Acidity: The Persistence of the Everyday in the Scientific

Acidity provides an interesting example of an everyday concept that developed fully into a scientific one; it is one of the oldest concepts in chemistry and remains an important one. However, up to now there has been no unity to it. Currently two standard theoretical definitions coexist (Brønsted and Lowry’s and Lewis’s); the standard laboratory measure of acidity, namely the pH, only corresponds directly to the Brønsted-Lowry concept. The lasting identity of the acidity concept in modern chemistry is based on the persistence of the quotidian concept. This is suggestive for considerations of other scientific concepts.