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

Author: Donald Lynch

Subject: Re: Poisson's spot


We use a half inch diameter ball bearing.

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

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

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.

NC State

From Sun Oct 24 09:49:50 2010