Torr and mmHg ??

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rprosperi
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Re: Torr and mmHg ??

Post by rprosperi » Mon Jun 22, 2020 10:24 pm

Walter wrote:
Mon Jun 22, 2020 10:18 pm
Yeah, yeah, you-know-who again ... :roll:
Not again... it's you-know-who still... even after all these years... sigh... I hardly ever even hear talk about it here anymore... it's sad... :oops:
--bob p

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Jaymos
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Re: Torr and mmHg ??

Post by Jaymos » Mon Jun 22, 2020 11:21 pm

Walter wrote:
Mon Jun 22, 2020 10:18 pm
..,
Back to topic: For WolframAlpha, Torr and mmHg are identical.
I fixed both mm.Hg ≠ Torr (and in.Hg ≠ 25.4 Torr) to the correct non-NIST constants in 43C.

NIST and WA does not convince ;-). BS and NPL do. I think WA and WikiDE and WikiFR ignore the facts. And NIST throws away the digits saying compressibility of mercury is varying. But at the same time they also don't chop off c's digits because of uncertainty to the medium - they expect you to consider that.

😂If you are still unsure maybe put the mmHg definition in your regional shortcut settings ;-) and add some logic for determining which countries use settings MULT⋅ and MULT×, and while you are at it, change the gap separator also to an optional "," to automatically default to that of the radix setting, also regional of course :lol:
Jaco Mostert
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grsbanks
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Re: Torr and mmHg ??

Post by grsbanks » Tue Jun 23, 2020 6:26 am

rprosperi wrote:
Mon Jun 22, 2020 10:24 pm
Not again... it's you-know-who still... even after all these years... sigh... I hardly ever even hear talk about it here anymore... it's sad... :oops:
You know, some people will use anything as long as it's not the metric system...

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Walter
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Re: Torr and mmHg ??

Post by Walter » Tue Jun 23, 2020 6:38 am

grsbanks wrote:
Tue Jun 23, 2020 6:26 am
rprosperi wrote:
Mon Jun 22, 2020 10:24 pm
Not again... it's you-know-who still... even after all these years... sigh... I hardly ever even hear talk about it here anymore... it's sad... :oops:
You know, some people will use anything as long as it's not the metric system...
:lol: Problem: What is one Midwestern cow divided by three Imperial British thumbs? :?
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PierreMengisen
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Re: Torr and mmHg ??

Post by PierreMengisen » Tue Jun 23, 2020 7:32 am

Walter wrote:
Tue Jun 23, 2020 6:38 am
Problem: What is one Midwestern cow divided by three Imperial British thumbs?
A number of excellent barbecues ? :cry: :cry: :cry:
Pierre
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Walter
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Re: Torr and mmHg ??

Post by Walter » Tue Jun 23, 2020 10:07 am

Jaymos wrote:
Mon Jun 22, 2020 11:21 pm
... NIST throws away the digits saying compressibility of mercury is varying. But at the same time they also don't chop off c's digits because of uncertainty to the medium ...
Not sure I got your point. What c are you talking about? :?
The c I know is speed of light in vacuum - no medium per definition. Thanks in advance for enlightenment (pun intended). 8-)
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Jaymos
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Re: Torr and mmHg ??

Post by Jaymos » Tue Jun 23, 2020 10:17 am

Walter wrote:
Tue Jun 23, 2020 10:07 am
Jaymos wrote:
Mon Jun 22, 2020 11:21 pm
... NIST throws away the digits saying compressibility of mercury is varying. But at the same time they also don't chop off c's digits because of uncertainty to the medium ...
Not sure I got your point. What c are you talking about? :?
The c I know is speed of light in vacuum - no medium per definition. Thanks in advance for enlightenment (pun intended). 8-)
If my example is insufficient for your understanding, pick another example or just think about the original point. I think I said enough about mmHg, ending it with why I changed mine myself.
Jaco Mostert
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Walter
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Re: Torr and mmHg ??

Post by Walter » Tue Jun 23, 2020 10:28 am

Jaymos wrote:
Tue Jun 23, 2020 10:17 am
Walter wrote:
Tue Jun 23, 2020 10:07 am
Jaymos wrote:
Mon Jun 22, 2020 11:21 pm
... NIST throws away the digits saying compressibility of mercury is varying. But at the same time they also don't chop off c's digits because of uncertainty to the medium ...
Not sure I got your point. What c are you talking about? :?
The c I know is speed of light in vacuum - no medium per definition. Thanks in advance for enlightenment (pun intended). 8-)
If my example is insufficient for your understanding, pick another example or just think about the original point. I think I said enough about mmHg, ending it with why I changed mine myself.
Thanks. Seems you're unable or unwilling to explain it. That isn't an advantage for your intention though.
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Walter
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Re: Torr and mmHg ??

Post by Walter » Tue Jun 23, 2020 7:51 pm

Results of a little open internet search with some numbers:
  1. 133.322 returns 162000 hits. This is the most precise value valid for both conversions.
  2. 133.3224 returns 7600 hits. This is the most precise rounded value valid for both conversions and the most precise NIST states for mmHg.
  3. 133.322368 returns 2220 hits. This is valid for Torr only.
  4. 133.3223684 returns 1880 hits. This is valid for Torr only.
  5. 133.322387 returns 44 hits. This is valid for "conventional" mmHg only.
  6. 133.3223874 returns 29 hits. This is valid for "conventional" mmHg only.
The vast majority of these pressure conversions work with 3 or 4 decimals only, being equal for both units. Of those who specify more digits, 98% use them for Torr. This supports what NIST states in its publication of 2008.
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ijabbott
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Re: Torr and mmHg ??

Post by ijabbott » Wed Jun 24, 2020 9:55 pm

Walter wrote:
Tue Jun 23, 2020 10:07 am
Jaymos wrote:
Mon Jun 22, 2020 11:21 pm
... NIST throws away the digits saying compressibility of mercury is varying. But at the same time they also don't chop off c's digits because of uncertainty to the medium ...
Not sure I got your point. What c are you talking about? :?
The c I know is speed of light in vacuum - no medium per definition. Thanks in advance for enlightenment (pun intended). 8-)
And c is now fixed to an exact value by definition of the SI base units, so there is no longer any room for uncertainty.

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