, has called for the following configurations of double slits:
> 1. A set with slitwidth held constant, but with 6 measured separations.
> 2. A set with slit separation held constant, but with 6 measured slitwidths.
> I can't quite get this with the PASCO and Cornell offerings.
> Has anyone heard of anything that might work?
> Many thanks for any info.
> Bill Norwood
> U of MD Physics
> Elementary Labs