Question

Define the following term:
Winnowing

Answer 1

Hint: This is a method of separation which is used to remove the heavier components from the lighter substances. This is the agricultural method used by ancient cultures to remove the husk from heavy grains.

Complete answer:
- Winnowing term is used for the separation of grains from straw with the help of wind. It is the simplest form that involves throwing the mixture into the air so that the wind can blow the lighter chaff away. However, the heavier grains fall back down without any impurities.

- Winnowing is completely based on the fact that if the mixture contains two types of components with different weights i.e. one is lighter and the other is heavier then they both can be easily separated by blow of air. The mixture is allowed to drop vertically from the height so that the lighter components can be removed by the force of the air. The heavier particle-like wheat grains form a separate stack when it falls vertically downward.

- There is another method to remove the dirt from pulses in which water is added to the pulses. Dirt gets dissolved in water and the husk will float on top because it is lighter in weight and pulse grains settle down. The winnowing process was automated by the creation of additional winnowing machines like fanning mills. Nowadays, various machines are available for the removal of impurities from grains. Machines make the work easy and save time and energy.

Note:
-The main advantage of this process is that it does not work for materials heavier than grains like stones.
-Sedimentation involves water instead of wind or blow of air.