The Pycnometer is used for determination of specific gravity of soil particles of both fine grained and coarse grained soils. The determinination of specific gravity of soil will help in the calculation of void ratio, degree of saturation and other different soil properties.

This is a glass jar of 1 litre capacity that is fitted at its top by a conical cap made of brass. It has a screw type cover as shown.

There is a small hole at its apex of 6mm diameter. The leakage is prevented by having a washer between the cap and the jar. While closing the jar, it is screwed till the mark so that the volume of the pycnometer will remain constant throughout the calculation.