Talk:Heat (disambiguation)
From Wikipedia, the free encyclopedia
 |
This page is part of WikiProject Disambiguation, an attempt to structure and organize all disambiguation pages on Wikipedia. If you wish to help, you can edit the page attached to this talk page, or visit the project page, where you can join the project and/or contribute to the discussion. |
[edit] Heat
I just performed a complex edit that I think will solve the problematic proposed merger of Heat (now Heat (thermodynamics)) with Thermal energy. While the merger could still be done (I will restore the tags) I now think that it might be better to keep the articles seperate at Thermal energy and Heat (thermodynamics) as they are different concepts - the first is a kind of internal energy, the second the transfer of that energy. Because of this change, Heat should be a disambiguation. The way, the truth, and the light 20:37, 18 June 2007 (UTC)
- Heat is not the same thing as thermal energy. Heat is the transfer of thermal energy. One is Q and the other is U. --ScienceApologist 21:08, 18 June 2007 (UTC)
-
- That's exactly what I said above as a reason for keeping them as separate articles. The way, the truth, and the light 21:10, 18 June 2007 (UTC)
-
-
- There exist no sources which confuse heat and thermal energy. Such a merger or confusion is inappropriate. --ScienceApologist 21:17, 19 June 2007 (UTC)
-
I think that The way, the truth, and the light's proposal is poorly considered. Heat is the transfer of thermal energy. End of story. --ScienceApologist 21:32, 19 June 2007 (UTC)
- Here's how the main statistical mechanics/thermodynamics text I used at university puts it (Waldram, The theory of thermodynamics, C.U.P., 1985; page 7):
-
- "... we find that when two systems are placed in thermal contact, energy frequently flows spontaneously from one system to the other, without action by the observer... Such a spontaneous movement of energy is called a heat flow, and heat entering one body from another is written q. (The word 'heat' is simply a name for internal energy when we are thinking of the energy as randomised and free to move from one part of the system to another or between systems. The use of this special term can be rather misleading. There is no special part of the internal energy which can be identified as the 'heat', and it must not be thought that energies entering as work and heat are stored differently inside the system.)
- This matches how I would use the word: movement or transfer of energy = "heat flow" or "heat transfer"; the energy that is moving across the system boundary = heat.
- So, to my mind, the opening words of Heat (thermodynamics) jar: "In thermodynamics, heat, symbolized by Q, is the transfer of energy..." -- IMO that is heat transfer. Jheald 23:26, 19 June 2007 (UTC)
- (Also, I would tend to use q or ΔQ, rather than Q, for a finite amount of heat being transferred -- it's not a state variable). Jheald 23:26, 19 June 2007 (UTC)
-
- The book I mention directly below uses Q for a finite amount of energy transferred, and q for an infinitesimal amount.--Starwed 07:17, 20 June 2007 (UTC)
-
-
- Ok, I'm a bit confused here. By the form of ScienceApologist's words, I would think that he's arguing with with The way, the truth. But in fact, their position on this matter seems to be the same. (Namely, that Heat and Thermal Energy are distinct topics.) If the matter of contention is that there should not be a disambiguation page, I think the layman's understanding of heat is closer to the definition of thermal energy, and that there should be some note of this.
-
- For reference, I found a section on this exact matter in Thermal Physics by Ralph Baierlein. In section 1.6 The meaning of words, he discusses the usage of the word heat.
-
Historically, the word "heat" has been used as a noun as well, but such use- although common- is often technically incorrect. The reason is this: there is no way to identify a definite amount or kind of energy in a gas, say, as "heat."
-
"Heat" as a noun flourished during the days of caloric theory, but by 1865 at the latest, physicists knew that they should not speak of the "amount of heat" in a gas. ...Usage that is technically improper lingers nonetheless...
-
Energy that is being transferred by conduction or radiation may be called "heat." That is a technically correct use of the word and, indeed, a correct use as a noun. Once such energy has gotten into the physical system, however, it is just an indistinguishable contribuation to the internal energy. Only energy in transit may correctly be called "heat."
- --Starwed 07:10, 20 June 2007 (UTC)
-
-
-
- It seems to me that (happily) that Baierlein quote is completely in tune with what I quoted from Waldram above: "There is no special part of the internal energy which can be identified as the 'heat' ... heat entering one body from another is written q".
-
-
-
-
-
- Either way, they seem to agree on the semantic point I wanted to flag, that the "energy being transferred" is heat, not the "energy transfer".
-
-
-
-
-
- Putting the language questions aside, the important physical point is that net heat transferred is not a state function of the system (dQ is not an exact differential) -- if the system can go in different ways from A to B, the change in internal energy U will always be the same; but one cannot uniquely say much of that internal energy change is represented by heat evolved or by work done. Heat evolution does not directly, independently relate to a change in any corresponding state variable (eg "thermal energy" (?) ). This is the crunchy point of real physics to bring out, the real point of misapprehension that needs to be identified and corrected. (Which AFAICS our articles at the moment don't really do.) Jheald 07:49, 20 June 2007 (UTC)
-
-
The current page now states that "Heat is the transfer of thermal energy." I agree with Jheald that this usage is incorrect. Heat, used as a noun, refers to the energy being transferred, not the process. I can't come up with a good wording this second, though, so thought someone else might take a stab at it? --Starwed 20:24, 21 June 2007 (UTC)
The current version, although it makes the sentance flow more smoothly, is a bit misleading.
- In thermodynamics, heat is energy which spontaneously flows from an object with a high temperature to an object with a lower temperature.
This implies that it's possible to identify which energy in an object is heat. (It's implicitly defining heat as energy which will flow in a certain circumstance, implying that it exists even outside that process.) The reason for the tense chosen by Jheald was to elminate this ambiguity; it's only proper to refer to energy as heat during the thermodynamic process. Yes, this makes it hard to word the sentance nicely, but I don't think that's an excuse to decrease the accuracy of the statement. --Starwed 17:28, 22 June 2007 (UTC)
- I think it's reasonable to say that the energy that will flow as heat is thermal energy, which is why the topics are connected. The way, the truth, and the light 06:42, 30 June 2007 (UTC)
Might it be helpful to describe heat as an "effect"? this would distance its association with "heat transfer" and could defined further as "an observed effect associated with a temperature difference"
