The rod method is a method for measuring the surface tension of a liquid and the interfacial tension between two liquids with a force sensor tensiometer.
The rod method is based on the Wilhelmy plate method, a cylindrical rod being used instead of a plate. This allows measurements to be carried out in smaller vessels, which would lead to disruptive edge effects if using the larger plate. The advantage therefore lies in smaller sample volumes. The disadvantage is a smaller wetted length (equal to the circumference of the rod), which is associated with a smaller resulting force and therefore a lower measurement resolution.