Similar term(s): acidity, alkalinity.
pH is a measure of the concentration of
protons (H+) in a solution and, therefore, its
acidity or alkalinity. The concept was
introduced by S.P.L. Sørensen in 1909. The p stands for the German "Potenz",
meaning power or concentration, and the H
for the hydrogen ion (H+). In
layman's terms , the "pH" value is an approximate number between 0 and 14 that
indicates whether a solution is acidic (pH < 7), basic (pH > 7) or
neither (pH = 7) [neutral].
Acids taste sour and react strongly with metals. Strong acids
can burn your skin. Examples of acids include vinegar, citrus fruits and stomach
Bases taste bitter and feel slippery. Strong bases can burn
your skin. Examples of bases include lye (sodium hydroxide used to make soap)
When acids and bases are added to each other, they react to neutralize each
other, forming salt and water.
Source: GreenFacts, based on: Technology Studies in Education
Bases and pH Scale