From: k-sub-d@ix.netcom.com
Date: Thu May 08 2003 - 10:07:48 PDT
Message-ID: <7665083.1052413643278.JavaMail.nobody@kermit.psp.pas.earthlink.net> Date: Thu, 8 May 2003 10:07:48 -0700 (PDT) From: k-sub-d@ix.netcom.com Subject: Image formation difficulties?
Hey Everyone!
I use cardboard and two straight pins to make a "rifle sight" tool to help students see how mirrors form images. They line the sight up with the image in the mirror and use a ruler to draw rays to the mirror and back to the object, as well as extending the line behind the mirror. Repeating this from two or more sighting positions for each point on your object gives intersections that show where the virtual image would be. Using a simple assymetric shape, kids can see how mirror images get "flipped". This has worked well for me for a few years now.
However, yesterday I ran into a problem I can't explain. I had one students who simply could not line up the sight. Even if someone else lined it up she would see multiple images. This persisted with one eye closed, then the other, then both open again. She was very disturbed that she had no success with the lab, and I can't figure out why she couldn't see the lined up pins. Any ideas or other hands-on image formation techniques would be appreciated.
I think I may try a laser pointer to use as the ruler guide, but I'm not sure.
Kevin Doyle
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