How a cooler body heats a warmer body.

keepit wrote:
Every object above absolute zero gives off em radiation. That radiation comes off in all wavelengths regardless of the temperature of the cooler body.

keepit wrote:
Certain of those wavelengths are compatible with the atomic structure of the warmer body and are therefore absorbed by the warmer body, thereby heating it.

keepit wrote:
That is how a cooler body heats a warmer body.

JackFou wrote:
If I wanted to nitpick I would say that the cooler body doesn't "heat" the warmer body but that the cooler body prevents the warmer body from cooling itself as effectively as it would without the cooler body present.
Also the radiation doesn't come off in all wavelengths. The wavelengths that are being emitted depend on the temperature of the object. That's why objects only slowly start glowing red and eventually white if you heat them to several hundred degrees Celsius and higher. Objects at room temp don't have enough energy to radiate in the visible region of the EM spectrum and beyond. This realization became known as the "ultraviolet catastrophy" and was in fact how we eventually discovered quantum menchanics.

The frequency with the highest intensity within that thermal emission spectrum is indeed a measure of the objects temperature according to Wien's law.

JackFou wrote:
Otherwise yes, that's how it works.

JackFou wrote:
There exists a pretty simple and almost cute visualization in in two parts online.

keepit wrote:
Jack Fou,
As i understand it from wikipedia the temp of an object determines how much of a given wavelength is emitted but that all wavelengths are emitted, albeit in small quantities (brightness) for some wavelengths.
Quote from Wiki, "Plank radiation is said to be thermal radiation, such that the higher the temp of a body, the more radiation it emits at every wavelength."

gfm7175 wrote: Still batting 0.000 I see........

IBdaMann wrote:
keepit is actually correct,

keepit wrote:...Certain of those wavelengths are compatible with the atomic structure of the warmer body and are therefore absorbed by the warmer body,....

IBdaMann wrote:1) photons of the lower temperature object are not absorbed by the higher temperature object.

JackFou wrote:
If I wanted to nitpick I would say that the cooler body doesn't "heat" the warmer body but that the cooler body prevents the warmer body from cooling itself as effectively as it would without the cooler body present.

tmiddles wrote:...deleted Mantra 20a2...

tmiddles wrote: I'd go simpler still and simply say that some radiance from the cooler body can be absorbed by the warmer body and converted to thermal energy.

IBdaMann wrote:

tmiddles wrote: I'd go simpler still and simply say that some radiance from the cooler body can be absorbed by the warmer body and converted to thermal energy.

... but would you go so far as to demonstrate this?

IBdaMann wrote:1) photons of the lower temperature object are not absorbed by the higher temperature object.

tmiddles wrote: As you know IBD I consider the situation we are both in now to be a perfect example of this.

tmiddles wrote: Now true this is a simple textbook example of thermal radiation passing between two bodies, ...

tmiddles wrote: My question to you, ITN, GG, GFM and the whole crew is this:What do you think happens to the radiance from the walls around you when it reaches your skin?

tmiddles wrote: You have never answered that simple question.

tmiddles wrote: I can tell you it is absorbed

IBdaMann wrote:

gfm7175 wrote: Still batting 0.000 I see........

Actually, mark the time, mark the date.

keepit is actually correct, irrespective of Wikipedia being his source.

keepit got something right so we need to acknowledge it.

His batting average is now 0.013
His player card is going to have to be updated.

Planck's law specifies the power of a specific wavelength emitted by a given body of a given temperature. The vast bulk of wavelengths get very, very close to zero, but no wavelength actually achieves an emission power of zero.

Of course, Kirchoff's law tells us that a body's absorptivity at a given wavelength will equal its radiativity at that wavelength and will reduce radiativity by a certain fraction (percentage) strictly between 0.0 and 1.0 ... but no wavelength can have a radiativity of zero, ergo no wavelength can ever have an emission power of zero.

keepit was correct, that all wavelengths are emitted and the temperature of the body determines how much of each wavelength, and that none are zero.


.

tmiddles wrote:

IBdaMann wrote:

tmiddles wrote: I'd go simpler still and simply say that some radiance from the cooler body can be absorbed by the warmer body and converted to thermal energy.

... but would you go so far as to demonstrate this?

As you know IBD I consider the situation we are both in now to be a perfect example of this. Our bodies are radiating ~700 watts out into the cooler room. We absorb ~600 watts from that cooler room.

tmiddles wrote:
Now true this is a simple textbook example (Body Physics: Motion to Metabolism by Lawrence Davis) of thermal radiation passing between two bodies, one cooler and on warmer, and I can't take credit for it:net-thermal-radiation-you-in-a-room-as-a-reference

tmiddles wrote:
My question to you, ITN, GG, GFM and the whole crew is this:
What do you think happens to the radiance from the walls around you when it reaches your skin?

tmiddles wrote:
You have never answered that simple question.

tmiddles wrote:
I can tell you it is absorbed because the emissivity of human skin in the infrared is measured at over 0.9

tmiddles wrote:
Also this:

IBdaMann wrote:1) photons of the lower temperature object are not absorbed by the higher temperature object.

is a weird fabrication on your part found nowhere else. It's not found in a single reference anywhere online (Google reachable that is).

IBdaMann wrote:

tmiddles wrote: My question to you, ITN, GG, GFM and the whole crew is this:What do you think happens to the radiance from the walls around you when it reaches your skin?

If I am not mistaken, they too are pulling up chairs in expectation of your fascinating and quite frankly historic demonstration of thermal energy flowing from cooler to warmer. I really don't think they are even remotely interested in any further thrashing over the topic of electromagnetic energy ... but I suppose it couldn't hurt to could ask them

Into the Night wrote:

tmiddles wrote:
My question to you, ITN, GG, GFM and the whole crew is this:
What do you think happens to the radiance from the walls around you when it reaches your skin?

Nothing.

duncan61 wrote: If the esky has one tiny piece of ice in it it is below zero often I see people tip the water out and put new ice bags in without chilling the cans first.If you have an esky with cold water in it why not drop all your cans in it and turn it to warm water and pull some heat out of the cans.Can someone explain why warm water takes longer to boil than cold water with the same energy input.

IBdaMann wrote:

duncan61 wrote: If the esky has one tiny piece of ice in it it is below zero often I see people tip the water out and put new ice bags in without chilling the cans first.If you have an esky with cold water in it why not drop all your cans in it and turn it to warm water and pull some heat out of the cans.Can someone explain why warm water takes longer to boil than cold water with the same energy input.

Warm water does not take longer to boil by conduction than cold water.

Cold water does not take longer to freeze by conduction than warm water.

Ice does imply a sub-zero temperature. Temperature is not the only factor in boiling and freezing.

https://www.youtube.com/watch?v=y4BGV7-1lhs


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tmiddles wrote:

IBdaMann wrote:

tmiddles wrote: My question to you, ITN, GG, GFM and the whole crew is this:What do you think happens to the radiance from the walls around you when it reaches your skin?

If I am not mistaken, they too are pulling up chairs in expectation of your fascinating and quite frankly historic demonstration of thermal energy flowing from cooler to warmer. I really don't think they are even remotely interested in any further thrashing over the topic of electromagnetic energy ... but I suppose it couldn't hurt to could ask them

Oh the "You" there was you IBD. I'm asking you. You still haven't answered.

tmiddles wrote: Is there some reason you refuse to answer this question IBD?

James___ wrote: This is where you show the ignorance of anyone posting in this forum. There are those who will try to reason with you but this post is your bait.

IBdaMann wrote:... you need to either demonstrate thermal energy flowing from a cooler body to a warmer body or accept as a predicate for discussion that it is impossible, in order to move forward.

tmiddles wrote: My question to you, [IBD] is this:What do you think happens to the radiance from the walls around you when it reaches your skin?

tmiddles wrote:

IBdaMann wrote:

tmiddles wrote: My question to you, ITN, GG, GFM and the whole crew is this:What do you think happens to the radiance from the walls around you when it reaches your skin?

If I am not mistaken, they too are pulling up chairs in expectation of your fascinating and quite frankly historic demonstration of thermal energy flowing from cooler to warmer. I really don't think they are even remotely interested in any further thrashing over the topic of electromagnetic energy ... but I suppose it couldn't hurt to could ask them

Oh the "You" there was you IBD. I'm asking you. You still haven't answered.

tmiddles wrote:

Into the Night wrote:

tmiddles wrote:
My question to you, ITN, GG, GFM and the whole crew is this:
What do you think happens to the radiance from the walls around you when it reaches your skin?

Nothing.

What does that even mean? It ceases to exist?

I was operating on the assumption radiance can only do the following when it encounters matter:
1- Reflect
2- Absorb
3- Transmit
4- A combination of the above

So what is "Nothing"?

duncan61 wrote:
If I put warm cans of beer at 30 degrees C in ice slurry that is -4 degrees the thermal energy transfers and the beer becomes cooler and the ice melts as it absorbs the thermal energy from the cans.Most eskys are around 60 litre with 40 litre of ice slurry so I can only realistically put abou 6-10 375 mm cans in which is 2.25 - 3 litres before the ice is now warm water and has lost the ability to make my beer at the temperature I wish to have it.Store bought bag ice is -2-3 degrees at best my homemade ice can be as low as -21 so lots more energy fortunately I am a bush pig and will drink warm beer if stuck somewhere.Is this not an example of thermal energy transfer from one body to another.

tmiddles wrote:

tmiddles wrote:

IBdaMann wrote:

tmiddles wrote: My question to you, ITN, GG, GFM and the whole crew is this:What do you think happens to the radiance from the walls around you when it reaches your skin?

If I am not mistaken, they too are pulling up chairs in expectation of your fascinating and quite frankly historic demonstration of thermal energy flowing from cooler to warmer. I really don't think they are even remotely interested in any further thrashing over the topic of electromagnetic energy ... but I suppose it couldn't hurt to could ask them

Oh the "You" there was you IBD. I'm asking you. You still haven't answered.

Is there some reason you refuse to answer this question IBD?

tmiddles wrote:

IBdaMann wrote:... you need to either demonstrate thermal energy flowing from a cooler body to a warmer body or accept as a predicate for discussion that it is impossible, in order to move forward.

Accepted! If EM is defined as not being thermal energy then I do not now nor have I ever believed this statement: "thermal energy flowing from a cooler body to a warmer body", is possible. I have only ever said that radiance from a cooler body was absorbed by a warmer body and as you define the terms "thermal energy" and "flow" that is not the same thing. So in your vocabulary I accept your predicate.

Why don't we just clear this up and you can answer this very simple question to see if we actually disagree:

tmiddles wrote: My question to you, [IBD] is this:What do you think happens to the radiance from the walls around you when it reaches your skin?

tmiddles wrote: Accepted![/b]

Into the Night wrote:

tmiddles wrote:

Into the Night wrote:

tmiddles wrote:...What do you think happens...

Nothing.

What does that even mean? It ceases to exist? ...
So what is "Nothing"?

RQAA

IBdaMann wrote:
1. Thermal energy flows strictly from a warmer body to a cooler body.
2. Thermal energy does not flow between bodies of the same temperature.
3. Because of 1 & 2 above, since the thermal energy flow is not the difference between two separate energy flows moving in opposite directions, the flow is just that, a flow, and not a "net flow."

Once we have that, we will be golden and will have the green light to move forward.

tmiddles wrote:
If "Thermal energy" is defined as not including "radiance" then I do not believe, and have no reason to believe that the following statements are false.

tmiddles wrote: Now do keep in mind this is your rule for the definition of "Thermal energy" and not mine.

IBdaMann wrote:... but I did ask you to NOT present your statement in the form of a conditional or an "if" and I explained why, ...

Into the Night wrote:

keepit wrote:
Every object above absolute zero gives off em radiation. That radiation comes off in all wavelengths regardless of the temperature of the cooler body.

No, it doesn't. See Planck's law and Wien's law. Mantras 20v...29.

tmiddles wrote:And you asked that there be no "ifs" but you did not explain why.

39) Invalid proof
p) proof by irrelevance, i.e. presumed refutation is immaterial or unrelated, e.g. "you posted this at an odd hour," "I was right last time," etc..

tmiddles wrote:Your definition actually has no precedent and is just that, yours.

35) Claiming Opponent Holds a Minority View or Argumentum ad Populum

HarveyH55 wrote:...The thermal energy primarily comes from the sun, reasonably consistently. How much makes it to the surface, varies. CO2 does not create additional energy....

Into the Night wrote:...the high temperatures of Venus.