Conductivity describes the ability of a solution to conduct an electric current. There are a few methods for measuring the conductivity of a solution, and the most straightforward to understand is probably the amperometric method. This method simply applies a voltage between two electrodes and measures the current. While this method is simple to describe, it can have complications in practice and it isn’t always the most accurate method. Another way of measuring conductivity is with a potentiometric method, which makes use of two pairs of rings. There are two outer rings that apply an alternating voltage, and this results in a loop of current being generated in the solution. The other pair of rings sits inside the first and measures the change in voltage between the pairs of rings; this change in voltage is directly related to the magnitude of the current loop induced by the outer rings, which is in turn directly related to the conductivity of the solution. Other methods exist to measure conductivity, but these are probably the easiest to both describe and understand.