1. Take about 20 g of soil sample, passing 425 micron IS sieve. Mix it on the glass plate with sufficient distilled water to make it plastic enough to be shaped into a ball. Allow the soil to stand for sufficient time to ensure uniform distribution of moisture throughout the soil mass.
2. With about 8 g of soil so prepared, make a ball and roll it on the glass plate with hand, with pressure just sufficient to roll the soil mass into a thread of uniform diameter throughout its length. When the diameter of the thread reaches 3 mm, kneed the soil together to a uniform mass and once again roll it. Continue the process until the soil thread just crumbles at 3mm diameter.
3. Collect the crumbled soil threads in a container and determine the corresponding water content by oven drying method.
4. Repeat the test to have three trials.
5. Report the average water content rounded off to the nearest whole number as the plastic limit of the soil.