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In a message dated 6/28/2007 10:19:37 AM Central Daylight Time, 
[log in to unmask] writes:

We're redoing the casework of an old Exploratorium component called
"Whirling Watcher." It's a slotted disk with drawings of a humming bird.
When you spin the disk and watch the drawings through the slots in a
mirror, you see a flying humming bird rather than individual drawings.

Part of the original label describe the phenomenon this way:
"The light sensitive retina at the back of your eye reacts relatively 
slowly
to incoming light, so that a quickly changing image remains “inside” your
eyes for a moment after it is no longer in front of your eyes. This 
effect is
called “persistence of vision.”"

While researching something else, I came across an article that seemed to
say that this phenomenon is not, in fact, persistence of vision. 
(citation and
link below) Before I embark on a more thorough research effort on this
topic, I thought I would see if someone else has already looked into this
and decided to change (or not) their label copy.

Thanks for any incites you can share, or even a leg up on my eventual
research. I'd be glad to know that this paper does not apply to
phenakistoscopes, or that it is not known to be reputable. Mostly, I'm
starting from zero on a project I hadn't planned to undertake.

Alana Parkes
Exhibit Developer
Museum of Science
Boston

"The Myth of Persistence of Vision Revisited," Journal of Film and Video,
Vol. 45, No. 1 (Spring 1993): 3-12.
http://www.uca.edu/org/ccsmi/ccsmi/classicwork/Myth%20Revisited.htm

Thank you for this information.  It looks like the Orpheum Children's Science 
Museum will need to redo our exhibit sign for this display!  I think it might 
be wise to include the old concepts, as a way to point out the nature of 
science and how slow the public is to accomodate certain new findings.  That might 
provide an entirely different type of view point for older visitors.
 
Janine Prillaman
Exhibits Committee
Orpheum Children's Science Museum
Champaign, IL



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