pH Scale

The pH scale is a logarithmic measure of the concentration of hydrogen ions. It is used to measure the acidity or basicity of a substance. It has a range of 1 to 14, with one being the most acidic and fourteen being the most basic. pH paper uses colors to identify the pH of solutions.

History of the pH Scale

Soren Peter Lauritz Sorenson in 1909 defined pH as a logarithmic measure of hydrogen ion concentration.

Application of the pH Scale

The pH scale is good for measuring the acidity or how basic a solution is. The pH scale is mainly used in scientific experiments. It is also useful when trying to neutralize a solution. Knowing the rating of a solution will help you to stay away from harmful substances. For example, if using an exfoliant for your face you would not want to use one with a pH of 2, but of 6. 6 is closer to neutral, which means that it is a weak acid and will not case much harm or discomfort.


  1. Beiser, A. (1988). Physical Science (2nd Edition). New York, NY: McGraw Hill
  2. //
external image placeholder?w=200&h=50

This WikiPage developed by (Charita Miller - 2011SU)