Archimedes Revisited: A Faster, Better, Cheaper Method of Accurately Measuring the Volume of Small Objects

A little-known method of measuring the volume of small objects based on Archimedes principle is described, which involves suspending an object in a water-filled container placed on electronic scales. The suspension technique is a variation on the hydrostatic weighing technique used for measuring volume. The suspension method was compared with two other traditional water displacement methods of measuring volume – i.e. placing an object in a measuring cylinder and recording the rise in the water level and immersing the object in a water-filled container with an overflow spout to record the volume of overflow. The accuracy and precision of the three methods was compared using 10 accurately machined PVC cylinders ranging in volume from 1.5 to 15.7 ml. The mean difference between the actual and measured volumes was 3.3 +/- 7.3%, -1.6 +/- 7.2% and 0.03 +/- 0.45%, for the level, overflow and suspension methods respectively. Each measurement was repeated twice to obtain the reproducibility of the three displacement techniques. The reproducibility was –1.7 +/- 8.5%, 0.09 +/- 3% and –0.04 +/- 0.43% for the level, overflow and suspension techniques respectively. The results show that the suspension technique is more accurate and precise than the traditional water displacement methods and is more accurate than measuring volume using Vernier calliper measurements.