The pH scale that is widely accepted and used by scientists didn't actually exist until 1909. Before then scientists had to rely on using adjectives to describe the acidity or basicity of a substance ...

However, water comes from different sources, like tap water or river water. These water samples have other substances dissolved in them. They might show up as slightly acidic or slightly alkaline ...

Today on Google's home page is a fun interactive pH scale, a scale for measuring acidity and alkalinity, remembering S.P.L. Sørensen. He was a Danish chemist born on January 9, 1868 in Havrebjerg, ...