What is the capacity of density bottle used generally for determination of specific gravity of fine-grained soil in the laboratory as per IS 2720 (Part 3/sec-1)-1980?
Try it first: pick an option, then read the explanation.
Correct answer: C. 50 ml
Detailed Explanation
Specific gravity of fine-grained soil (silt and clay) is determined in the laboratory using a small-volume density bottle (also called a specific gravity bottle), because fine particles need a narrow, tall vessel with a well-fitted stopper to allow trapped air to be removed reliably and to measure volume/weight differences precisely at a small scale. As per IS 2720 (Part 3/Section 1)-1980, the density bottle used for this purpose has a capacity of 50 ml.
For coarser soils (sand-sized particles and larger), a bigger vessel such as a pycnometer (about 900 ml) is used instead, since fine bottles would be impractical to fill and de-air with larger, heavier particles.
Key Concepts for Students
- Density bottle (specific gravity bottle): 50 ml capacity, used for fine-grained soils (silt/clay).
- Pycnometer: much larger (about 900 ml), used for coarser (sand-sized) soils where a small bottle would be impractical.
- The general method for both devices is the same principle: comparing the weight of a known volume of soil-water mixture against the weight of water alone, using the bottle's calibrated volume.
- Careful removal of entrapped air (often by applying vacuum or gentle boiling) is essential for accurate specific gravity results with either device.