Dai Scott on wed 31 oct 01
Can we agree that heat may travel omnidirectionally through a conductor,
such as a metal rod, but rises through the air? We could agree now, or on
the other hand, we could agree in two weeks, after the subject has been
thrashed to death----or we could agree to disagree.
Dai in Kelowna, BC, feeling in an agreeable mood.
"There is no right way to do the wrong thing."
potterybydai@shaw.ca
----- Original Message -----
From: "Klyf Brown"
To:
Sent: Wednesday, October 31, 2001 3:43 PM
Subject: Re: [CLAYART] cold studios
> John,
> I have never studied thermodynamics and have no degree in any
> sciences, but I have studdied five gallon buckets full of cold liquids
> for the last sixteen years. If I place a bucket on top of a heating device
> overnight I find the inside material to be nice and warm in the morning.
> If I place that same heating device on the TOP of the bucket of
> material overnight the contents will not be heated very much at all.
> My conclusion: heat rises.
> I use a small propane space heater in my shop in the winter (yes Mel,
> I am a total cold wimp). When I want to warm my hands I hold them
> a ways over the top of the heater and use the rising heated air. I have
> held my hands the same distance under the heater and I feel no heat at
> all.
> My conclusion: Heat rises.
> SNIP
> But the movement of heat energy really knows no direction. Heat
> energy
> >moves from areas of higher concentration to areas of lower
>
> I am curious about this John, if heat is omnidirrectional, how can I
> stand under the stack of a kiln at cone 10 and not get fried in all that
> falling heat?
> Klyf Brown, still wrongly believing that heat rises.
>
> 10/31/01 9:08:33 AM, John Baymore
> wrote:
>
> >
> >But there is that pesky law about heat rising.
> >
> >
> >Klyf,
> >
> >Actually... that is one of those things that everyone "knows" that isn't
> >exactly true .
> >
> >Hot gases, being less dense than the surrounding cold gases, rise.
> We
> >often "learn" this idea experientally from feeling the higher
> temperature
> >near the ceiling of a room, or feel the "heat" rising from a candle, and
> so
> >on.
> >
> >Convective heat transfer is what we are experiencing in this case......
> the
> >heat energy is transfered to the gases...... and the hot gases move to
> a
> >different place....taking some heat energy with them.
> >
> >But the movement of heat energy really knows no direction. Heat
> energy
> >moves from areas of higher concentration to areas of lower
> concentration.
> >Basic law of thermodynamics..... kind of like "water always flows
> downhill"
> >
> >
> >Conductive heat transfer makes illustrating this concept easier.
> >
> >Hold a steel bar in one hand horizontally and heat the other end with
> a
> >blowtorch. Eventually you'll have to drop it . Now (after it has
> >completely cooled) do it again holding the bar vertically and have the
> blow
> >torch heating the top. Takes the same amount of time until the "drop
> >thing" happens . Now do it again with the blowtorch heating the
> bottom
> >of a vertically held bar. Once again...same time.
> >
> >There are a couple of minute other phenomona that will affect the
> above
> >example very slightly........ but for all intents and purposes...... it
> >illustrates the point pretty well.
> >
> >
> >The ONLY reason I bring this up at all is that an accurate
> understanding of
> >heat energy transfer is an important thing to potters....as it relates to
> >building and firing kilns.
> >
> >So the heat transfered through the wall of a kiln doesn't care if it is
> the
> >arch, wall, or floor. If the temperature differential across the
> >refractory structure between hot face and cold face is the same......
> the
> >rate of heat loss through the wall will be the same. Again...couple of
> >other factors adjust this a tad in the practical application.... but
close
> >enough to true.
> >
> >This "common knowledge" about heat rising has led to countless
> kilns being
> >built that have underinsulated floors .... like 5 inches of hard
firebrick
> >when the decision has been made to construct the rest of the
> structure out
> >of 9 inches of insulating firebrick. Then the potter wonders why the
> >bottom tends to fire cold . Years ago, Rhodes' Kiln Book
> helped to
> >foster this problem with the some of the designs in it.
> >
> >
> >Best,
> >
> >..............................john
> >
> >John Baymore
> >River Bend Pottery
> >22 Riverbend Way
> >Wilton, NH 03086 USA
> >
> >603-654-2752 (s)
> >800-900-1110 (s)
> >
> >JohnBaymore.com
> >
> >JBaymore@compuserve.com
> >John.Baymore@GSD-CO.com
> >
> >"Earth, Water, and Fire Noborigama Woodfiring Workshop 2002
> Dates TBA"
> >___________________________________________________
> ___________________________
> >Send postings to clayart@lsv.ceramics.org
> >
> >You may look at the archives for the list or change your subscription
> >settings from http://www.ceramics.org/clayart/
> >
> >Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
> >
> >
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Jeremy McLeod on thu 1 nov 01
vince pitelka wrote:
> Hey, heat rises. Anyone who tells you different is trying to confuse the
> issue and is no doubt part of some sort of ultra right/left-wing plot
> involving a one-world government and a devious banking conspiracy.
This is one good 'splanation. Another might be flunking Physics
somewhere along the line?
Jeremy
linda blossom on thu 1 nov 01
Vince et al: my college science teacher said that heat doesn't rise. It
is displaced by the heavier, cold air. I think she has good logic here.
Linda Blossom
760-510-6488
240 S. Bent
San Marcos, CA 92069
lindablossom@att.net
www.nottinghamarts.org
----- Original Message -----
From: "vince pitelka"
To:
Sent: Thursday, November 01, 2001 6:14 PM
Subject: Re: heat rises, was cold studios
> Hey, heat rises. Anyone who tells you different is trying to confuse the
> issue and is no doubt part of some sort of ultra right/left-wing plot
> involving a one-world government and a devious banking conspiracy.
> Ever on guard -
> - Vince
>
> Vince Pitelka
> Appalachian Center for Crafts
> Tennessee Technological University
> 1560 Craft Center Drive, Smithville TN 37166
> Home - vpitelka@dtccom.net
> 615/597-5376
> Work - wpitelka@tntech.edu
> 615/597-6801 ext. 111, fax 615/597-6803
> http://www.craftcenter.tntech.edu/
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
vince pitelka on thu 1 nov 01
Hey, heat rises. Anyone who tells you different is trying to confuse the
issue and is no doubt part of some sort of ultra right/left-wing plot
involving a one-world government and a devious banking conspiracy.
Ever on guard -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Tommy Humphries on thu 1 nov 01
Spatially speaking...
Warm air rises...
Heat radiates.
Tommy.
----- Original Message -----
From: "Dai Scott"
To:
Sent: Thursday, November 01, 2001 1:54 AM
Subject: Re: heat rises, was cold studios
> Can we agree that heat may travel omnidirectionally through a conductor,
> such as a metal rod, but rises through the air? We could agree now, or on
> the other hand, we could agree in two weeks, after the subject has been
> thrashed to death----or we could agree to disagree.
> Dai in Kelowna, BC, feeling in an agreeable mood.
> "There is no right way to do the wrong thing."
> potterybydai@shaw.ca
> ----- Original Message -----
>
tomsawyer on fri 2 nov 01
When our temperature dips below 70 F, I turn the heat on in my studio along
with my overhead fans; the fans drive the heat downward and provides for
more efficient energy use. Of course the fans are great in the summer and
help in drying greenware. I was almost intimidated in writing this after all
this talk about "wimps". In sunny Florida.
Tom Sawyer
tsawyer@cfl.rr.com
Dewitt on fri 2 nov 01
At 21:10 11/1/01 -0800, you wrote:
>Vince et al: my college science teacher said that heat doesn't rise. It
>is displaced by the heavier, cold air. I think she has good logic here.
Sounds rather like saying that boats don't float, the water holds them up.
deg
>Linda Blossom
>760-510-6488
>240 S. Bent
>San Marcos, CA 92069
>lindablossom@att.net
>www.nottinghamarts.org
>----- Original Message -----
>From: "vince pitelka"
>To:
>Sent: Thursday, November 01, 2001 6:14 PM
>Subject: Re: heat rises, was cold studios
>
>
> > Hey, heat rises. Anyone who tells you different is trying to confuse the
> > issue and is no doubt part of some sort of ultra right/left-wing plot
> > involving a one-world government and a devious banking conspiracy.
> > Ever on guard -
> > - Vince
> >
> > Vince Pitelka
> > Appalachian Center for Crafts
> > Tennessee Technological University
> > 1560 Craft Center Drive, Smithville TN 37166
> > Home - vpitelka@dtccom.net
> > 615/597-5376
> > Work - wpitelka@tntech.edu
> > 615/597-6801 ext. 111, fax 615/597-6803
> > http://www.craftcenter.tntech.edu/
> >
> >
>____________________________________________________________________________
>__
> > Send postings to clayart@lsv.ceramics.org
> >
> > You may look at the archives for the list or change your subscription
> > settings from http://www.ceramics.org/clayart/
> >
> > Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
> >
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
---------------------------
Dewitt Gimblet
dewitt@texas.net
Austin, TX
---------------------------
Jeremy McLeod on fri 2 nov 01
linda blossom wrote:
> Vince et al: my college science teacher said that heat doesn't rise. It
> is displaced by the heavier, cold air. I think she has good logic here.
Good point! It's akin to the question, "Does the sun rise and set each day?"
No. The earth rotates and the sun comes into view each day, appearing
to rise above one horizon and set below the opposite one.
That cold air is just soooo pushy!
Jeremy McLeod
Steve Mills on sat 3 nov 01
In message , Dewitt writes
>
>Sounds rather like saying that boats don't float, the water holds them up=
>=2E
>
>deg
>
>---------------------------
>Dewitt Gimblet
>dewitt@texas.net
>Austin, TX
>---------------------------
But that's correct isn't it. When is a boat not a boat: when it's a
rock! density is all. :-)
--
Steve Mills
Bath
UK
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