This test is done to determine the water content in soil by oven drying method as per IS: 2720 (Part II) – 1973. The water content (w) of a soil sample is equal to the mass of water divided by the mass of solids.
Apparatus required :-
i) Thermostatically controlled oven maintained at a temperature of 110 ± 5^oC
ii) Weighing balance, with an accuracy of 0.04% of the weight of the soil taken
iii) Air-tight container made of non-corrodible material with lid
iv) Tongs

PREPARATION OF SAMPLE
The soil specimen should be representative of the soil mass. The quantity of the specimen taken would depend upon the gradation and the maximum size of particles as under:

Procedure to determine Water Content In Soil By Oven Drying Method
i) Clean the container, dry it and weigh it with the lid (Weight ‘W₁‘).

ii) Take the required quantity of the wet soil specimen in the container and weigh it with the lid (Weight ‘W₂‘).

iii) Place the container, with its lid removed, in the oven till its weight becomes constant (Normally for 24hrs.).

iv) When the soil has dried, remove the container from the oven, using tongs.

v) Find the weight ‘W₃‘ of the container with the lid and the dry soil sample.

REPORTING OF RESULTS
The water content
w = [W₂-W₃] / [W₃ -W₁]*100%
An average of three determinations should be taken. A sample calculation is shown below