TREVOR CLIFFORD PHOTOGRAPHY / SCIENCE PHOTO LIBRARY TREVOR CLIFFORD PHOTOGRAPHY / SCIENCE PHOTO LIBRARY
Close-up of the probe from a pH meter. A pH metre measures the concentration of hydrogen ions in an aqueous solution in order to determine its acidity or alkalinity. The probe is dipped into the solution being tested and the presence of hydrogen ions changes the electrical potential between a test electrode and standard electrode within the probe. This difference is directly related to the pH (negative log of the concentration of hydrogen ions).
Model release not required. Property release not required.