It's May 29, 2018 and the splash page for Google is displaying an homage to S.P.L. Sorensen who invented the pH scale.
Homage to pH
- Thread starter mabrungard
- Start date
Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:
I got them all right!
Tell them where he was working when he did it.
Do tell us!
OP
OP
Brewery
Nice, I will offer up a toast to him!
John
John
He was at the Carlsberg Laboratory founded by J. C. Jacobsen in 1875 to do research in the biological sciences, especially those related to brewing (he founded Carlsberg in 1847). The lab didn't actually become part of the brewery until 1972. Sørensen published the paper defining pH in 1909 whie he was director of the laboratory (1901 - 1938).
Last edited:
Anyone know what the "p" stands for in pH?
Yes
Oh - you probaly would like to know what it means, wouildn't you?
I'll start off by mentioning that that same question was asked in a lecture hall at the University of Louvaine during the DeClerck Chair XI gathering. I leapt to my feet and shouted out "Pundus Hydrogenii" (weight of hydrogen). That's not what it means. And it doesn't mean "potens" or "potenz" (power) either which is another popular misconception that you are likely to find if you look long enough. What it does mean is that in his paper Sørensen wanted convenient symbols for the concentration of H+ and OH- (actually any other ion - see No. 12) and chose p and q respectively. If he had any reason beyond needing a couple of letters he doesn't say what it is and I certainly don't know. So when I said I knew what it meant in No. 9 I was really fibbing. AFAIK it doesn't mean anything.
I'll start off by mentioning that that same question was asked in a lecture hall at the University of Louvaine during the DeClerck Chair XI gathering. I leapt to my feet and shouted out "Pundus Hydrogenii" (weight of hydrogen). That's not what it means. And it doesn't mean "potens" or "potenz" (power) either which is another popular misconception that you are likely to find if you look long enough. What it does mean is that in his paper Sørensen wanted convenient symbols for the concentration of H+ and OH- (actually any other ion - see No. 12) and chose p and q respectively. If he had any reason beyond needing a couple of letters he doesn't say what it is and I certainly don't know. So when I said I knew what it meant in No. 9 I was really fibbing. AFAIK it doesn't mean anything.
Last edited:
I don't know is the right answer. There's no record of its meaning, anyway. Like you said, it's likely just a random variable that made it into the nomenclature.
Like Harry S Truman's middle name.
Like Harry S Truman's middle name.
I think we have to credit Sørensen with putting it into the nomenclature.
Enzyme Studies
Part II
On the Measurement and Significance of Hydrogen Ion Concentration in Enzymatic Processes
S. P. L. Sørenson Carlsberg Laboratory, Copenhagen Submitted 29 May 1909
A. Electometric Measurement
b) Determination of π(sub p) (page 25) π(sub p) means π subscripted with the letter p)
If one denotes by π(sub p) the electromotive force of an element produced by a mercury-calomel electrode in an 0.1 N potassium chloride solution and a platinum-hydrogen electrode the resulting hydrogen ion concentration (with a 1 N solution of hydrogen ions as a reference) of that is C(sub p) = 10(super -p) and if one denotes by π(sub q) and C(sub q) = 10(super q) the magnitude of another similar element....
That's what he wrote (more or less - no guarantee that the translation is 100%) and it's pretty clear to me that it was on page 25 that pH was defined as he wrote the hydrogen ion concentration as 10^-p and we write it as 10^-pH. But I can't attach any more significance to his choice of p and q than I do when I write, for example, "Let p be the probability of heads and q the probability of tails"
Enzyme Studies
Part II
On the Measurement and Significance of Hydrogen Ion Concentration in Enzymatic Processes
S. P. L. Sørenson Carlsberg Laboratory, Copenhagen Submitted 29 May 1909
A. Electometric Measurement
b) Determination of π(sub p) (page 25) π(sub p) means π subscripted with the letter p)
If one denotes by π(sub p) the electromotive force of an element produced by a mercury-calomel electrode in an 0.1 N potassium chloride solution and a platinum-hydrogen electrode the resulting hydrogen ion concentration (with a 1 N solution of hydrogen ions as a reference) of that is C(sub p) = 10(super -p) and if one denotes by π(sub q) and C(sub q) = 10(super q) the magnitude of another similar element....
That's what he wrote (more or less - no guarantee that the translation is 100%) and it's pretty clear to me that it was on page 25 that pH was defined as he wrote the hydrogen ion concentration as 10^-p and we write it as 10^-pH. But I can't attach any more significance to his choice of p and q than I do when I write, for example, "Let p be the probability of heads and q the probability of tails"
Last edited:
Similar threads
