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The AFU and Urban Legend Archive Science Glass Flow origins of claim
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The AFU and Urban Legend Archive Science Glass Flow origins of claim
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From: iayork@panix.com (Ian A. York)
Newsgroups: alt.folklore.urban
Subject: Re: Questioning 'authorities' - spin on glass
Date: 18 Apr 1997 14:41:03 -0400
In article <19970418174400.NAA11949@ladder01.news.aol.com>,
Lawson L <lawsonl@aol.com> wrote:
>
>One question that I do not see answered - or even asked - in the
>FAQs or the various "glass flows" threads is where and when did
>this definitive statement start? And why is the "example" almost
Perhaps you missed this line, in
<http://www.ualberta.ca/~bderksen/florin.html>:
"I also speculate that at the origin of the legend may have been a misreading/mistranslation of an influential paper by Gustav Tamman."
The article includes more on this speculation, under the heading "Origin of an Urban Legend?":
How did the "glass is a supercooled liquid" urban legend originate? It is possible it began with an erroneous reading of an influential book by Gustav Tammann (1861-1938), a German physicist who was among the first to study glass as a thermodynamic system (Tammann, 1933). I was unable to locate a copy of Tammann's book to verify this, so the following is speculation. One or two papers I consulted attributed to Tammann the statement "Glass is a supercooled [or undercooled] liquid." But, from other papers, it appears that what Tammann actually wrote was "Glass is a frozen supercooled liquid" [my emphasis]. My speculation is that an author misquoted Tammann, and this misquotation was repeated by later authors who, since copies of Tammann's book are rather rare, did not refer directly to Tammann.
Until about 20 years ago supercooling a glass melt was the only way to obtain glass, and the behaviour of melts as they passed through the glass transition (i.e., solidified) was very different from crystallization. But solid-state physics was almost entirely based on the study of crystalline solids, which made the behaviour of glass melts appear paradoxal. To emphasize this a professor would state "Glass is a liquid which has lost the ability to flow", and some undergraduate, with his mind more on the Friday night date than on the physics of glass, would remember only "glass is a liquid"... Perhaps now we can finally put this legend to its well-deserved rest.
I've referred to this article perhaps fifty times or so over the past year, and as well this, as well as several other potential origins, was cited in an appendage to the Thread From Hell about 6 months ago, while we speculated on the origins of the legend. Thus it's not quite true that the question of origins has not even been asked. Of course, it's most unlikely that a definitive answer will ever come to light, and you speculations are at least as likely as others'.
Ian
From: lawsonl@aol.com (Lawson L)
Newsgroups: alt.folklore.urban
Subject: Questioning 'authorities' - spin on glass
Date: 18 Apr 1997 17:44:56 GMT
One question that I do not see answered - or even asked - in the FAQs or the various ^Ñglass flows^Ò threads is where and when did this definitive statement start? And why is the ^Ñexample^Ò almost always windows? [Aside from the manufacturing irregularities.]
It's interesting that in all the ng postings the arguments and explanations proffered in support of the idea are actually more compelling *against* it.
I've been researching the origin for the past week; haven't found an answer yet, but I have come across a number of so-called "authoritative" vectors which I'm going to quote with a big warning at the top of each one so no one jumps off thinking that I'm offering these as "see, yes it does".
WARNING: Actual Quote from Mistaken "Authority"
>*Glass* is a substance that is hard, brittle, and usually
>transparent. Although it has many properties of a solid, it is really
>a very thick liquid. It is a super-cooled liquid, which means that it
>was cooled below its freezing point before it solidified.
[The glass entry goes on into explanation of amorphous, followed by *nine* pages of history and usage, none of which explains when, where or how these properties were discovered. The concluding paragraph "The Future of Glass" states]
>It is only within the last 75 years, however, that scientists have
>begun to understand the nature and possible uses of this material.
Source: 1975 edition of Encyclopedia Brittanica Junior (sitting pretty
much unused in my granddaughter's room)
A delightful irony, this entry is in volume 9, which on the spine says "Folklore - Gospel"
WARNING: Actual Quote from Mistaken "Authority"
>glass (glàs) noun
>1. Any of a large class of materials with highly variable
>mechanical and optical properties that solidify from the molten
>state without crystallization, <snip>, and are considered to be
>supercooled liquids rather than true solids.
The American Heritage® Dictionary of the English Language, Third Edition copyright 1992 by Houghton Mifflin Company. Electronic version licensed from InfoSoft International, Inc. All rights reserved.
WARNING: Actual Quote from Mistaken "Authority"
>glass, hard substance, usually brittle and transparent, composed
>chiefly of silicates and an alkali fused at high temperatures.
>Metallic oxides impart color. In prehistoric times objects were
>fashioned from natural glass such as obsidian (a volcanic
>substance) and rock crystal (a transparent quartz).
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The Concise Columbia Encyclopedia is licensed from Columbia University Press. Copyright 1995 by Columbia University Press. All rights reserved.
WARNING: Actual Quote from Mistaken "Authority"
>It holds water, it keeps the wind from entering your house and it
>improves vision. It is also a liquid. What is it?
>Glass has a variety of uses and it is difficult to imagine life without
>it. Its strength and appearance seem solid enough, however glass
>is actually a liquid with an extremely high viscosity. Viscosity is the
>internal friction of a fluid, which determines how easily a liquid
>flows. <snip> Glass has such a high viscosity that it is difficult to
>detect any motion at all. Yet, windows made over a hundred years
>ago actually can show signs of flow. <snip >
WICN Science Moment # 59 Run week of February 20,1994 This Science Moment has been brought to you by the New England Science Center in Worcester, Massachusetts, in collaboration with WICN Public Radio.
>Halliday & Resnick's freshman physics text (4th edition, 1992) claims
>that glass flows in windows (at the beginning of the chapter on fluids).
WARNING: Actual Quote from Mistaken "Authority"
>Rheology is the study of flow of matter. Flow is an everyday
>phenomenon;<snip>. Rocks don't seem to do much by
>comparison, but remember that geologic processes take place
>over hundreds of thousands to millions of years. <snip>
>One everyday example of flow in what we consider solid material
>can be found in an unexpected place. When you look carefully at
>the windows in an old house you may find that the glass distorts
>your view.
>The reason is that, with time, the glass has sagged under its own
>weight (driven by gravity), giving rise to a wavy image. If the
>window glass is very old, you actually find that the top part of the
>glass is thinner than the bottom part. Eventually, the glass should
>leave the window frame and form a glass ornament on the window
>sill.
>There is no immediate reason for concern, however, because this
>process will take many thousands of years.
copyright van der Pluijm and Marshak, 1996 from chapter 5. Rheology in "EarthStructure: An Introduction to Structural Geology and Tectonics" December 1996 Ben van der Pluijm and Stephen Marshak
found at http://www-personal.umich.edu/~vdpluijm/earthstructure.htm
BTW, there was also a "Corrections" page, so to be thorough I checked
it out but this is what it said:
>Earth Structure -- Corrections
>An Introduction to Structural Geology and Tectonics Note: only
>corrections that can lead to misunderstanding of the material are
>listed on this page. A record of minor errors is kept elsewhere.
>We would greatly appreciate hearing about any errors you have
>found.
>Please email your comments to Ben.
etcetera ...
Perhaps a more scientific person than I would like to contact Ben & Steve here? Maybe it's just one of the "minor errors"?
Linda "I just catch them, you'll have to scale and clean them" Lawson
[Anybody want more? I could get dessert]
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