Celsius/Fahrenheit definition

16/12/2007 - 14:12 von Bernhard Kuemel | Report spam
Hi dsp!

Nachdem in sci.physics keiner geantwortet hat - sind wohl alle zu
sehr mit ihren virtual gravitons, hyperspheres, atheists usw.
beschaeftigt - probier ich's mal hier. Englisch versteht ihr eh,
nehm ich an, nachdem der Name der Gruppe englisch ist.


I just read at http://en.wikipedia.org/wiki/Celsius that the celsius
scale is currently defined via absolute zero = -237,15 C and the
triple point temperature of vienna standard mean ocean water (VSMOW)
(although Austria is landlocked :) = 0,1 C.

According to
http://en.wikipedia.org/wiki/Vienna...cean_Water this
puts the melting and boiling point of VSMOW at 101325 Pa to 0.000
089(10)°C and 99.9839°C.

That would mean bp-mp™.9838. AFAIK the K was designed to be equal
to 1 °C and we all know bp-mp initially was 100 C. So the K was made
too big and should have been smaller by a factor of 0.999838. Why
didn't they use 273.16/0.999839'3.20 instead of 273.16, which
would have made bp-mp closer to 100?

Who redefined the C?

http://en.wikipedia.org/wiki/Celsius , OTOH claims:

"However, current measurements show that the triple and melting
points of Vienna Standard Mean Ocean Water (VSMOW) are actually very
slightly (<0.001 °C) greater than 0.01 °C apart. Thus, the actual
melting point of ice is very slightly (less than a thousandth of a
degree) below 0 °C."

So, is mp(H2O) 0.000 089(10)°C or below 0 C?

http://en.wikipedia.org/wiki/Fahrenheit says: "TC = (TF − 32) ×
5/9". Did they redefine the F, too, or is this formula an approximation?

Thanks, Bernhard


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Lesen sie die antworten

#1 Jens Rodrigo
16/12/2007 - 22:27 | Warnen spam
Bernhard Kuemel schrieb:
http://en.wikipedia.org/wiki/Fahrenheit says: "TC = (TF ? 32) × 5/9".
Did they redefine the F, too, or is this formula an approximation?




°C = (°F - 32) / 1.8
http://www.sengpielaudio.com/calcul...enheit.htm
There was no redefinition of the fahrenheit scale.
The formula is exact.

Cheers Jens

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