Which statement is not true regarding specific gravity?

Concept:

Specific Gravity:

Specific gravity can be defined as the ratio of the weight of a given volume of soil solids at a given temperature to the weight of the equal volume of distilled water at that temperature. It can be written as G = \(\dfrac{\gamma_s}{\gamma_w}\)

1. Density bottle method:

• The specific gravity of solid particles can be determined in a laboratory using a density bottle fitted with a stopper having a hole.
• The density bottle of 50 ml capacity is generally used [ IS:2720 (part III) 1980].

2. Pycnometer method:

• Pycnometer method is used to determine specific gravity and water content both.
• This method is suitable for cohesionless soils.
• A pycnometer is a glass jar of 1-liter capacity that is fitted at its top by a conical cap made of brass.
• It has a screw-type cover and there is a small hole at its apex of 6 mm in diameter

Explanation:

• Density bottle method can be used for every type of soil, and it is the most accurate one.
• Flask and pycnometer are used for coarse-grained soil.
• Distilled water is used in the pycnometer test and kerosene is used for the density bottle method. When kerosene is used, its specific gravity is determined accurately by a separate test.