Me and My friend are having a discussion about Absolute Temperature Scales. I think Absolute Temperature Scales are those who have their zero on Absolute zero. So Can we define a new Scale (say "Namu"), which is defined as $\frac{1}{8}*K$ where K is the Kelvin Scale, and say that this scale is absolute? If Yes, Can we really make temperature scales of our own (even if it won't be much significant)? Or are there some bounds place upon the creation?
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2$\begingroup$ Yes, that works. $\endgroup$– mmesser314Commented Feb 4, 2016 at 15:10
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$\begingroup$ @mmesser314.. was that an answer for both my questions? $\endgroup$– Prakhar LondheCommented Feb 4, 2016 at 15:17
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$\begingroup$ Please someone explain the downvote $\endgroup$– Prakhar LondheCommented Feb 4, 2016 at 16:06
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3$\begingroup$ There are two aspects to a temperature scale: 1) where you put the zero, and 2) the unit ( size of your degree). For an absolute scale there is only one choice for 1, but you are free to choose 2 however you like. $\endgroup$– Lewis MillerCommented Feb 4, 2016 at 16:07
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The term absolute isn't strictly defined, but most of us would agree that an absolute temperature scale has to have its zero at absolute zero.
You are free to define any unit of temperature you want. There is nothing special about the size of the degree Kelvin, it was chosen to be the same as the degree Celcius i.e. one one hundredth of the difference between the boiling and freezing points of water. Any temperature unit will work fine - degrees Fahrenheit are still used in the more backward parts of the world.
answered Feb 4, 2016 at 16:07
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$\begingroup$ So The "Namu" I defined can be considered an absolute scale, won't it? $\endgroup$ Commented Feb 4, 2016 at 16:23
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1$\begingroup$ @prakharlondhe: Yes, your Namu scale is a perfectly good absolute temperature scale. $\endgroup$ Commented Feb 4, 2016 at 16:26
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$\begingroup$ One more question, is There any bound that any new (absolute or not) temperature scale should be of form mK + c ? $\endgroup$ Commented Feb 4, 2016 at 16:30
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1$\begingroup$ The Kelvin scale is linear in the sense that for an ideal gas the internal energy is proportional to the temperature. So each extra degree K adds the same increment of internal energy. If you want your Namu scale $T_N$ to preserve this linearity then it needs to be related to the Kelvin scale $T_K$ by $T_N = aT_K + b$ where $a$ and $b$ are constants. I'm guessing this is what you mean by your expression mK + c. If you're not fussed about the linearity then you could use a more general scale, but all your equations will get more complicated if you do. $\endgroup$ Commented Feb 4, 2016 at 16:37
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1$\begingroup$ @prakharlondhe: correct - there is no restriction on the absolute temperature scale to be non linear $\endgroup$ Commented Feb 5, 2016 at 6:02