This test is done to determine the water content in soil by calcium carbide
method as per IS: 2720 (Part II) – 1973. It is a method for rapid
determination of water content from the gas pressure developed by the
reaction of calcium carbide with the free water of the soil. From the
calibrated scale of the pressure gauge the percentage of water on total
mass of wet soil is obtained and the same is converted to water content
on dry mass of soil.