Viscosity Measurement Technique Using Standard Glass Burette for Newtonian Liquids

A simple and inexpensive technique for measurement of kinematic viscosity of Newtonian liquids, based on the discharge time of liquid through a standard glass burette, was developed and calibrated with the standard Redwood viscometer measurements. Vegetable oils such as sunflower, palm, groundnut, and coconut, along with distilled water, were studied at temperatures from 30 to 90°C. Non‐linear calibration equations, y = A + Bx + C/x + D/x 2 (R2 = 0.9856) and y = A + Bx + C/x (R2 ≥ 0.9376), expressing kinematic viscosity in terms of non‐dimensional time from burette discharge times, gave good predictions of the five types of equations considered. Specific equations were required for each liquid and an overall equation combining all oil data was not satisfactory (R2 ≤ 0.6377). A theoretical equation, developed based on Hagen‐Poiseuille's law, gave very good performance (R2 ≥ 0.9715) with all the oils studied. The proposed method of viscosity measurement, as an alternative usage of a burette, has the potential of developing a new instrument for measurement of viscosity.