Date: Sat, 23 Oct 2010 00:26:13

Author: Donald Lynch

Subject: Re: Poisson's spot

Post:

We use a half inch diameter ball bearing.

http://www.physics.umd.edu/lecdem/services/demos/demosm2/m2-03.htm

Don Lynch
Physics Lecture/Demonstration Group
John S. Toll Bldg.
University of Maryland
________________________________________
From: tap-l-owner@lists.ncsu.edu [tap-l-owner@lists.ncsu.edu] On Behalf Of Keith Warren [keith.warren@ncsu.edu]
Sent: Friday, October 22, 2010 8:28 PM
To: tap-l@lists.ncsu.edu
Subject: [tap-l] Poisson's spot

So I tried to photograph this today and came up with this shot,

http://demoroom.physics.ncsu.edu/images/Poissons_spot.jpg

While the spot is definitely there, I was disappointed with the radial lines. I thought I would see concentric lines. This shot is with a push pin. I later shot with a BB glued to a microscope slide and saw the same thing (minus the needle on the bottom). Also, this shot was with a red pen laser dispersed through a pasco concave 72mm lens. For the BB shot I used a Helium Neon laser and the same lens and similar results.

Has anybody successfully photographed this before? If so, HELP.

Have a good weekend all.

-Keith
NC State



From tap-l-owner@lists.ncsu.edu Sun Oct 24 09:49:50 2010

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