Group image of 250ml, 500ml, and (unnamed) stoppered flasks. A minimum capacity of 250ml is specified, and a 500ml capacity flask is sometimes required. The stopper physically controls the water volume of stoppered flasks. Volumetric flasks are typically used but require careful adjustment of water to the calibration mark. Pycnometers: the test method permits the use of a volumetric flask or iodine flasks with a stopper.Table Resource: Specific Gravity Lab Equipment and Apparatus This blog post will focus on the equipment and procedures used to perform the ASTM/AASHTO method. Reliable test results depend on strict adherence to the practices and techniques outlined.
Practitioners should be aware of the significant differences between the test methods. While the equipment required is not sophisticated, the procedures are extensive and meticulous, and performing the test by the book can be a challenge. As with any laboratory test, these methods require attention to detail but are easy to perform correctly and do not require much in the way of specialized techniques or equipment.ĪSTM D854, and the identical AASHTO T 100, Standard Test Methods for Specific Gravity of Soil Solids by Water Pycnometer, focus on producing measurements with a high degree of precision. Army Corps of Engineers laboratory soils testing manual, and some state DOTs are often considered adequate for basic applications. Standard test methods described in the U.S. Traditional methods for determining specific gravity are straightforward. Applications include the foundation design for structures, calculations for the stability of soil embankments, and estimations of settlement for engineered soil fills. This dimensionless unit is the ratio of material density to the density of water and is used to calculate soil density, void ratio, saturation, and other soil properties. Specific gravity is a fundamental property of soils and other construction materials. See also Measure liquids density: hydrometer.Importance of Specific Gravity of Soil Solids You could glue a strip of card with a marked scale on it inside the test tube against which to measure the depth at which the tube floats. However, because the test tube is much narrower than the beaker, the depth of the test tube varies much more than the level in the beaker. This is also equal to the volume of liquid displaced. The drawback of this method is that the beaker is quite wide so the rise in the liquid level in the beaker could be quite small and difficult to measure accurately.Ī better method, as used in the hyrdometer, is to compare the volume of the test tube which is below the liquid surface. Comparing the change in height for the liquids of unknown density with that for water will give you the relative density of the liquid. The only quantities which change are the density of liquid and the rise in its level in the beaker. According to Archimedes' Principle, if the test tube floats then the weight of the liquid displaced equals the weight of the test tube, which is constant. (Mercury is toxic so the vial should not be opened except with laboratory precautions.) Put the various liquids into the beaker one at a time, put the test tube containing the vial of mercury in the liquid, and measure the rise in the level of liquid in the beaker. You would put the vial of mercury into the test tube to act as ballast.
Your suggestion would work but it would not be accurate.
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