- #1
zenterix
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- TL;DR Summary
- Would it be possible to use as a thermometer a thermodynamic system consisting of a constant length wire by using the wire tension as the thermometric property?
I posted another question about a thermodynamic system with three coordinates, namely, that of a metallic wire. We can describe that system with temperature, wire tension, and wire length.
The result derived in that question was that the partial derivative of wire tension relative to absolute temperature (with length constant) is negative for a metallic wire (well, at least I think so, my question was precisely if this is the result obtained in the calculations I showed).
I also posted a question about thermometers and absolute temperature scales.
Can we use such a metallic wire as a thermometer, with the thermometric property being the tension?
Suppose the fixed length is L, and we determine the tension of the wire when the temperature is at the triple point of water. Call this tension ##\zeta_{TP}##.
Then, we change the temperature to some new equilibrium with a new tension. Now, at this point, I am using the word "temperature" without specifying if it is higher or lower than the initial state because we are in the process of defining the values of temperature.
Would we not have an empirical temperature scale defined by
##\theta(\zeta)=273.16\frac{\zeta}{\zeta_{TP}}##?
Now, this is still measured in Kelvin.
However, we would have, for example, the temperature at the boiling point of water being lower than the temperature at the freezing point.
Is this reasoning correct and would this temperature scale be considered "absolute"?
The result derived in that question was that the partial derivative of wire tension relative to absolute temperature (with length constant) is negative for a metallic wire (well, at least I think so, my question was precisely if this is the result obtained in the calculations I showed).
I also posted a question about thermometers and absolute temperature scales.
Can we use such a metallic wire as a thermometer, with the thermometric property being the tension?
Suppose the fixed length is L, and we determine the tension of the wire when the temperature is at the triple point of water. Call this tension ##\zeta_{TP}##.
Then, we change the temperature to some new equilibrium with a new tension. Now, at this point, I am using the word "temperature" without specifying if it is higher or lower than the initial state because we are in the process of defining the values of temperature.
Would we not have an empirical temperature scale defined by
##\theta(\zeta)=273.16\frac{\zeta}{\zeta_{TP}}##?
Now, this is still measured in Kelvin.
However, we would have, for example, the temperature at the boiling point of water being lower than the temperature at the freezing point.
Is this reasoning correct and would this temperature scale be considered "absolute"?