Handpicking, winnowing, sieving, sedimentation, decantation and filtration are some of the methods of separating substances from their mixtures. Husk and stones could be separated from grains by handpicking. The Husk is separated from heavier seeds of grain by winnowing. We all have seen our parents and grandparents separating small stones or pebbles from the rice grains, pulses, filtering tea leaves before serving tea and a lot more. The practice of separation of substances is usually required to remove or separate the necessary substances from their mixtures.