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Re: Jelly Side Down :{{



Hi,
I have thought about it. The extreme version of
these thoughts is to pose the jelly side down
problem to the lab class at the start of the term
and then break up the problem into simpler bits
like falling, rotations, torques, . . So most of
the terms labs help solve this question. About
2/3 of the way through the term one could then
answer the question.

Thanks
Roger Haar
U of AZ

Richard Hake wrote:

In his AP-Physics post of 08 Jul 2003 11:42:25-0500, David Young
wrote (slightly edited):

"After having breakfast this morning, it occurred to me that one could
teach some pretty good physics around the "Jelly side down" toast
landing phenomenon. Does anyone teach a lab, or do a demo with this?
Why does MY toast always land jelly side down? :{{"

See Robert Ehrlich's (1997) discussion in "Why Toast Lands Jelly-Side
Down." Ehrlich credits Ron Edge (1988) and Darryl Steinert (1996) for
the Newtonian analysis of this phenomenon.

For an educational lab on the jelly-side-down phenomenon (JSDP) see
Brekke (1996). For a JSDP song see Gemini (2003).

However, there may be far more to the JSDP than just Newtonian
mechanics ;->. The Resistentialists
<http://www.wordspy.com/words/resistentialism.asp> cite the JSDP as
evidence for their belief that INANIMATE OBJECTS ARE HOSTILE TO
HUMANS.

According to Paul Jennings (1963):

JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ
[Convincing evidence for Resistentialism is] provided by the famous
Clark-Trimble experiments of 1935. Clark-Trimble was not primarily a
physicist, and his great discovery of the Graduated Hostility of
Things was made almost accidentally. During some research into the
relation between periods of the day and human bad temper,
Clark-Trimble, a leading Cambridge psychologist, came to the
conclusion that low human dynamics in the early morning could not
sufficiently explain the apparent hostility of Things at the
breakfast table - the way honey gets between the fingers, the
unfoldability of newspapers, etc. In the experiments which finally
confirmed him in this view, and which he demonstrated before the
Royal Society in London, Clark-Trimble arranged four hundred pieces
of carpet in ascending degrees of quality, from coarse matting to
priceless Chinese silk. Pieces of toast and marmalade, graded,
weighed, and measured, were then dropped on each piece of carpet, and
the marmalade-downwards incidence was statistically analysed. The
toast fell right-side-up every time on the cheap carpet, except when
the cheap carpet was screened from the rest (in which case the toast
didn't know that Clark-Trimble had other and better carpets), and it
fell marmalade-downwards every time on the Chinese silk. Most
remarkable of all, the marmalade-downwards incidence for the
intermediate grades was found to vary exactly with the quality of
carpet.
JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ

As far as I know, the Clark-Trimble experiments have defied Newtonian analysis.

Richard Hake, Emeritus Professor of Physics, Indiana University
24245 Hatteras Street, Woodland Hills, CA 91367
<rrhake@earthlink.net>
<http://www.physics.indiana.edu/~hake>
<http://www.physics.indiana.edu/~sdi>

REFERENCE
Brekke, G. 1996. "Beginning Statistical Inquiries into the Scientific
Method: Jelly-Side-Down"; online at
<http://www.accessexcellence.org/AE/AEC/AEF/1996/brekke_method.html>.

Edge, R.D. 1988. "Murphy's law or jelly-side down," Phys. Teach.
26(6): 392-393. According to Ehrlich (1997) there's a small error in
Edge's final equation.

Ehrlich, R. 1997."Why Toast Lands Jelly-Side Down: Zen and the Art of
Physics Demonstrations." Princeton University Press. For a
description see <http://pup.princeton.edu/titles/5969.html>, pp.
75-77.

Gemini. 2003. "Songs for Teaching: Jelly Side Down Day"; online at
<http://www.songsforteaching.com/JellySideDown.html>:
"It's a jelly side down kinda day
It's a pass go and do not collect a thing kind of day
Down in the dumps, taking my lumps
It's a jelly side down kinda day."

Jennings, P. 1963. "The Jenguin Pennings: Report on Resistentialism"
online at <http://www31.brinkster.com/yewtree/resources/resistentialism.htm>.

Steinert, D. 1996. "It's not Murphy's law, it's Newton's," Phys.
Teach. 34(5): 288-289.