-----Original Message-----
From: Kossom [mailto:MKossover@NEWMANSCHOOL.ORG]
Sent: Tuesday, March 19, 2002 6:58 PM
To: PHYS-L@lists.nau.edu
Subject: Re: Virtual and Real Images
Part of the problem is that the light can not be "seen" as it travels.
This can, to some extent, be remedied.
I take two point light sources, vertically separated by about a foot, and
gel them red and green. I cut a hole in a large project board and put a
large converging lens in the hole. Like so
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red light --> /\
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| | water sprayed here
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green light --> \/
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After extinguishing the overhead lights, I illuminate the point sources.
Then I spray water from a fine mister on the other side of the lens. The
cones of light can be clearly seen coming together at a focus and then
spreading out again. Further, the cones are colored red and green so that it
is obvious that top and bottom are flipped.
You can see a better description of this and two other optics related labs
(one like the one suggested by Robert Cohen) at my web site. If the
information is too cryptic, I can expand. I demonstrated the first one in
Philadelphia.