How to Measure Conductivity in Water Salinity

A multimeter is useful in determining conductivity.

Conductivity is the measure of how easily electrons are able to transfer through a media. Water is generally a poor conductor of electrons. However, when salts and other ions are dissolved in water, the overall conductivity is increased as the electrons can follow paths between the ions. High conductivity indicates low electronic resistance. By measuring resistance (denoted by Ohms), one can inversely measure conductivity. Pure water (distilled) typically reads at about 18 mega-ohms of resistance, which is very little conductivity.

Things You'll Need

• Multimeter

Instructions

1. Turn on the multimeter and position the measurement indicator for ohms. Ohms are typically signified by the Greek letter "omega."

2. Insert the two probes of the multimeter into the saline water at two different ends of the container.

3. Read the results on the multimeter. The lower the resistance, or number of ohms, the higher the conductivity. Even water with high concentrations of salt will still have limited conductivity compared to metals.

References

• Horiba: Ions in Water, and Conductivity