I. Pycnometer/Volumetric Flask Calibration

1. Clean and dry the pycnometer.

2. Fill the bottle with distilled water up to the meniscus of the calibration mark of the bottle.

3. Dry the outside of the bottle and the inside of the neck above the calibration mark.

4. Weigh the bottle with water to 0.01 grams.

5. Read and record the water temperature to 0.01°C, with the thermometer inserted to a fixed depth.

6. Heat the bottle with water slightly in a water bath. Repeat steps 3 to 5 each time removing enough water to bring the meniscus down to the calibration mark. The temperature must be in a range between 20°C to 40°C.

7. Draw the calibration curve by plotting temperature against weight.

II. Determination of Specific Gravity

The sample may be tested at its natural water content or be oven dried. Its weigh on an oven – dry basis shall be at least 25 grams. Clay samples shall be dispersed in distilled water before testing with the use of special dispersing apparatus. If the soil is cohesive, it shall be soaked in distilled water for at least 12 hours.

1. Transfer carefully the sample to the calibrated bottle and add distilled water until about ½ full. Avoid loss of soil during the transfer.

2. Remove entrapped air by boiling gently for at least 10 minutes. Roll occasionally the bottle to assist in the removal of air.

3. Cool the bottle within range of the calibration curve of the bottle.

4. Fill the bottle with distilled water to bring the bottom of the meniscus to the calibration mark.

5. Dry the outside of the bottle.

6. Weigh the bottle with water and soil to 0.01 grams.

7. Record the temperature of the contents to 0.1°C.