Re: Double concave mirror toy

[kowalskil <kowalskil@MAIL.MONTCLAIR.EDU>]

Sounds like a very impressive exhibit designed
to generate questions and curiosity. It was Scott's
last sentence ("Took most everyone in the department
by surprise.") that made be expect something very
unusual. I guess an exhibit with mirrors is much more
effective than my setup with a lens.
Ludwik Kowalski

"Dr. Paul O. Johnson" wrote:

> The commercial Mirage is one of our most popular exhibits. The black flying
> saucer shaped double mirror is hidden inside a plywood box. The hole in the
> top mirror is immediately below a similar hole in the box top. A thin sheet
> of Plexiglas covers this hole to prevent small hands from entering.
>
> We use to have a quarter at the object position and our sign said that if
> the visitor could pick up the quarter at the top (the real image), he could
> keep it. After a year of that we put the original pink plastic pig in the
> object position and we now offer a free lifetime Science Place membership to
> anyone who can pick up the pig.
>
> We also have a small flashlight attached to the table with a thin cable.
> When the visitor shines the light on the image pig at the top, he sees
> "specular reflections" from the pig just as if it were a real object.
> Obviously, the rays from the flashlight pass through the real image and
> reflect from the two mirrors and from the object pig just as the rays from
> the ceiling lights do to create the image pig.
>
> The real image looks so "real" that, even with a well-drawn ray tracing
> diagram, we sometimes have difficulty convincing visitors that it's not
> magic.