Talk:Heat/Archive 1

message: Where would brownian motion fit in here?
:I'm not sure this would be an appropriate place to discuss brownian motion.  While brownian motion is certainly a heat induced phenomenon, it is not really a principle characteristic of heat and introcuding it here would likely distract from the main topic at hand. --Matt Stoker
::I agree. Brownian motion occurs even when everything has reached equilibrium temperature.
Heat, on the other hand, has something to do with 2 bodies at different temperatures.
:::Then there's always Judge Joe Brown, who propbably deserves the last say on the matter.--Achim 22:11, 18 June 2007 (UTC)
thread_title:  [[Brownian motion]] 

message: That's a nice picture (the forged iron). Collabi 08:47, 23 August 2005 (UTC)
replies: text: Its from User:Fir0002, one of Wikipedia's more prolific photographers. You might like to check out his gallery of other photos. -- Solipsist 17:52, 23 August 2005 (UTC)
thread_title:  Forged iron picture 

message: I don't know where Radiation is supposed to link to but right now it only links to a redirection page. Then, when i click on thermal radiation (which I would figure it is) i get to something about the black hole. -- Dennis Schaaf
:It links to thermal radiation now. It looks good to me. --DavidCary 00:29, 19 January 2006 (UTC)
thread_title:  Radiation 

message: Thermodynamics is not a theory. Thermodynamics is a branch of physics studying energy and energy transfer. And there are laws of thermodynamics, not theories. While there are specific theories within thermodynamics (statistical theory, kinetic theory), they should not be conflated with thermodynamics itself.--JohnDO|Speak your mind 04:07, 25 January 2006 (UTC)
thread_title:  Thermodynamics 

message: The quote at the end of the first paragraph of the history ("All things are an exchange for die") seems bizarre -- did some prankster change it? --Harold Kyriazi
:Fixed (it should be the word "fire"); thanks:--Sadi Carnot 05:15, 25 July 2006 (UTC)
thread_title:  Heraclitus quote 

message: Shouldn't we change the: 
:"Heat can only be transferred between objects, or areas within an object, with different temperatures, and then only in the direction of the colder body (as per the Second Law of Thermodynamics)."
to
:"Heat can only transfer itself ..."
In the present state it indicates that it is impossible to transfer heat from a cold source to a warm source.  What is a heat pump or a fridge then?  It seems to me that heat only can't transfer itself spontaneously from a cold body to a hot body. Or does this interfer with the discussion if heat is only to be seen as "energy in transfer" rather than "energy"? User:TomTompa 08/06/06
::This is just a technical detail.  If we want to move heat in the other direction, e.g. refrigeration, we have to add energy to the process in the form of work.  See: second law of thermodynamics for clarification. Thanks:--Sadi Carnot 18:55, 7 August 2006 (UTC)
thread_title:  Can heat be made to flow from cold to hot? 

message: I think the two "other heat transfer mechanisms" are somewhat misplaced.  Latent heat is not a heat transfer mechanism, it is a property that can be used to enhance heat transfer, but ultimately the heat transfer happens by one of the other three.  A heat pipe is not so much a mechanism as a device that utilizes the other three mechanisms.
In fact, I think this article could be severely cut back to maybe the first four sections.  Heat transfer and latent heat already have their own articles and the "heat dissipation" section doesn't really fit at all.  Having just stumbled across this page I don't want to make such big changes without throwing the idea out there first though.BCAttwood 18:12, 21 August 2006 (UTC)
thread_title:  Other heat transfer mechanisms 

message: I´ve been doing some search for information in this subject and found a couple of available textbooks on the internet that will surely be usefull for expanding and also refining the concepts of heat transfer. 
Please look at:
A Heat Transfer Textbook, John H. Lienhard V, Professor, Massachusetts Institute of Technology.
*http://web.mit.edu/lienhard/www/ahtt.html
Wolverine Engineering Data Book II, Dr. K.J. Bell and A.C. Mueller:
*http://www.wlv.com/products/databook/databook.pdf
Wolverine Engineering Data Book III, Pr. John R. Thome:
*http://www.wlv.com/products/databook/db3/DataBookIII.pdf
Please comment what you think.
WiKimik 19:49, 6 September 2006 (UTC)
thread_title: References

message: User:Deglr6328, who states: “this picture is indeed quite wrong. you are looking at the super-deep UV (near x-ray) emission of highly ionized He in the corona in that image. thats not where most of the heat from the sun comes from” and User:128.151.43.177, who states: “WRONG image is taken in the deep ultraviolet range well beyond the thermal EM blackbody emission”, have problems with the “red” sun image (right) and want the “yellow” sun image (left) used in its place:
I feel the yellow image has little visual impact.  Until someone adds a reference stating that heat is defined only for certain frequencies, I will replace the yellow photo for the red one.  Red is associated with heat more so than yellow.  Thanks: --Sadi Carnot 03:01, 28 November 2006 (UTC)
thread_title: Sun heat image

message: The thumbed image claimed red hot iron had fast heat transfer due to radiation. Though red iron glows, the heat transfer is very slow from radiation alone. The quickest way to transfer heat is through conduction (i.e. touching). If this is wrong, feel free to correct my edit, but I'm fairly certain this is the case. falsedef 23:20, 17 March 2007 (UTC)
replies: text: Electric bars aren't fire. They conduct heat by touching the cookware to the iron itself. They produce resistance, which creates heat on the metal. There's some convection and radiation, but radiation is the lowest of all those. You can easily place your hand near glowing iron. Touching is when you actually receive enough heat to burn yourself.falsedef 09:07, 18 March 2007 (UTC)

text: Alright, I found a source: "Cooking on the stovetop utilizes conduction through a pan to heat the contents. In dry heat cooking, heat is conducted directly from the pan to the food, as shown in Figure 2.1. The heat is generated by resistive elements on electric stovetops."  In absence of a conductor, radiation might become the primary heat loss. I'd need to see a source for iron having "high rate of heat transfer" through radiation. falsedef 09:52, 18 March 2007 (UTC)

text: That's not a high rate, though. A high rate of heat transfer would need to be done through conduction. You can label it as the primary heat transfer in gas, but it's not high rate. When insulated, iron takes a long time to cool. No one uses hot iron rods as a radiative heat source. When radiation is needed for high heat transfer, then a filament like nichrome is used. The current text looks fine, though. falsedef 22:58, 18 March 2007 (UTC)
thread_title: Red hot iron