Talk:Parts-per notation

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All of the information here is equally applicable to ppt, ppb, ppq etc and to some extent duplicates what is included in the concentration article. I therefore propose we move some of the content from the concentration page here and redirect to this from all uses of ppt etc. The articles are currently a bit of a mess with duplicate stubs, a redirect to the concentration and complete lack of consistency.

Just to summarise what pages I think should be redirected here:

This has been changed to a disambiguation page. PAR 15:44, 1 January 2006 (UTC)

--NHSavage 08:38, 14 August 2005 (UTC)

Yes, the mentioned pp- stubs should be redirected to a parts per notation page with a good explanation. Duplication of the relevant material in concentration rather than a move of that info would be in order. Vsmith 13:58, 14 August 2005 (UTC)
This article has been renamed after the result of a move request. Please now continue with the cleanup. violet/riga (t) 13:48, 21 August 2005 (UTC)
Cleanup done. I think that this article still needs some work to further explain the differences between part per by volume, mass etc. I will think some more about this and also link to this from the concentration article. --NHSavage 20:47, 26 August 2005 (UTC)

Contents

[edit] 2003-2004 discussion

"The ppm value is equivalent to the absolute fractional amount multiplied by one million." This needs to be expanded. For those who actually need this article, this will be more confusing than the words "parts per million."

An example would help (I mean, an example like "a drop of blood in a 50 gallon drum would be about n parts per million"). --Larry Sanger


Is the exact calculation/definition:

ppm = solute / solvent * 1000000 ?

or

ppm = solute / total solution * 1000000 ?

or could be both ? like we use percentage, sometimes it needs to specify which two we are comparing ?

also, is it must be the same units ? like mass over mass,

or it could be mass over volume, without specifying other variables like temperature ?

[edit] Examples

The examples don't seem to be too accurate. A drop is usually defined as 0.05 ml, which then gives;

1 drop in 50 ml = 1‰, 50ml is a very small cup
1 drop in 50 l = 1ppm 50 l is about 11 gallons, not 40
1 drop in 50 cubic metres = 1 ppb
1 drop in 50,000 cubic metres = 1ppt, a 50 m swimming pool is 50*25*2 = 2,500 m^3
1 drop in 50,000,000 cubic metres = 1ppq, 50,000,000 m^3 is equivalent to a lake covering a square kilometre, and 50 metres deep, which is more than "medium sized" IMHO --Tom k&e 11:23, 6 September 2005 (UTC)

[edit] Other uses

PPM is also used to describe the accuracy of precision equipment such as a voltage calibrator. For example, see http://www.valhallascientific.com/calibrators/cal-2701c.shtml . 68.11.218.237 23:53, 19 April 2006 (UTC)

Thank you for this, I have added it in to the article.--NHSavage 06:50, 20 April 2006 (UTC)

[edit] absolutely confusing

Do you mean “parts per” notation, perhaps? Jclerman 15:35, 24 June 2006 (UTC)


[edit] Notes

The notes need to be totally redone. 3 does not refer to anything about it, and there is no 4. --Storkk 01:20, 20 August 2006 (UTC)

[edit] What the...

Well thsi article stinks. Its bloody confusing. If parts per hundred is the same as 100% stuff, then that means number of molecules per hundred total, not per every other 99. So 1pph is 1 molecule per 100 total molecules.

Just say that!Tourskin 03:41, 12 February 2007 (UTC)

[edit] WRONG, VERY VERY WRONG MY FRIENDS!

This article is complete crap - sorry for the terminology, but if my old chemistyr teacher was here to see this awful article... Parts per million is NOT involving particles. It involves mass. So for NaCl which could be 5ppm in water, thats 5 gramms of NaCl per 1,000,000 gramms of water. Tourskin 06:27, 14 February 2007 (UTC)

I don't see why you're so upset. Parts per million could just as easily be used to denote the number of particles as well as the number of grams. That's why its Parts per million and not any single unit.67.150.213.150 07:17, 4 March 2007 (UTC)

[edit] Mentioning very few parts-per notations

Should we include examples for "very few parts-per notations" like homeopathy or large scale relations as in Orders of magnitude (numbers) or the Avogadro constant?

Homeopathy goes up to dilutions of one part per 1060 and even 10150, which are beyond Planck Scales in relation to the visible universe and therefore only imaginary. Ollj 23:08, 12 March 2007 (UTC)

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