What is heat?

[DrRocket]

So if I compress a bottle of gas, and it becomes warmer due to the increase in pressure, it will never cool down unless the valve leaks?

 

 

Sort of puts the old kibash on refrigeration technology doesn't it ?

[Tom Booth]

Pump or compressor. Keep the volumes in a temperature bath, like ice water.

 

Real scientific there swansont.

 

I think I've already acknowledge that reaching such a condition is possible, if extra heat is added to one of the containers, (rather than doing the experiments in a vacuum or otherwise having the containers insulated against outside heat exchange).

 

In your scenario, the excess heat from compression in one container (or both) is removed with ice, presumably.

 

So why the ice ?

 

True, temperatures will equalize, but isn't your use of the ice bath an admission that the temperatures have to be artificially manipulated somehow to bring the two back into thermal equilibrium while being compressed?

 

Cooling two containers back to equilibrium with ice does not disprove the kinetic theory IMO, if that is your intention, which seems vaguely to be the case. Though what your actual position on anything might be is impossible to say since it changes with the wind.

 

"The pressure of a gas of fixed mass and fixed volume is directly proportional to the gas's absolute temperature."

 

A pity you didn't actually read the link. It was the second sentence in that section. The example under discussion does not refer to containers of equal volume.

 

You have swopped out the words "fixed" and "equal".

 

"fixed" and "equal" don't mean the same thing.

 

No, it does not refer to containers of equal volume, but it does refer to containers of "fixed volume" as it has been repeated here several times, including by yourself that the containers are of different size yes, but that there is no change in volume.

 

Your words:

 

"The example was two containers. Not one container undergoing expansion or contraction. There is no change in volume, there is a difference in volume."

 

"No change in volume" = "fixed volume" No?

 

What has been described is two different containers, each with its own fixed mass and fixed volume.

 

If allowed to sit at ambient for some time Do temperatures equalize?

 

I would think so.

 

Can the heat from compression be lost, Sure.

 

So, in the example given, the bigger container ends up with a lower pressure. Can we agree on that?

 

The smaller container has a higher pressure if both containers contain the same number of atoms right ? That is; if the temperature is allowed to equalize.

 

The individual atoms in the smaller container would then have less "internal energy" (as this was dissipated as heat to the surroundings). The individual atoms in the larger container would have more "internal energy" which they picked up from the surrounding environment.

 

So each could be at the same temperature, once allowed to equalize with the surroundings, ice bath, ambient or whatever but would not have the same "internal" kinetic energy.

 

To prove this, if the volumes of substance were released back into equal size containers (the containers held in a vacuum or otherwise insulated against external heat exchange) the gas from the smaller container would end up colder than the gas from the larger container.

 

Again, refrigeration comes to mind.

 

I don't really know what it is you are trying to prove or disprove, if anything, one way or the other swansont but it seems to me your supposed stance or opinions or certainties on any subject are more or less a shifting sand.

 

The original question was, "what is heat".

 

You said "light from the sun is heat".

 

I pointed out laser cooling.

 

You say ""I didn't say "light is heat". I said the light from the sun is heat. It's a very important distinction"

 

Then end up by quoting:

 

" "Any object at any temperature emits electromagnetic radiation" "

 

So where is the "very important distinction" ?

 

Is a Laser a form of electromagnetic radiation ?

 

Is electromagnetic radiation in any form "Heat", except for lasers ?

 

Round and round we go.

[Cap'n Refsmmat]

Sort of puts the old kibash on refrigeration technology doesn't it ?

I dunno, I'd like to buy a few bottles from his supplier.

[DrRocket]

I dunno, I'd like to buy a few bottles from his supplier.

 

Whatever he is drinking is powerful stuff.

[finiter]

What you're describing is impossible. You cannot keep the energy the same while changing one parameter and keeping the other's constant. This is because work must be done on the system to force the gas into the smaller container size.

I think that you are suggesting that two containers having the same amount of gas, but different volume, can never have the same amount of energy( or have I got it wrong?). That implies that there is a limit to the energy that can be possessed by a body. Please clarify.

[Tom Booth]

...to contrast how heat is not internal energy...

 

Much of this discussion I think stems from miscommunication and as already stated, "sloppiness" in the thermodynamic lexicon. "Heat" as a verb should be replaced.

 

I have read (or heard in lectures) that the energy of a gas (including "internal energy") is in the form of "heat only". Mostly in connection with refrigeration. Specifically Air-Cycle refrigeration where a gas is expanded through a turbine and therefore, in performing work to turn the turbine, gives up "internal energy" and so grows cold, which is how the cooling in such a system is effected. This type of cooling is also one way that cryogenic temperatures can be reached as the gas is made to give up its "internal energy" by doing work to turn the turbine, which "internal energy" presumably refers to such "degrees of freedom" as "spin" or some other "internal" molecular energy.)

 

So I am curious about your statement that "heat is not internal energy".

 

As I understand it heat is "kinetic energy" regardless if that kinetic energy is "internal" or not.

 

That is, a particle can be moving through space as one form of kinetic energy but also has its "internal" kinetic energy which, if removed also lowers the temperature.

 

Can you elaborate on what exactly you mean by "heat is not internal energy".

 

Generally speaking I agree with the later part of your statement. In any case there are better less ambiguous terms.

 

This is why I say "heat" does not exist.

 

Light has physical properties, speed, charge, mass, spin etc.

 

Does "Heat" have any such physical properties whatsoever ? I have never heard of any such physical properties being attributed to "Heat" therefore in what way could it be said to exist (other than as a subjective impression caused by a transfer of kinetic energy from actual particles)?

 

I'm guessing that the reason a gas cools to an extremely low temperature in a cryogenic freezer utilizing an expansion turbine, upon being compressed and pre-cooled and then sent through a turbine is that in being ejected from a nozzle under pressure, the kinetic energies, including "internal" energies are, on average, due to their velocity, more inclined to give up the internal energy.

 

Like lets say "spin" is like my running in a circle.

 

If I were running in a circle on the deck of a boat going under a low bridge and ran into the bridge I would transmit more energy to the bridge than if I just ran into the bridge standing on the ground. In fact, if while on the ground I just ran in a circle without something to carry me along I would not hit the bridge or transmit any of my "internal" energy to the bridge.

 

Suppose I happened to be running AWAY from the bridge when the boat went under ? I would tend not to run into the bridge until I rounded the circle and started back towards the bridge. So my "internal energy" would be added together with the momentum or "external" energy of being carried along by the boat.

 

The molecules being ejected from a turbine nozzle into a turbine are, as if, riding on a "boat" due to the velocity of the mass of air carrying them along. There is therefore two kinds of kinetic energy being given up when they hit the "bridge" (the turbine blades). The result being an extreme drop in temperature.

[DrRocket]

I think that you are suggesting that two containers having the same amount of gas, but different volume, can never have the same amount of energy( or have I got it wrong?). That implies that there is a limit to the energy that can be possessed by a body. Please clarify.

 

That is not at all what swansont is suggesting. What he is stating very clearly is that thermodynamics does not allow what you are suggesting.

 

There are many good texts on thermodynamics. Two good ones are Thermal Physics by Morse and Elements of Thermodynamics and Heat Transfer by Obert and Young.

 

You are in desperate need of reading a book on the subject.

[Tom Booth]

 

http://en.wikipedia.org/wiki/Black_body

http://hyperphysics.phy-astr.gsu.edu/hbase/mod6.html

http://www.engineeringtoolbox.com/radiation-heat-transfer-d_431.html

 

If I took the time to read all your supposed references above that presumably are meant to support some one or more of your contentions I'm quite sure I would find that no such support exists therein.

 

How about a specific quote? I'm not going to do your work for you reading everything on the internet to try to find where someone else says something somewhere similar to your

"a laser is not a source of thermal energy".

 

Or:

 

"I didn't say "light is heat". I said the light from the sun is heat. It's a very important distinction — "

 

Your only direct quote thus far refutes any such distinction. (i.e. "

"Any object at any temperature emits electromagnetic radiation")

 

(Hint: when citing a reference you want to find one that supports your argument not one that contradicts it.)

 

Or: "the sun is emitting blackbody radiation because it's a thermal source and much hotter than its surroundings."

 

Can you please quote a passage from one of your above (or other) sources that give the same or a substantially similar definition of "blackbody radiation" i.e. a blackbody consists of: "a thermal source much hotter than its surroundings".

 

Or specifically that light or any other form of electromagnetic radiation "IS HEAT".

 

I used the sun as an example. I didn't say it was the only source of blackbody radiation.

 

You certainly implied as much.

 

You don't feel warm when you go out and the sun shines on you? Ever notice how it cools off at night?

 

Again, the propagation of light is not "heat transfer" until the light hits something. Then there can be transfer of energy on impact which is IMO properly, "kinetic energy". How I "feel" is, as I've stated previously, a subjective impression.

 

I'm going to dismiss the remainder of your arguments as irrelevant as they do not address the issues or are contradictions of your previous statements.

 

Nope. Didn't say that about light bulbs. They are great thermal sources that happen to emit a little bit of visible light.

 

 

You can raise the temperature via means other than heat transfer (as defined/used in physics). Photons have energy. You can raise the temperature of a piece of metal by bending it, too, but that's from doing mechanical work, not transferring heat. http://en.wikipedia.org/wiki/Work_(thermodynamics)

 

 

If you go to Google and choose the "books" option, and type in "blackbody radiation" you get more than 400,000 hits. Here's College Physics, Volume 10 By Raymond A. Serway, Chris Vuille, Jerry S. Faughn

http://books.google.com/books?id=CX0u0mIOZ44C&pg=PA870&dq=blackbody+radiation&hl=en&ei=iCJQTuzGK8zq0QGEv-ClDw&sa=X&oi=book_result&ct=result&resnum=3&sqi=2&ved=0CDkQ6AEwAg#v=onepage&q=blackbody%20radiation&f=false

 

"Any object at any temperature emits electromagnetic radiation"

 

If you go to the next page they discuss the sun as one example, and how it emits thermal radiation.

[spin-1/2-nuclei]

Holy crap?! Seriously?!

 

I NEVER said liquid nitrogen tanks don't warm up to ambient temperature, what I said was they don't do this by themselves in the absence of some sort of equilibrium.

 

That was implied by what I said when I said that you can't keep the temperature the same in any two systems with the same amount of gas while changing only one other parameter (please see the example I gave with the soda bottle).

 

I incorrectly assumed that people here - since they are claiming to be experts - would have been familiar with a liquid nitrogen tank. Clearly I was wrong. Two things you need to know about a liquid nitrogen dewar. 1. they have vacuum systems. Why? 2. They have a pressure release valve. Why?

 

Thus, as I have been saying and saying - you need to have outgassing in the system to warm up a compressed gas to room temperature without a catastrophic failure or explosion. If you do not do that, as I said before with the example of a soda bottle being squeezed - you will get either an explosion or a structural failure.

 

Do you people realize that gasses expand when they warm? This, combined with other factors, are the reasons for why you cannot just change one parameter (volume by shrinking container size) and keep all the other parameters the same.

 

Therefore, Swansont is just wrong. You cannot have two samples of gas at a fixed amount in two different containers with the same temperature and pressure and volume. For starters the volume changes by virtue of changing the container. Moreover, if the temperature is different then the pressure will be different, all day every day.

 

Swansont is incorrect - what he is suggesting is impossible no matter how you slice it. Those gases at fixed amounts in different size containers cannot have the same temp.

 

It is also impossible, despite what some here have suggested - to warm a compressed gas to ambient temperature without a change in pressure. If you are intent on increasing the temperature without increasing the container size, then you will need to utilize outgassing - to lower the amount of gas molecules inside the container - unless the desired result is an explosion or structural failure. As I have been saying and saying..

 

Observe people,

 

"Since the liquid to gas expansion ratio of nitrogen is 1:694 at 20C, a tremendous amount of force can be generated if liquid nitrogen is rapidly vaporized. In an incident in 2006 at Texas A&M University, the pressure-relief devices of a tank of liquid nitrogen were malfunctioning and later sealed. As a result of the subsequent pressure buildup, the tank failed catastrophically and exploded. The force of the explosion was sufficient to propel the tank through the ceiling immediately above it.[6]" - http://en.wikipedia.org/wiki/Liquid_nitrogen

 

Pray tell - how does the pressure release valve on a liquid nitrogen tank work people? Please describe it without correlating it to outgassing (i.e. the release of gas from the system to lower the pressure)..

 

sigh.... I am in awe.. I don't even know what to say.

Edited August 21, 2011 by spin-1/2-nuclei

[swansont]

Real scientific there swansont.

 

I think I've already acknowledge that reaching such a condition is possible, if extra heat is added to one of the containers, (rather than doing the experiments in a vacuum or otherwise having the containers insulated against outside heat exchange).

 

In your scenario, the excess heat from compression in one container (or both) is removed with ice, presumably.

 

So why the ice ?

 

Why the ice? Because the conditions of the problem were that the two containers be at the same average KE. This guarantees that.

 

The issue is that there are multiple variables. If the conditions of the problem require that one of them be held constant, then you hold it constant. Thermodynamics is replete with examples that hold a variable constant, because you get different answers if it's allowed to vary (and often you can't actually solve it without holding a term constant) That's why there are adiabatic processes, isobaric processes, isothermal processes, etc.

 

So yes, it's real scientific.

 

 

True, temperatures will equalize, but isn't your use of the ice bath an admission that the temperatures have to be artificially manipulated somehow to bring the two back into thermal equilibrium while being compressed?

 

Cooling two containers back to equilibrium with ice does not disprove the kinetic theory IMO, if that is your intention, which seems vaguely to be the case. Though what your actual position on anything might be is impossible to say since it changes with the wind.

 

You recall incorrectly. Fortunately this is a written medium, and all you have to do is check back to previous posts. I was answering a specific question about whether the temperature would be equal under very specific conditions. You and spin-1/2 who have introduced extra conditions into the problem.

 

You have swopped out the words "fixed" and "equal".

 

"fixed" and "equal" don't mean the same thing.

 

Yes I did, and they are functionally equivalent considering the different circumstances. "Fixed volume" refers to one container. You and spin-1/2 seem to be insisting that you have to compress a volume to get to the conditions of the problem. The volume is not fixed, so the law doesn't apply.

 

No, it does not refer to containers of equal volume, but it does refer to containers of "fixed volume" as it has been repeated here several times, including by yourself that the containers are of different size yes, but that there is no change in volume.

 

Then why did you bring up compression?

 

The original question was, "what is heat".

 

You said "light from the sun is heat".

 

I pointed out laser cooling.

 

You say ""I didn't say "light is heat". I said the light from the sun is heat. It's a very important distinction"

 

Then end up by quoting:

 

" "Any object at any temperature emits electromagnetic radiation" "

 

So where is the "very important distinction" ?

 

Is a Laser a form of electromagnetic radiation ?

 

Is electromagnetic radiation in any form "Heat", except for lasers ?

 

Round and round we go.

 

All light is electromagnetic radiation.

 

EM radiation that comes from a thermal source is heat.

 

Now, if you take a logic class, you will discover that this does NOT imply that all light is heat. It has to come from a thermal source. The sun is a thermal source. A laser is not.

 

Do you people realize that gasses expand when they warm? This, combined with other factors, are the reasons for why you cannot just change one parameter (volume by shrinking container size) and keep all the other parameters the same.

 

Therefore, Swansont is just wrong. You cannot have two samples of gas at a fixed amount in two different containers with the same temperature and pressure and volume. For starters the volume changes by virtue of changing the temperature. Moreover, if the temperature is different then the pressure will be different, all day every day.

 

Swansont is incorrect - what he is suggesting is impossible no matter how you slice it.

 

I never said the pressures would be equal. I stated the opposite.

http://www.scienceforums.net/topic/59202-what-is-heat/page__st__40__p__622921#entry622921

http://www.scienceforums.net/topic/59202-what-is-heat/page__st__60__p__622968#entry622968

 

It is also impossible, despite what some here have suggested - to warm a compressed gas to ambient temperature without a change in pressure.

 

At no point in the statement of the problem was it stated that the pressure was constant. More than once I pointed out that P1 and P2 will be different. So where was this suggested?

 

If I took the time to read all your supposed references above that presumably are meant to support some one or more of your contentions I'm quite sure I would find that no such support exists therein.

 

If you aren't going to bother to bother to read the sources, then why ask for them? Why bother with all this if you aren't interested in learning anything?

 

Again, the propagation of light is not "heat transfer" until the light hits something.

 

If that were true then an object in deep space would not cool down, because the radiation it emitted would not have hit anything.

 

Most of the light from the sun doesn't hit anything in the solar system. Why doesn't it get hotter and hotter? It keep generating energy from fusion. How does it get rid of that energy and maintain a constant temperature, if the EM radiation it emits isn't heat transfer until it hits something?

[spin-1/2-nuclei]

You recall incorrectly. Fortunately this is a written medium, and all you have to do is check back to previous posts. I was answering a specific question about whether the temperature would be equal under very specific conditions. You and spin-1/2 who have introduced extra conditions into the problem.

 

You said the temperature would be equal - which it cannot as the pressures are different. An increase in pressure results in an increase in temperature. Things will eventually equilibrate in an unsealed container via outgassing - and thus the amount of gas molecules in one container are no longer the same as the amount of gas molecules in the other container. You cannot warm a gas without expansion, you cannot expand a gas in a container without increase the pressure. If it is sealed - i.e. - heating a closed system - you get an increase in pressure as a result of the increase in temp - which in unfortunate cases can result in explosion or structural failure.

 

At no point in the statement of the problem was it stated that the pressure was constant. More than once I pointed out that P1 and P2 will be different. So where was this suggested?

 

This is why you have no idea what you are talking about. It is not possible to increase the pressure without increasing the temperature when only one parameter is changed. In this case container size.

 

Yes I did, and they are functionally equivalent considering the different circumstances. "Fixed volume" refers to one container. You and spin-1/2 seem to be insisting that you have to compress a volume to get to the conditions of the problem. The volume is not fixed, so the law doesn't apply.

 

This makes no sense. You are the one adding extra parameters to the situation in order to try to make the impossible possible. It doesn't matter how you get those two containers to have the same amount of gas - getting them at the same temperature requires getting them at the same pressure - see how compression works - and equilibrating them to ambient temperature requires a change in more than parameter of the system, for example outgassing to reduce pressure in the smaller container - i.e. changing the amounts so that they are no longer fixed.

 

Semantics is not a substitute for valid science. What fixed volume - for a gas - can be had in different container sizes? Gasses expand to reach maximum entropy (i.e. they get as far a part from each individual gas molecules as allowed by the system) - unlike liquids - due to their increased kinetic energy relative to things in the solid and liquid state which only exert pressure on the part of the container they are touching - whereas gasses exert pressure on all points of the container in all directions.

 

EM radiation that comes from a thermal source is heat.

 

Now, if you take a logic class, you will discover that this does NOT imply that all light is heat. It has to come from a thermal source. The sun is a thermal source. A laser is not.

 

If you were to take a logic class - you will discover that simply saying something does not make it true. A laser can be a thermal source. This is the problem with trying to discuss advanced topics at an undergraduate level of understanding. Most people figure out during the PhD that there are plenty of exceptions and modern expansions on top of the basics.

 

Observe:

 

"We present a unique bubble generation technique in microfluidic chips using continuous-wave laser-induced heat and demonstrate its application by creating micro-valves and micro-pumps." - http://pubs.rsc.org/en/Content/ArticleLanding/2011/LC/c0lc00520g

 

OMG! Swansont these people did not get the memo about lasers not being a heat source, neither did the people below. And did you know many universities have laser thermal labs? For shame! They should be closed down for fraud! All of their data must be faked. Miserable creatures, if they were really experts in physics they should know that lasers are not a source of "heat", because they are not a "thermal source", right? Maybe you should take some time to school them on the way "reality" works.

 

"THERMAL LASER EXCITATION BY MIXING IN A HIGHLY CONVECTIVE FLOW" - http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4842113

 

"In this section the laser will be considered as a thermal source and not as a primary source of highly monochromatic coherent radiation." - http://docs.google.com/viewer?a=v&q=cache:baCcDQu9jMMJ:old.iupac.org/publications/analytical_compendium/Cha10sec316.pdf+lasers+are+not+thermal+sources&hl=en&gl=za&pid=bl&srcid=ADGEESjv1iBgUqWvJFW-txJ5NvfAmSDUbVcy1vUW85gh0epW4IKZY5Cct0EnnaCV8xkakSyjcre-At9iYvsEbcbfCDq0m3nr6vfSaDjVSGr-NtouJQMRQNDmQJbfwGTsI_AYrpNEtd5Z&sig=AHIEtbQhe34LapLo4hq2bkRnKIZPx9vC_A

 

 

LOL! sigh..

Edited August 21, 2011 by spin-1/2-nuclei

[swansont]

You said the temperature would be equal - which it cannot as the pressures are different. An increase in pressure results in an increase in temperature. Things will eventually equilibrate in an unsealed container via outgassing - and thus the amount of gas molecules in one container are no longer the same as the amount of gas molecules in the other container. You cannot warm a gas without expansion, you cannot expand a gas in a container without increase the pressure. If it is sealed - i.e. - heating a closed system - you get an increase in pressure as a result of the increase in temp - which in unfortunate cases can result in explosion or structural failure.

 

 

 

This is why you have no idea what you are talking about. It is not possible to increase the pressure without increasing the temperature when only one parameter is changed. In this case container size.

 

PV=nRT We keep T and n constant. Thus PV is a constant. If volume goes up, pressure goes down. That's TWO variables, not one.

 

Explain to me how this is "not possible"

 

 

This makes no sense. You are the one adding extra parameters to the situation in order to try to make the impossible possible. It doesn't matter how you get those two containers to have the same amount of gas - getting them at the same temperature requires getting them at the same pressure - see how compression works - and equilibrating them to ambient temperature requires a change in more than parameter of the system, for example outgassing to reduce pressure in the smaller container - i.e. changing the amounts so that they are no longer fixed.

 

Semantics is not a substitute for valid science. What fixed volume - for a gas - can be had in different container sizes? Gasses expand to reach maximum entropy (i.e. they get as far a part from each individual gas molecules as allowed by the system) - unlike liquids - due to their increased kinetic energy relative to things in the solid and liquid state which only exert pressure on the part of the container they are touching - whereas gasses exert pressure on all points of the container in all directions.

 

If the containers are different sizes, the volume is not "fixed" i.e. a constant.

 

If you were to take a logic class - you will discover that simply saying something does not make it true. A laser can be a thermal source. This is the problem with trying to discuss advanced topics at an undergraduate level of understanding. Most people figure out during the PhD that there are plenty of exceptions and modern expansions on top of the basics.

 

Observe:

 

"We present a unique bubble generation technique in microfluidic chips using continuous-wave laser-induced heat and demonstrate its application by creating micro-valves and micro-pumps." - http://pubs.rsc.org/en/Content/ArticleLanding/2011/LC/c0lc00520g

 

OMG! Swansont these people did not get the memo about lasers not being a heat source, neither did the people below. And did you know many universities have laser thermal labs? For shame! They should be closed down for fraud! All of their data must be faked. Miserable creatures, if they were really experts in physics they should know that lasers are not a source of "heat", because they are not a "thermal source", right? Maybe you should take some time to school them on the way "reality" works.

 

"THERMAL LASER EXCITATION BY MIXING IN A HIGHLY CONVECTIVE FLOW" - http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4842113

 

"In this section the laser will be considered as a thermal source and not as a primary source of highly monochromatic coherent radiation." - http://docs.google.com/viewer?a=v&q=cache:baCcDQu9jMMJ:old.iupac.org/publications/analytical_compendium/Cha10sec316.pdf+lasers+are+not+thermal+sources&hl=en&gl=za&pid=bl&srcid=ADGEESjv1iBgUqWvJFW-txJ5NvfAmSDUbVcy1vUW85gh0epW4IKZY5Cct0EnnaCV8xkakSyjcre-At9iYvsEbcbfCDq0m3nr6vfSaDjVSGr-NtouJQMRQNDmQJbfwGTsI_AYrpNEtd5Z&sig=AHIEtbQhe34LapLo4hq2bkRnKIZPx9vC_A

 

There is a distinction between heat and work in thermodynamics. A laser can cause the action of heating because it is a source of thermodynamic work, just like mechanical work can accomplish this. A laser can heat things up. So will a microwave oven. However, the radiation is not considered heat according to the thermodynamic definition of heat. Strictly speaking, it is considered work. There is a sloppiness inherent in the terminology such that means that "a laser heated this up" (which is more of a lay use of the word, even though scientists use this terminology) and the "laser light is not heat" (using the physics definition). Mixing the two to try and make a point is the fallacy of equivocation. It's pretty obvious from the context that the authors are saying that the laser is being used as an energy source as if it were a thermal source; the temperature increases, so it doesn't matter to the experiment. But sloppy phrasing does not mean that the laser is emitting radiation that approximates the blackbody radiation spectrum.

[spin-1/2-nuclei]

@swansont,

 

"explain to me how this is not possible"

 

What for? As Tom says clearly many people here like to draw circle. The answer to your questions and challenges are in the many examples provided to you as well as the many linked scientific papers and I believe Tom linked you to an experiment that should help clear this up for you.

 

Shrugs,

There really is nothing more that can be said. Best of luck with whatever you do professionally but this forum is not for scientists.

 

Even in situations where what's happening in reality is ambiquous, discussions in my lab, at conferences, and seminars do not degenerate into circular nonsense.

 

The reason for this being, at least where I am from, is people are willing to back their claims up with references and they avoid moving goal lines.

 

I guess this is because in research the discussions are about the advancement of science and not about being right.

Edited August 21, 2011 by spin-1/2-nuclei

[swansont]

@swansont,

 

"explain to me how this is not possible"

 

What for? As Tom says clearly many people here like to draw circle. The answer to your questions and challenges are in the many examples provided to you as well as the many linked scientific papers and I believe Tom linked you to an experiment that should help clear this up for you.

 

Shrugs,

There really is nothing more that can be said. Best of luck with whatever you do professionally but this forum is not for scientists.

 

Even in situations where what's happening in reality is ambiquous, discussions in my lab, at conferences, and seminars do not degenerate into circular nonsense.

 

The reason for this being, at least where I am from, is people are willing to back their claims up with references and they avoid moving goal lines.

 

I guess this is because in research the discussions are about the advancement of science and not about being right.

 

You can't advance science when you get the introductory physics wrong, and since there is an objectively right answer, it is about getting that right.

 

I'm not the one moving the goal line here. This is finiter's question:

 

Suppose you have two containers, one larger than the other. Let each contain the same number of atoms of the same gas, and let their average kinetic energies be the same. In that situation, will the both have the same temperature?

 

— There is no discussion about how you arrived at that condition. Thus, not being able to arrive there via one specific process is not disproof

 

— There is no mention of the pressure. It is a variable in this scenario, not a constant.

 

— Since the average KE is specified to be equal, this is the same as saying that T1=T2. finiter wants to know if this can happen. If it is not, we should expect some contradiction in manipulating the equations, like a negative value or divergent solution.

 

PV=nRT

 

Since n1=n2 and T1=T2, we can then state that P1V1=P2V2

 

Any contradiction here? I don't see one. What I do see is that the larger container will have a smaller pressure. Nothing unphysical about that; I have containers with various pressures around the lab, some at vacuum levels, some are pressurized. The only way to get any kind of contradiction is to add a constraint that is not mentioned in the problem. Additional constraints are unnecessary to arrive at a solution.

 

Do I really need to provide a reference for the ideal gas law, or are you willing to accept that as legitimate physics? Or the transitive property I used to manipulate the equations?

[mississippichem]

I have read (or heard in lectures) that the energy of a gas (including "internal energy") is in the form of "heat only". Mostly in connection with refrigeration. Specifically Air-Cycle refrigeration where a gas is expanded through a turbine and therefore, in performing work to turn the turbine, gives up "internal energy" and so grows cold, which is how the cooling in such a system is effected. This type of cooling is also one way that cryogenic temperatures can be reached as the gas is made to give up its "internal energy" by doing work to turn the turbine, which "internal energy" presumably refers to such "degrees of freedom" as "spin" or some other "internal" molecular energy.)

 

So I am curious about your statement that "heat is not internal energy".

 

As I understand it heat is "kinetic energy" regardless if that kinetic energy is "internal" or not.

 

Internal energy is a state function. It doesn't matter how I get from U⁰ to U_f. I think you may be confused about what internal energy is.

 

[math] \Delta U = q + w [/math]

 

[math] dU = dq + dw [/math] where dw is the differential of expansion work. The expansion work is given by:

 

[math] dw = - \int_{V_{0}}^{V_{f}}pdV [/math]

 

lets set [math] w=0 [/math] for the case of no expansion work being done on the system.

 

[math] dU= dq [/math]

 

[math] \Delta U = q [/math]

 

So only in the case of no expansion work being done on the system are the change in internal energy and heat the same thing.

 

As to your other example with the boat, remember that internal energy does not include kinetic energy from the motion of the entire system. A glass of water at 298K at rest and a glass of water at 298K moving at 10 m/s have the same internal energy (neglecting the super tiny relativistic effect).

 

The first law of thermodynamics tells us that work and heat are basically equivalent with respect to a system. Work just requires a force to be exerted over a displacement, heat does not. When the internal energy has changed and the volume has not (no work has been done), heat has happened. I use the strange syntax "heat has happened" for a reason. I'm saying the a non-work transfer of Joules has happened across the system barrier. That is heat. Not a substance, but a phenomenon where energy is transferred. You would do well to pick up a book before claiming that some crucial thermodynamic quality doesn't exist.

[Cap'n Refsmmat]

I NEVER said liquid nitrogen tanks don't warm up to ambient temperature, what I said was they don't do this by themselves in the absence of some sort of equilibrium.

What you implied was that it is physically impossible for the liquid nitrogen to warm up otherwise:

 

If the gas is in a pre-compressed bottle the only way it will cool down to room temperature is if there is outgassing - thus changing the size of the sample.

 

That's of course not true; it can warm up and increase the pressure indefinitely. The bottle merely explodes at some point during that process.

 

Perhaps you could be clearer in your explanations in the future to prevent this sort of problem. I understand liquid nitrogen bottles and how they work, so don't worry.

[spin-1/2-nuclei]

@swansont

 

Oh so now your two containers have external heat/cooling sources? If thats not moving the goal post what is? When did the original question say we could arbitrarily arrive at the conditions however we wanted to.

 

Moreover, I'm not the one getting the basic physics wrong. So yes when you claim two different sized bottles filled with identical amounts of gas have the same temperature and different pressures you need a reference for how you're pulling that off under the constraints of the question.

 

If you're claiming the question can be answered however we want then I say adiabatic heating/cooling makes more sense, since the poster never define conditions for an experiment.

 

The ambiguous part of this discussion is your ever changing undefined experimental conditions. Surely the responsible approach to answering this question - when there were no experimental conditions given in the question - is to define the ones you're using.

 

I defined mine as adiabatic conditions wherein the work done on the container to compress the gas is transferred into kinetic energy which in turn increases the temperature and the pressure while decreasing the volume.

 

You've consistently disagreed with this being possible, and moreover it is the experiment most in line with the conditions given in the question.

 

So yes, if you're going to disagree with commonly held principles such as adiabatic heating and cooling you need references.

 

If you're going to disagree with the common use of lasers as a heating source and even other scientists who state that lasers can be used as a thermal source under certain conditions then you have to provide sources for that too...

 

@cap,

 

Please tell me how you can heat something up to room temperature that is hotter than room temperature?

Perhaps you should be more clear...

[Cap'n Refsmmat]

Please tell me how you can heat something up to room temperature that is hotter than room temperature?

Perhaps you should be more clear...

Ah, I see. I should have quoted this instead:

 

For example, the cylinder of liquid nitrogen used for the laser in my lab remains the same really cold temperature while compressed inside the cylinder. That is to say it does not equilibrate and warm up to room temperature. That would be unfortunate for us.

 

...which implies that your liquid nitrogen cylinders never warm up if you do not open the valves. They do, of course, and the internal pressure of the bottle rises until a relief valve opens.

[swansont]

@swansont

 

Oh so now your two containers have external heat/cooling sources? If thats not moving the goal post what is? When did the original question say we could arbitrarily arrive at the conditions however we wanted to.

 

The question asked if it was true that the temperatures were equal, i.e. if it were possible. There are no restrictions listed on how you achieve that state. In fact, a good followup question to this would be about the process, and what conditions would have to be present for it to work.

 

Moreover, I'm not the one getting the basic physics wrong. So yes when you claim two different sized bottles filled with identical amounts of gas have the same temperature and different pressures you need a reference for how you're pulling that off under the constraints of the question.

 

If you're claiming the question can be answered however we want then I say adiabatic heating/cooling makes more sense, since the poster never define conditions for an experiment.

 

Applying adiabatic heating/cooling makes no sense to me, since an isothermal condition is specified.

 

The ambiguous part of this discussion is your ever changing undefined experimental conditions. Surely the responsible approach to answering this question - when there were no experimental conditions given in the question - is to define the ones you're using.

 

I defined mine as adiabatic conditions wherein the work done on the container to compress the gas is transferred into kinetic energy which in turn increases the temperature and the pressure while decreasing the volume.

 

And I agree that that's the wrong way to do it. But the problem isn't asking you to find ways for it not to work. The question is basically asking if one can prepare two samples in different-sized volumes, same number of atoms and same temperature. There are no other constraints. Is the answer to that yes or no?

 

You've consistently disagreed with this being possible, and moreover it is the experiment most in line with the conditions given in the question.

 

So yes, if you're going to disagree with commonly held principles such as adiabatic heating and cooling you need references.

 

The fact that it can't be done adiabatically does not mean it can't be done. I have ignored adiabatic heating and cooling because it's the wrong tool for the job. That's not the same as disagreeing with it.

 

If you're going to disagree with the common use of lasers as a heating source and even other scientists who state that lasers can be used as a thermal source under certain conditions then you have to provide sources for that too...

 

I thought I was quite clear in stating that lasers can heat things up, because "heat things up" means "raise the temperature." But in a thermodynamic sense, the energy transfer is work rather than heat, because the radiation is not due to the temperature of the laser. So I'm not disagreeing that this is a common use. I'm pointing out the ambiguity in the terminology.

[spin-1/2-nuclei]

...which implies that your liquid nitrogen cylinders never warm up if you do not open the valves. They do, of course, and the internal pressure of the bottle rises until a relief valve opens.

 

I disagree, I didn't say that it could never warm up to room temp, what I said is that it does not warm up to room temp in or lab (that would result in a nasty lab accident).

 

From the rest of my post, it is clear that I attributed outgassing to the cooling of the argon system, and that I was saying liquid nitrogen is able to remain cold in the cylinder despite the cylinder being exposed to ambient temperature.

 

Just like for some reason Swansont thinks I should adopt his reasoning for how to answer a question, some people here seem to think that context is not important.

 

Swansont is of course free to disagree with my interpretation of how the person expected the question to be answered, but he cannot disagree with the concept of adiabatic heating/cooling without providing references.

 

As I said before, in the context of the thread - "What is heat?" - answering the question with the concept of adiabatic heating/cooling makes more sense to me because it more clearly explains the relationship between "heat", kinetic energy, pressure, and temperature.

 

Can I boil water at room temperature, sure? But in the thread "At what temperature does water boil?" The most appropriate answer is 100C. They aren't asking at what temperature can I get water to boil if I'm using a vacuum pump.

 

You're not taking two identical containers of gas and compressing one of them without a change in temperature and pressure unless you are in the lab. In the real world if I cap two soda bottles and squeeze/compress one of the - the one getting squeezed and compressed is changing temp, pressure, and volume.

 

Cheers

 

@Swansont,

 

Sorry I did not see your reply before I posted the last comment.

 

If you're saying you agree with adiabatic heating but not my decision to use it to answer finter's question then I apologize that I've obviously misunderstood your position. This was not clear to me earlier.

 

Regarding the use of lasers as a thermal heat source - I agree that the term is ambiguous but either we need a new definition of heat source or we need a new term to describe the "other energy" that results when people use lasers in chemistry and other fields.

 

This is why I asked for a reference on this. I do a lot of work with chemical physics in my research and the physicist whose laser lab we often use in our research refers to lasers -under certain circumstances - as a "thermal source" as well.

 

At this point I'm hoping for a discussion not a debate. So, I'm not asking for a reference to insult your intelligence, but rather to obtain more information. Lately, many scientist - some of them physicists are now starting to refer to lasers as thermal sources. This is either because the definition of thermal source is changing in physics as well, or because they are incorrectly using the term.

Edited August 21, 2011 by spin-1/2-nuclei

[Tom Booth]

 

There is a distinction between heat and work in thermodynamics. A laser can cause the action of heating because it is a source of thermodynamic work, just like mechanical work can accomplish this. A laser can heat things up. So will a microwave oven. However, the radiation is not considered heat according to the thermodynamic definition of heat. Strictly speaking, it is considered work. There is a sloppiness inherent in the terminology such that means that "a laser heated this up" (which is more of a lay use of the word, even though scientists use this terminology) and the "laser light is not heat" (using the physics definition). Mixing the two to try and make a point is the fallacy of equivocation. It's pretty obvious from the context that the authors are saying that the laser is being used as an energy source as if it were a thermal source; the temperature increases, so it doesn't matter to the experiment. But sloppy phrasing does not mean that the laser is emitting radiation that approximates the blackbody radiation spectrum.

 

In your above post, you seem to be making some tentative acknowledgement that the problem or issue here is mainly a matter of making semantic distinctions dictated by the context.

 

To put this another way:

 

Lets say I have a brother whom we will call "Tony".

 

Tony, my brother joins the army. Where there are very strict rules.

 

It would not be proper etiquette perhaps for other soldiers to call my brother by his first name. In that context, that of the army, my brother is called "Private Booth" or some such.

 

Now my brother is overheard referring to a fellow private as "Bob" instead of using the proper and accepted terminology for that context. He should have used the phrase "private Jones".

 

So as punishment my brother is made to march around the grounds by himself for three hours.

 

Later the same day, he is marching in step with the other soldiers.

 

Later in life after leaving the army, perhaps my brother starts his own business. In that context he is called "Boss" or Mr. Booth or whatever.

 

My point being in all this that whatever the context or the "proper terminology" for that context, my brother is still my brother. The selfsame person.

 

Now, given that, I would also say that light in a laser is no different than light anywhere else as far as individual photons are concerned. Just as my brother marching by himself or marching in step with other soldiers is still the same person. Only the context is different.

 

Now using "the proper terminology" is a good thing as far as helping to define the context but it is IMO misleading when this is taken to extremes or when it is taken too literally.

 

I'm probably going to be ducking out of this conversation soon as I have some projects I'm working on and this is becoming a rather time consuming distraction but, for what its worth, I just wanted to make my position clear as far as "what is heat".

 

If we are going to say that "Heat" is Kinetic energy in one context, or ALMOST every other context, then for consistency I would think it makes sense to consider "radiant energy" or electromagnetic energy, light or photons, "Black body" or otherwise as also being conveyors of kinetic energy and not some distinct form of "Thermal" or "Radiant" energy or "Heat".

 

Now this may not be proper etiquette or may not be the accepted terminology for the context but IMO a Photon is a Photon and viewed in isolation a photon from a "Thermal Source" is entirely and completely indistinguishable from a Photon from any other source just as my brother marching in step with other soldiers is still my brother and still the same individual whether marching in step with other soldiers - which is comparable to laser light where the photons are "in phase" with one another or marching by himself or when acting in any other capacity or context.

 

When considering the question: "What is heat?" I assume that this is a literal question: "What IS heat?" and does not mean; "what is the proper or accepted terminology to use when referring to energy in one context or the other."

 

So what is heat ? What is it literally?

 

In most applications or in nearly every sort of context "Heat" is viewed as or has in fact been proven to be by experiment - Kinetic Energy.

 

I don't personally see any reason for making an exception when it comes to electromagnetic radiation or Photons in whatever context and in fact, this is how laser cooling is explained in all the references I've read on the subject. It is explained and explained quite clearly and completely IMO in terms of Kinetic energy. Considering that there is literally some difference between a Photon in a laser and a photon from some other "Thermal" source just leads to confusion and contradiction IMO.

 

I personally, for whatever it might be worth, find that the "kinetic theory of heat" can be applied most consistently and explains various unusual phenomenon like laser cooling quite satisfactorily whatever the context and find no need to postulate some special exception to the rule in the form of "Heat from Blackbody Radiation".

 

If that is the "accepted terminology" for that particular context, I would say that the "accepted terminology" is inconsistent with the facts.

 

Is there any sort of "photon detector" that can distinguish a photon from a thermal source i.e. a photon that is properly termed "Heat" in some specific context and a photon from some other source ?

 

Not that I've ever heard of.

 

"Heat" in every other context has, I think, been proven to be a transfer of "Kinetic Energy". This has been demonstrated in an untold number of experiments. The distinction or exception to the general rule when it comes to thermal "Radiation" is, IMO, a misleading semantic distinction and nothing more. Heat in any context is LITERALLY kinetic energy or particles in motion whatever the generally accepted terminology might be in any particular context.

[swansont]

In most applications or in nearly every sort of context "Heat" is viewed as or has in fact been proven to be by experiment - Kinetic Energy.

 

In the context of physics, it has a much more specific meaning than in lay use. Since this is the physics section of a science forum, I am going to give the physics definition. Other long-standing members have weighed in, and have concurred.

 

I don't personally see any reason for making an exception when it comes to electromagnetic radiation or Photons in whatever context and in fact, this is how laser cooling is explained in all the references I've read on the subject. It is explained and explained quite clearly and completely IMO in terms of Kinetic energy. Considering that there is literally some difference between a Photon in a laser and a photon from some other "Thermal" source just leads to confusion and contradiction IMO.

 

I personally, for whatever it might be worth, find that the "kinetic theory of heat" can be applied most consistently and explains various unusual phenomenon like laser cooling quite satisfactorily whatever the context and find no need to postulate some special exception to the rule in the form of "Heat from Blackbody Radiation".

 

You refuse to read the references I provided, nor are you seemingly willing to pick up an actual physics textbook, so your personal needs/preferences are quite inconsequential.

 

If that is the "accepted terminology" for that particular context, I would say that the "accepted terminology" is inconsistent with the facts.

 

Is there any sort of "photon detector" that can distinguish a photon from a thermal source i.e. a photon that is properly termed "Heat" in some specific context and a photon from some other source ?

 

A single photon? No. A collection of them? Yes. The spectrum either will or will not match up with the blackbody spectrum. But then, you can't really tell from a thermometer reading if an object's temperature has been raised by heat transfer or work done on it, either. The object really doesn't care how the energy is transferred. That's a distinction we make, to be able to solve problems and apply our knowledge. And for the people who actually do this, radiation is a form of heat transfer when it's due to a temperature difference.

[DrRocket]

http://hyperphysics....mo/heat.html#c1

http://hyperphysics....rmo/heatra.html

 

"Heat may be defined as energy in transit from a high temperature object to a lower temperature object. An object does not possess "heat"; the appropriate term for the microscopic energy in an object is internal energy. The internal energy may be increased by transferring energy to the object from a higher temperature (hotter) object - this is properly called heating."

 

Meanwhile, in physics, heat is as is defined in the hyperphysics links I just gave.

 

 

In the context of physics, it has a much more specific meaning than in lay use. Since this is the physics section of a science forum, I am going to give the physics definition. Other long-standing members have weighed in, and have concurred.

 

 

A single photon? No. A collection of them? Yes. The spectrum either will or will not match up with the blackbody spectrum. But then, you can't really tell from a thermometer reading if an object's temperature has been raised by heat transfer or work done on it, either. The object really doesn't care how the energy is transferred. That's a distinction we make, to be able to solve problems and apply our knowledge. And for the people who actually do this, radiation is a form of heat transfer when it's due to a temperature difference.

 

Right

 

[math]dU=dQ-dW[/math] (Q is heat flow into the system and W is work done by the system)

 

and the difference between Q and W is somewhat in the eye of the beholder, so long as one is consistent. When Gibbs formulated classical theremodynamics lasers were in short supply.

 

Whether you call incoming laser light heat or work is unimportant so long as you account for it and are consistent. To be consistent with text books and the literature, per Obert's book, "Heat is energy transferred, without mass transfer across the boundary of a thermodynamic system because of a temperature difference between the system and its surroundings."

 

However, as you observed the system does not really care whether the incoming photon originated in an incandescent lamp or a laser, and the effect on internal energy is the same whether it is heat flow into the system or work done on the system. But it must be one of the two and it cannot be both. Convention results in it being called work.

Edited August 21, 2011 by DrRocket

[Tom Booth]

Tom Booth, on 20 August 2011 - 11:01 PM, said:

Real scientific there swansont.

...

So why the ice ?

 

Why the ice? Because the conditions of the problem were that the two containers be at the same average KE. This guarantees that.

 

The issue is that there are multiple variables. If the conditions of the problem require that one of them be held constant, then you hold it constant. Thermodynamics is replete with examples that hold a variable constant, because you get different answers if it's allowed to vary (and often you can't actually solve it without holding a term constant) That's why there are adiabatic processes, isobaric processes, isothermal processes, etc.

 

So yes, it's real scientific.

 

A general rule in science is to, as far as possible, eliminate all possible variables except for the one under investigation. Introducing ICE or any other outside source of arbitrary interference, heat or "cold" is introducing additional variables. This is why I would consider such an experiment more "scientific" if the containers were placed in some form of heat isolation with no outside source of heat or "cold" to potentially skew the results. Your method of compressing gas into two containers while disguising or muffling the heat change and temperature difference generated by keeping the whole system in an ice bath may not violate the terms of the question but it is quite certainly "skewing the results" and no it is not at all "scientific: IMHO.

 

All light is electromagnetic radiation.

 

EM radiation that comes from a thermal source is heat.

 

Now, if you take a logic class, you will discover that this does NOT imply that all light is heat. It has to come from a thermal source. The sun is a thermal source. A laser is not.

 

 

Tom Booth, on 21 August 2011 - 01:16 AM, said:

If I took the time to read all your supposed references above that presumably are meant to support some one or more of your contentions I'm quite sure I would find that no such support exists therein.

 

 

If you aren't going to bother to bother to read the sources, then why ask for them? Why bother with all this if you aren't interested in learning anything?

 

I've been studying "all of this" rather diligently, reading and listening and trying to make some sense of it all. But some of your assertions fly in the face of everything I've come to understand and everything I've ever read on the subject over the past few years. The reason I have been studying all this is because I'm building a kind of heat engine as discussed in another thread which you may or may not be aware of.

 

I doubt you could cite any thermodynamic reference on the internet that I have not already studied in some depth, half a dozen times over. Most of the online references state more or less the same information over and over in more or less the same terms outlining the same principles which are not IMO actually all that difficult to understand.

 

Then you come along with some remark that seems to me to be completely out of left field and has no correspondence whatsoever with established facts as I have come to understand them.

 

Therefore, I am requesting specific quotations from ANY source, preferably authoritative, that specifically backs up your specific assertions as I have already outlined. Such as: "A laser is not a thermal source".

 

You say to me: "If you go to Google and choose the "books" option, and type in "blackbody radiation" you get more than 400,000 hits"

 

So what?

 

Great, so you should have NO PROBLEM backing up your assertion with a direct authoritative quotation that reads, in substance: "A laser is not a thermal source".

 

I see spin-1/2-nuclei has already cited several sources that state the exact opposite. i.e.: "...the laser will be considered as a thermal source..." etc.

 

You simply state that these sources don't mean what they say.

 

You have again repeated this as if it were gospel:

 

"The sun is a thermal source. A laser is not."

 

I'm not going to search through your 400,000 Google hits trying to locate something that isn't there. A search for such a statement on Google in fact turns up nothing beyond your own words in this forum.

 

It is so patently common for a laser to be used as a thermal source that there is a name for it. "Thermal Laser".

 

Put that into Google in quotes and it returns about 200,000 results. Though I'm sure with your rather twisted logic you will come up with some reason why a thermal laser is not a thermal source.

 

So forgive me if I'm not interested in "learning" by being sent on some wild goose chase to try and prove your "logical absurdity" for which you yourself can obviously find no support.

 

Tom Booth, on 21 August 2011 - 01:16 AM, said:

Again, the propagation of light is not "heat transfer" until the light hits something.

 

 

If that were true then an object in deep space would not cool down, because the radiation it emitted would not have hit anything.

 

Most of the light from the sun doesn't hit anything in the solar system. Why doesn't it get hotter and hotter? It keep generating energy from fusion. How does it get rid of that energy and maintain a constant temperature, if the EM radiation it emits isn't heat transfer until it hits something?

 

OMG.

 

This is exactly the kind of logical absurdity and contradictions I was talking about when trying to view "Thermal Radiation" as heat.

 

The issues you bring up above disappear when heat (including so-called "thermal radiation") is viewed in terms of kinetic energy.

 

I put "Heat Transfer" in quotes because it is only a manner of speaking. Technically IMO, there is no such thing, it is rather a transfer of kinetic energy.

 

Light is emitted. The photon is then zipping along at the speed of 700 million miles an hour. Seems to me that is a substantial amount of kinetic energy.

 

Heat ? No. Nowhere to be found. Kinetic energy ? Yes and plenty of it.

 

I don't really care if this squares with your way of thinking or not or with the conventional wisdom on the subject or the opinions of long time members of this particular forum.

 

I would be very much interested in any hard data or experimental findings that might shed additional light on the subject.

 

The actual hard data or experiments, and the explaination accompanying such experiments, such as laser cooling, IMO confirm my proposition. The idea that "Thermal Radiation" is somehow some other mysterious form of undetected invisible energy leads to irreconcilable absurdities such as your object in space that doesn't get cold until the "thermal energy" it is radiating hits something.

 

Certainly, whatever your definitions or suppositions, the electromagnetic radiation from the sun is in no way sensible as "heat" until it actually hits someones skin. Before that point it was not "heat" IMO, but rather kinetic energy. motion of a particle (kinetic energy) to the tune of 700 million miles an hour.

[J.C.MacSwell]

-----------------------------------------------------------------------------

Two containers

 

One larger, one smaller

 

Each contain the same number of atoms of the same gas

 

Average kinetic energies are the same. (with respect to the centre of mass and any macroscopic rotation)

 

These are given, axiomatic. They are what Finiter proposed.

------------------------------------------------------------------------------

 

 

Given all that, they will have the same temperature. (as Swansont stated)

 

Anyone who says they cannot is wrong.

 

Any additional set of assumptions about how they came to that state, that lead to the conclusion that they cannot have the same temperature, are a wrong set of assumptions.

 

That additional set of assumptions would contradict the given conditions.

 

Anyone who would assume those additional assumptions is confused, as making those assumptions is a failure in logic.

 

--------------------------------------------------------------------------------

 

Therefore the containers will have the same temperature...

 

...even if Spin 1/2 is a scientist, has a lab with leaking pressure bottles, pressure bottles with infinite R-factor insulation, or is about to receive a Nobel prize, and even if, regrettably, this hurts his feelings...

 

The containers described by Finiter will have the same temperature (IT"S A GIVEN)