What kind of applications are there for the ph scale?

pH measurement is used in a wide variety of applications: agriculture, wastewater treatment, industrial processes, environmental monitoring, and in research and development. pH is a measure of the acidity or alkalinity of a solution. The pH value states the relative quantity of hydrogen ions (H+) contained in a solution. The greater the concentration of H+ the more acidic the solution and the lower the pH. In this relationship, pH is defined as the negative logarithm of hydrogen activity. A standard pH measuring system consists of three elements: 1) pH electrode; 2) temperature compensation element and 3) pH meter or controller.