Electrical conductivity: a useful technique in teaching geomorphology

Abstract

The electrical conductivity of a water sample is proportional to its total dissolved solids content. Since conductivity can be measured easily and quickly by commercially available meters it is admirably suited to geomorphological field work on the dissolved solids content of natural waters. The technique lends itself to exercises involving work in the field, the classroom and the laboratory and it therefore allows integration of these three approaches to geomorphology teaching.

The conductivity of a given sample varies with temperature and is heavily influenced by hydrogen ions when the pH is below about 5.5. This paper describes the methods used to correct for these effects, and the procedure for constructing calibration curves of conductivity and total dissolved solids. It gives the characteristics of commonly available field instruments, and some guidelines for choosing an instrument. Some exercises involving conductivity are outlined.