Re: Virtual and Real Images

[Rick Tarara <rtarara@SAINTMARYS.EDU>]

----- Original Message -----
From: "Hugh Haskell" <hhaskell@MINDSPRING.COM>

> As I think about it, I recall that it is possible to create a real
> image in a concave mirror, but because of the geometry, it is
> difficult to display the image.

We have a great demo (fairly standard) based on this.  A black box about .5
m on edge, with a light socket on top.  The actual bulb (orange 'flame'
type) is mounted upside down inside the box.  The back of the box is open.
A concave mirror (actually a great old one on brass stand with wooden frame)
is positioned behind to form a real image (now upright) just at the position
of the empty socket.  Alignment is critical.  I place this at the back of
the lab.  As student enter the front door, I ask them to go back and unscrew
the bulb for me.  They get about half way to the box before the image
suddenly disappears on them.  Because they are viewing a real image it is
incredibly life-like.  Good fun.

Rick

**********************************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, IN 46556
rtarara@saintmarys.edu

FREE PHYSICS INSTRUCTIONAL SOFTWARE
www.saintmarys.edu/~rtarara/software.html
PC and MAC software
NEW! SIMLAB2001--AIR TABLE now available.
CD-ROMs now available
******************************************************