pdp1@EARTHLINK.NET on sat 7 jan 06
Hi Joseph,
Wonderful post...!
The "100" degree mark of Farenheit I think was arrived at by measureing the
temperature...within a delicate area of an amenible Cow...
Somehow, the Farenheit system always seems so friendly, innocent...wacky
even...
Where other systems, seemed somehow indifferent in their way, if possibly
more intentional or pedantic-methodolocial, in their reference-point's logic
and relation.
Water freezing at "0" and boiling ( well, at Sea Level, ) at "100" in
Celsius seems
to leave too few whole and impirically convenient degrees in-between...
...where, in the Farenheit way of faith, Water Boiling at '212'
and freezing at '32' seems, well, like he found out 'where' these events
happen...and with a decent amount of room in-between for other things to
happen, rather than to make their too cramped together occurance in his
scale 'be' the defining
milestones of the
callibration...
The difference is subtle - Farenheit's callibrations have a mood of
discocvery, and a mood inviteing discovery...openness, open-endedness...
Celcius seems closed off...decided in advance, and in some way, indifferent
and arbitrary in spite of being deliberate or intentional...'cramped'...
Anyway...great post...
I enjoyed it very much...
Phil
Las Vegas
----- Original Message -----
From: "Joseph Herbert"
> " I doubt that anyone can categorically state that either of the given
> examples is inherently more dangerous than the other. What is curiously
> common in them is the use of 0 C as an endpoint."
>
> I am a little hesitant to wade into this pond, things can get pretty
> philosophical pretty quickly.
>
> Temperature scales, in and of themselves, are harmless things; arbitrary
> divisions of the range of molecular velocities that we perceive as heat or
> temperature. Fahrenheit chose "blood heat" for 100 degrees and some other
> common "standard" and ended up with a degree size that had water freezing
at
> 32, water boiling at 212 and cone 10 at 2380. The more "rational" Celsius
> scale chooses water freezing for 0 water boiling for 100 and the two
scales
> meet at -40. All measuring the various degrees of molecular velocity.
Once
> the idea of no molecular movement sprang forth, no movement must mean no
> temperature or absolute zero and we have the Kelvin (Celsius sized
degrees)
> and Rankin (Fahrenheit sized degrees) scales with the absence of
temperature
> as their starting points.
>
> None of this matters until materials of construction and people become
> involved. We have expectations of how things will behave based on our
life
> experiences and most of those take place in a pretty narrow temperature
> band. Potters often deal with higher temperature, as do glass makers and
> metal workers. Even so, our expectations are built on the things we touch
> and move and eat.
>
> An example of the problem with our perception and how we loose our way
when
> conditions are outside our experience is the famous "Null ductility
> transition temperature." People had been building things of steel for
many
> years when WWII came along and got them to building more things faster.
> Also some of those things were sent places that there had not been so much
> of a need to go before. It happened that a ship, built of some particular
> composition of steel, was to join a convoy of ships going from Halifax,
Nova
> Scotia to England one winter. The ship, which had had some life in warmer
> climes already, came to the harbor, sat in the 30 (or -2) degree water and
> broke in half just sitting there. The investigation showed that the
square
> port that someone had made didn't help because it concentrated the
stresses,
> but the real reason the ship cracked apart and sank at the pier was the
> temperature of the water. The particular steel the ship was constructed
of
> had a peculiar property that caused it to loose ductility, the ability to
> deform without breaking, at a relatively high temperature. It turns out
> that many steels have this characteristic but at lower temperatures, not
> normally found in the world as we experience it. There was a feeling
among
> sailors at the time that some ships that were lost in the North Atlantic
> failed in this way rather than being lost to the weather or military
action.
>
> Certain stainless steels are mixed phases, two different structures in the
> one piece of metal. The proportion of these phases changes with
> temperature. Surprisingly, to us inhabitants of the narrow molecular
> velocity band, the change in proportions continues to change even as the
> metal is cooled to liquid nitrogen temperatures. These odd changes of
metal
> characteristics with temperature change and rate of temperature change has
> produced a myriad of names for heat treatment processes and their
products.
>
> In the case of glass, and ceramic glazes are mostly glass, the material is
> already a super-cooled liquid at "normal" temperatures. The molecular
> structure is disordered as in a liquid, and the properties of the material
> vary more or less continuously as it cools, there are no phase changes as
> glass cools. In that vein, there are no particular effects as the glass
> cools further. It is brittle at room temperature and is brittle at lower
> temperatures. One might find that the flexibility of glass, when cooled
to
> cryogenic temperatures, is less than that at room temperatures. After
all,
> at 1700 degrees, glass is pretty flexible.
>
> Anyway, my point here is that the concern is not with the changes in
> temperature, per se; it is with the effects on the particular materials
that
> are there when the change takes place. For some materials, it will matter
> not a bit; for others, it is catastrophe.
>
> The concept of temperature and the way we think about it is interesting.
It
> really is a measure of the velocity of molecular motion. For this reason,
> the temperature in outer space is often quoted as being rather high, like
> 50,000 degrees. Well, the occasional molecule that goes by is traveling
at
> a velocity that does translate to that temperature. The temperature of
that
> molecule is indeed that big number. We more often experience molecular
> motion in bulk, gasses that have enough molecules close together that we
can
> feel them on our face. Just in case you were thinking that the wind
blowing
> made the temperature hotter, molecules having "normal" temperatures are
> traveling at thousands of miles per hour. 3600 comes to mind.
>
> Our molecular velocity here is depressed slightly tonight. It will be
about
> 20 degrees.
>
> Joseph Herbert
>
>
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Snail Scott on mon 9 jan 06
At 09:42 PM 1/7/2006 -0800, Phil wrote:
>The "100" degree mark of Farenheit I think was arrived at by measureing the
>temperature...within a delicate area of an amenible Cow...
>Water freezing at "0" and boiling ( well, at Sea Level, ) at "100" in
>Celsius seems
>to leave too few whole and impirically convenient degrees in-between...
>
>...where, in the Farenheit way of faith, Water Boiling at '212'
>and freezing at '32' seems, well, like he found out 'where' these events
>happen...and with a decent amount of room in-between for other things to
>happen...
Shame on you, Phil!
There seems to be a persistent notion that the
Fahrenheit scale was arrived at by either random
assignment of numbers, or by arbitrary measurement
of naturally-occurring phenomena, or maybe sheer
ineptitude. Well, no.
Like many units of the 'English system', the
Fahrenheit scale is actually in fours and twos, not
in tens like the decimal system. The decimal system
is very amenable to mathematical calculation but
awkward for 'analog' situations. It really is
difficult to divide a physical thing (distance,
volume, etc) into ten equal parts, or even five.
(Remember high school geometry?) Division by twos
and fours is dead easy, though, and this is why the
'old system' was structured that way - not be hard
on the math, but to be easy in daily use. Divide a
gallon into quarts? No sweat, just half, then half
again. Pints? cups? Just repeat as needed.
The Fahrenheit scale was based on the freezing
points of water - distilled water, and a saturated
solution of salt water. Zero on the Fahrenheit
scale is the freezing point of the salt water.
The numerical temperature of distilled water was
chosen by simply creating 32 degrees between its
freezing point and zero. 32 - four times eight -
easy to divide into twos, or fours, or any other
binary increment. The rest of the scale, including
the boiling point of water, (which was known to
be variable, unlike the freezing point, and not
a reliable choice for a fixed point of empirical
reference) is merely derived from that choice,
and falls where it will. The hundred-degree mark
has no intentional correlation to anything in
nature, in spite of the seemingly too-close-for-
coincidence proximity of human (or animal) body
temperature.
We're accustomed nowadays, even in the US, to
units divisible by ten, and accurate rulers and
scales are readily available. But, in an era when
most things were measured hands-on without
finely calibrated measuring devices, and seldom
calculated mathematically, a system based on
halves made a lot of sense. As people who do a
lot of hands-on measurement, many of us can
appreciate the empirical simplicity underlying
the English system, even while we prefer metric
units for calculation.
-Snail
Snail Scott on mon 9 jan 06
At 07:45 PM 1/9/2006 -0500, you wrote:
>Snail Scott wrote:
>>The Fahrenheit scale was based on the freezing
>>points of water - distilled water, and a saturated
>>solution of salt water...
>Well, ahem. That's certainly a new one on me. Wikipedia
>(http://en.wikipedia.org/wiki/Fahrenheit) reports "several competing
>versions of the story of how Fahrenheit came to devise his temperature
>scale", but not that one...
Not claiming I'm absolutely right, though I
originally heard it from a physicist with an
interest in history. (Of course, Wikipedia is
not exactly a peer-reviewed journal, either.)
The salt-water story makes far more sense
than most other versions I've heard, but I'll
not insist upon it if someone has better
documentation for another origin. The more
information, the better! And the better
the information, the better, too! ;)
My principal point was that the inherent folk
logic of the English system of units is far
from 'irrational', and serves its users
differently from the decimal system. Worse
for many purposes, especially nowadays, but
still quite handy for others.
-Snail
Bruce Lucas on mon 9 jan 06
Snail Scott wrote:
>The Fahrenheit scale was based on the freezing
>points of water - distilled water, and a saturated
>solution of salt water. Zero on the Fahrenheit
>scale is the freezing point of the salt water.
>The numerical temperature of distilled water was
>chosen by simply creating 32 degrees between its
>freezing point and zero. 32 - four times eight -
>easy to divide into twos, or fours, or any other
>binary increment.
>
Well, ahem. That's certainly a new one on me. Wikipedia
(http://en.wikipedia.org/wiki/Fahrenheit) reports "several competing
versions of the story of how Fahrenheit came to devise his temperature
scale", but not that one. You might wish to contact the authors of the
article, or even better just edit it yourself (in the true wiki spirit),
to include your version.
Cheers,
Bruce Lucas
Ivor and Olive Lewis on tue 10 jan 06
Linus Pauling gives the history of the Fahrenheit scale as a footnote in =
this book, "General Chemistry". Zero was the lowest temperature that =
could be obtained at that time and was determined by the chap who =
invented the mercury in glass thermometer. The freezing mixture was =
Ammonium Chloride and Snow. Pauling speculates that by choosing 100 as =
"Body Heat" Gabriel Daniel F. may have had a fever.
It is indeed fortunate that 100 degrees on the Celsius scale is =
equivalent to 180 degrees on the Fahrenheit scale. make arithmetic =
conversions very easy.
Ivor Lewis.
Redhill,
South Australia.
Michael Wendt on tue 10 jan 06
Snail,
the version you gave corresponds with the version my physics instructor, Dr.
Ross Floyd, gave. He pointed out that at the time, scientists sought a
reliable means to reach a consistent low temperature for experiments in the
lab and the salt-ice reaction was the lowest temperature reliably reached
prior to refrigeration.
Regards,
Michael Wendt
Wendt Pottery
2729 Clearwater Ave
Lewiston, Idaho 83501
USA
wendtpot@lewiston.com
www.wendtpottery.com
Ivor and Olive Lewis on wed 11 jan 06
What is amazing about the Fahrenheit Scale is that after selecting the =
things that gave the lowest known reading and designating it as 0 =BA at =
that historic time and then making the freezing point of water as 32 =BA =
to simplify the counting is that there were exactly 180 similar equal =
incremental intervals from 32 to 212 where water turned to steam. The =
Centigrade scale has an inconvenience. At the bottom end, the absolute =
lower limit is just a fraction beyond minus 273. And at that temperature =
the F scale is inconvenienced, being minus 459.67=BA.
Such is the Beauty of Science.
Best regards,
Ivor
Bruce Girrell on wed 11 jan 06
I don't think there is much question about zero Fahrenheit being set based
on a salt/water freezing point. I think that the issue in question is
regarding the second point, whether it was 32 degrees, being chosen based on
a user friendly divide-by-two system, 100 degrees, based on body
temperature, or some other scheme.
[minor rant]
I read the Wikipedia history and was pleased to note the following:
"...the body temperature once taken as 96 or 100 °F by Fahrenheit is today
taken by many as 98.6 °F (it is a direct conversion of 37 °C, a case of
excess precision), although giving the value as 98 °F would be more
accurate."
Yes! Yes! Yes!
Someone else recognizes the concept of excess precision! It drives me nuts
to see a distance in inches converted to tenths of a millimeter or a weight*
in pounds being converted to fractions of a gram just because a calculator
lets you do it.
The study to determine average body temperature was done in Europe (hence
metric measurements were used) and, because body temperature varies quite a
bit from person to person, the results were averaged to produce a nice,
round 37 degrees. The direct conversion to Fahrenheit produces a value of
98.6 degrees, but the .6 is meaningless precision. A value of 99 degrees
would be just as valid and, from my experience with body temperatures, so
would a value of 98 degrees.
For a lot of things a small error won't make much difference. One-half inch
is a centimeter, 1/4 pound is 100 grams, a yard is a meter,...
It's not that difficult.
[/minor rant]
Bruce "whew! glad I got _that_ off my chest" Girrell
*Ivor - don't jump on me for this. I do know the difference between weight
and mass.
skiasonaranthropos@FSMAIL.NET on wed 11 jan 06
Hi Bruce,
You said " ... a small error won't make much difference. One-half inch is
a centimeter, 1/4 pound is 100 grams, a yard is a meter,..."
Best not mention that to NASA :-)
http://www.cnn.com/TECH/space/9909/30/mars.metric.02/
Regards,
Antony
Ivor and Olive Lewis on thu 12 jan 06
Dear Snail Scott,=20
Ency.Brit. confirms the salt and water source of the Zero reading and =
the 32 for the phase change of H2O. The salt has to be Ammonium =
Chloride. If Sodium chloride had been used Mr.F. would have finished up =
with a bastard of a number for the phase change of H2O. The Eutectic for =
NaCl and H2O which is Minus 21 deg C calculates to minus 5.8 deg F.
His choice of Ammonium chloride to mix with his Snow was either =
serendipity or the result of some very astute experimental work.
The Roman's used Snow from the Alps and Salt to invent "Ice Cream"
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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