How does hydrometer method determine soil texture?

How does hydrometer method determine soil texture?

The hydrometer method of particle size analysis calculates the physical proportions of these soil particles based on their settling rates in an aqueous solution and identifies three size classes: sand (2000 – 50 µm), silt (50 – 2.0 µm) and clay < 2.0 µm.

How do you use a soil hydrometer?

4.3 Sedimentation test with hydrometer

1. Insert a rubber ball or any other suitable cover on the top of the 1000 ml measuring cylinder containing the soil suspension and shake it vigorously end over end.
2. Immerse the hydrometer gently to a depth slightly below its floating position and then allow it to float freely.

How do you perform a hydrometer test?

Fill a 1000-cc graduate with water to approximately 700 cc. Observe and record the reading of the water level. Insert the hydrometer and again observe and record the reading. The difference in these two readings equals the volume of the bulb plus the part of the stem that is submerged.

Does hydrometer analysis determine the size of soil particles exactly?

Hydrometer test is carried out to quantitatively determine the Particle/Grain Size Distribution for soil particles of size smaller than 75 micron. Calibrated at 27°C, range of 0.995 to 1.030 g/cc, graduation lines at interval of 0.0005; in conformity with IS-3104: 1965.

How do you calculate hydrometer?

Insert the hydrometer in the measuring cylinder containing about 700 ml of water. Take the readings of the hydrometer at the top and bottom of the meniscus. The difference between two readings is taken as meniscus correction (Cm) which is a constant for a hydrometer.

How do you measure soil particle size?

The sieve-pipette is the standard method for determining soil particle size distribution (PSD) because it is precise and reproducible.

How is the hydrometer used in soil analysis?

The hydrometer analysis is a widely used method of obtaining an estimate of the distribution of soil particle sizes from the #200 (0.075 mm) sieve to around 0.001 mm. The data are plotted on a semi-log plot of percent finer versus grain diameters to represent the particle size distribution.

Why do you need a hydrometer for sieve analysis?

Both sieve analysis and hydrometer analysis are required to obtain the complete gradation curve of the coarse and fine fraction of many natural soils. Hydrometer analysis is essential for obtaining the complete particle size distribution of such soils.

What should be included in a hydrometer report?

Your report should include the following: Analysis of the test results – Complete the table provided and show one sample calculation. Draw the grain size distribution curve for the data from the hydrometer analysis only and the combined grain-size distribution curve.

What kind of dispersing agent is used in hydrometer analysis?

Dispersing agent [sodium hexametaphosphate (NaPO 3) or sodium silicate (NaSiO 3 )] ASTM D7928: Standard Test Method for Particle-Size Distribution (Gradation) of Fine-Grained Soils Using the Sedimentation (Hydrometer) Analysis