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demonstrate aI like to start with a thought provoking demo that sets up the
lesson. example: Using the double concave mirror toy to
*********************************virtual image.
*********************************Why do you use a DOUBLE concave mirror?
Won't a single concave mirror do the job?
Herb Gottlieb from New York City
Where it is almost impossible to find a double concave mirror in our
science supply catalogs.
The double concave mirror can be set up so that the common axis of~
the mirrors is vertical. The available demos usually place a small (D
5 cm) hole in the center of the upper mirror. The focal lengths andrests
intra-mirror separation are set so that the edge of the upper mirror
directly on the edge of the lower mirror; when an object is placed atthe vertex
of the lower mirror (that is, resting directly on its surface), thethe
resulting image makes the object appear to float in mid-air just above
central hole in the upper mirror. It's quite startling to see theimage
(which is usually a pretty good copy of the object) floating there, andeven
more startling (to the uninitiated, at least) when they try to touchthe
image with their hand and find only empty air. It's really much morefun
than merely seeing one's reflection in a single mirror. I'd tell you********************************************
where to get one, but I don't have any catalogs handy at the moment.