Re: Virtual and Real Images

["Spagna Jr., George" <gspagna@RMC.EDU>]

Joel wrote:
-----Original Message-----
> From: RAUBER, JOEL [mailto:JOEL_RAUBER@SDSTATE.EDU]
> Sent: Tuesday, March 19, 2002 9:46 AM

> Nothing beats taking a converging lens and sheet of white paper and aiming
> them at a window so that a visible image of the outside world (trees other
> buildings, etc) is formed on the paper.  If you have a diverging lens with
> you find that you can not due this, despite the fact that *you* can look
> through the lens out the window and see the outside world.

Somewhat harder is to convince students that a converging lens used as a
magnifying glass is producing a virtual image.  I have students attempt to
locate the image by parallax - alternately view with right and left eye.  A
pencil outside the field of view of the lens can be moved to be the same
distance from the observer as the image (same parallax) - this will be
clearly behind the object.

*********************************************
"Artificial intelligence is no match for
natural stupidity."
                    -Anonymous
********************************************
George Spagna
Department of Physics
Randolph-Macon College
P.O. Box 5005
Ashland, VA 23005-5505
phone: (804) 752-7344
FAX (804) 752-4724
e-mail: gspagna@rmc.edu
http://www.rmc.edu/~gspagna/