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So you think you already understand it?Explain yourself.
Quote from: hamdani yusuf on 11/04/2022 13:02:44How much can we remove until the difference can no longer be ignored?It depends what you are doing.
How much can we remove until the difference can no longer be ignored?
Quote from: hamdani yusuf on 12/04/2022 07:56:10So you think you already understand it?Explain yourself.I asked if you are any clearer on what temperature is after these 10 pages of discussion. I didn't say anything about my understanding. So what do you think, any clearer?
Hi. A few people, including myself, are just getting a bit uncertain what it is you ( @hamdani yusuf ) are trying to do.As @Origin has mentioned there are 10 pages of stuff here now. If you (Hamdani) get an opportunity perhaps you could think about and write down a summary of the situation so far. You might include the following: 1. A short summary of what has been said or done so far and what you're happy with. 2. Some indication of what you're still uncertain of or would like to continue to discuss. 3. Some indication of your ultimate goal. For example, do you wish to present new ideas about what a temperature is? You don't have to do this, you can obviously do whatever you want. It's just that several people (including me) aren't following the thread well, several things are getting repeated and future comments are at risk of becoming off-target.Best Wishes.
Looks like what we've got here is a failure to communicate.
Let's get this straight. If I do X, then a lot of frequency spectra can be removed without changing the status as thermal radiation. On the other hand, if I do Y, then a slight changes of frequency spectra will make the radiation no longer thermal. The question will be, what are the criteria for actions in X and Y category?
Quote from: Bored chemist on 11/04/2022 13:12:55Quote from: Bored chemist on Yesterday at 13:12:17It depends what you are doing.
Temperature is mostly described as a measure of the kinetic energy of particles, which is related to their movements.
But so is the energy of vibrations of the molecules of the gas.
Whether or not a particular spectrum would be considered "thermal" or not, depends on the context.
Quote from: Bored chemist on 13/04/2022 10:54:25But so is the energy of vibrations of the molecules of the gas.Isn't vibration a kind of movement?
And half the time, that energy is potential energy stored in the springiness of the molecules.
And it's only "thermal" energy if the energy is (ideally) equally shared out between all these various forms.
Quote from: Bored chemist on 13/04/2022 10:54:25Whether or not a particular spectrum would be considered "thermal" or not, depends on the context.What's an example where a particular spectrum would be considered "thermal" in one context, but not in another context?
Quote from: Bored chemist on 13/04/2022 10:54:25And it's only "thermal" energy if the energy is (ideally) equally shared out between all these various forms.Since the ideal conditions are not usually met, then most of the time it's not considered as thermal?
Quote from: hamdani yusuf on 13/04/2022 22:56:32Quote from: Bored chemist on 13/04/2022 10:54:25Whether or not a particular spectrum would be considered "thermal" or not, depends on the context.What's an example where a particular spectrum would be considered "thermal" in one context, but not in another context? A bit of information reduces uncertainty by a half.Your statement contains one bit of information, regardless of its correctness. Namely, thermality of a spectrum is not solely determined by its spectral distribution. There's at least another factor to consider in determining thermality, which you called context. The same exact spectrum can have different thermal status depending on its context. Is there any additional information on the context which can reduce the uncertainty, and make our knowledge more precise?
A xenon arc lamp gives a fairly good approximation to thermal spectrum- unless you look near the emission lines at the right hand endhttps://en.wikipedia.org/wiki/Xenon_arc_lamp#/media/File:Xenon_arc_lamp_profile.pngThe visible radiation from the sun is close enough to a thermal spectrum to let us estimate the temperature of the sun's surface.But the emission lines were what allowed someone to demonstrate the existence of helium
A xenon arc lamp gives a fairly good approximation to thermal spectrum- unless you look near the emission lines at the right hand end
But sometimes, temperature is also treated as potential energy,
Quote from: hamdani yusuf on 13/04/2022 05:58:39But sometimes, temperature is also treated as potential energy,No. It is a measure of potential, not energy.
A thermal spectrum is a continuum. An actual spectrum may have discrete bits added or subtracted, or may be entirely non-thermal.