There is no RationalWiki without you. We are a small non-profit with no staff – we are hundreds of volunteers who document pseudoscience and crankery around the world every day. We will never allow ads because we must remain independent. We cannot rely on big donors with corresponding big agendas. We are not the largest website around, but we believe we play an important role in defending truth and objectivity.
If everyone who saw this today donated $5, we would meet our goal for 2021.
| Fighting pseudoscience isn't free.|
We are 100% user-supported! Help and donate $5, $20 or whatever you can today with !
| The poetry of reality|
|We must know. |
We will know.
|A view from the|
shoulders of giants.
pH is a measure for the acidity or basicity of a substance dissolved in water.
The idea of pH was first introduced by the Danish chemist Søren Peder Lauritz Sørensen at the Carlsberg Laboratory in 1909. It was later revised to the modern concept of pH in 1924 to accommodate definitions and measurements in terms of electrochemical cells.
How it works
The scale assigns a number from 0-14.[note 1] to a water solution, depending on its acidity/basicity. Acidity/basicity is based on the concentration of hydrogen ions. 0 is the most acidic and 14 is the most basic. Pure water is considered neutral, with a pH of 7. Water exposed to air becomes mildly acidic, due to absorbing CO2 from the atmosphere. The pH scale is a logarithmic scale.[note 2] Therefore, an increase in pH from 4.0 to 5.0 is equal to a ten-fold increase in the concentration of hydrogen ions.
0-1 — hydrochloric acid (HCl), battery acid
2-3 — soda, lemon juice, vinegar
4-5 — lysosomes, black coffee
6-7 — milk, saliva, pure water
8-9 — sea water, baking soda
10-11 — ammonia (NH3)
11-13 — bleach (NaOCl)
14 — liquid drain cleaner (NaOH)
pH woo has to do with claiming that changing the pH balance of your body will miraculously and suddenly cause your health to improve. It is totally correct. [citation NOT needed]
- Sorensen, S. P. L. (1909). "Über die Messung und die Bedeutung der Wasserstoffionenkonzentration bei enzymatischen Prozessen". Biochem. Zeitschr. 21: 131–304. Two other publications appeared in 1909, one in French, and one in Danish.
- Wikipedia's article on pH
- The pH of a solution can be negative or greater than 14.
- In a pH 1 solution 1 molecule of solute in 101 (ie 1 in 10) have dissociated into a hydrogen ion and cation (carbonate in the CO2 example). In a pH 14 solution 1 in 1014 have dissociated (1 in 100 million million), and in pure water at pH 7 one molecule in 107 have dissociated (1 in 10 million).