What is the true value of the water triple point temperature?

In summary, there seems to be some discrepancy regarding the exact value of the water triple point temperature. While some sources state it as 272.16K, others report it as 273.15K. It is possible that the latter value is a result of historical definitions and slight changes in the Celsius and Kelvin scales. Further research is needed to determine the source of the value 273.1598K.
  • #1
Diego Saravia
1
0
Water triple point T is 272.16K

http://www.omega.com/temperature/z/pdf/z186-193.pdf
http://media4.physics.indiana.edu/~courses/p340/S11/Lecture_Presentations/ITS-90_metrologia.pdf


But several internet pages say that water triple point is at 273.1598 K
http://www.quimica.es/enciclopedia/Punto_triple.html
http://temperaturemeasurement.wordpress.com/2010/07/08/international-temperature-scale/http://www.duncaninstr.com/pdfs/Temperature%20Measurement.pdf
http://es.scribd.com/doc/61755350/Punto-Triple-y-Punto-Critico

Which is the source of this number 273.1598?
 
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  • #2
Perhaps a historical artifact? Original definition of deg C used melting and boiling temperatures of water, perhaps 273.1598 is a triple point measured using these old degrees. In 1954, after Kelvin was defined as exactly ##\frac 1 {273.16}## both Celsius and Kelvin slightly changed. But I am just guessing.
 
  • #3
they are so closed numbers not to to much go through that :D
 
  • #4
The first site you reference states
La única combinación de presión y temperatura a la que el agua, hielo y vapor de agua pueden coexistir en un equilibrio estable se produce exactamente a una temperatura de 273.1598 K (0.0098 ° C) y a una presión parcial de vapor de agua de 611,73 pascales (6,1173 milibares, 0,0060373057 atm).
which I take that the one temperature is exact.

I think Borus is correct. The defining of the Kelvin scale left the Celcius scale to be redefined as the triple and boiling point of water and that was "assumed" to be 273.16 K. Experimentation afterwards found the actual triple point was not 0.01 C and therin lies the descrepancy.
 
  • #5
Diego Saravia said:
Water triple point T is 272.16K

http://www.omega.com/temperature/z/pdf/z186-193.pdf
http://media4.physics.indiana.edu/~courses/p340/S11/Lecture_Presentations/ITS-90_metrologia.pdf


But several internet pages say that water triple point is at 273.1598 K
http://www.quimica.es/enciclopedia/Punto_triple.html
http://temperaturemeasurement.wordpress.com/2010/07/08/international-temperature-scale/http://www.duncaninstr.com/pdfs/Temperature%20Measurement.pdf
http://es.scribd.com/doc/61755350/Punto-Triple-y-Punto-Critico

Which is the source of this number 273.1598?

It seems that the question is "what is the source of the 272.16 value" that you show here.
I looked at the first link indicated in the post. I did not read it all, it's a long pdf. However it refers several times to the triple point temperature as 273.15..
The second link does not work for me.

It is somehow interesting that the triple point of the ionic liquid 1-Methylimidazole is reported as 272.16. Is it possible that you confused some values?
The link is here:
http://www.chemie1.uni-rostock.de/pci/emelyanenko/publications/62.pdf

For water it is about 273.16K
http://physics.nist.gov/cuu/Units/kelvin.html
 
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1. What is the water triple point?

The water triple point is the unique combination of temperature and pressure at which water exists in all three phases (solid, liquid, and gas) in equilibrium.

2. What is the temperature of the water triple point?

The temperature of the water triple point is 273.1598 Kelvin or 0.01 degrees Celsius. This is the temperature at which ice, liquid water, and water vapor can exist simultaneously.

3. What is the pressure at the water triple point?

The pressure at the water triple point is 611.73 Pa (pascals) or 0.0060373 atm (atmospheres). This is the pressure required to maintain the equilibrium between the three phases of water at the temperature of 273.1598 K.

4. Why is the water triple point important?

The water triple point is important because it is a fundamental concept in thermodynamics and the study of phase changes. It is also a defining point for the Kelvin temperature scale and is used as a standard reference point for temperature measurements.

5. Can the water triple point be observed in nature?

It is possible to observe the water triple point in nature, but it is very rare. The conditions required for the triple point to occur are not commonly found in the Earth's atmosphere. However, it can be artificially created in laboratory settings to study the behavior of water at this unique point.

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