What is the winnowing method? What is the fundamental principle involved in this method?

Winnowing is a separation method in which heavier components of the mixture are separated from the lighter substances with the help of wind or by blowing air. [2 Marks]
Lighter husk particles are usually separated from heavier seeds of grain by this method. [1 Mark]
Winnowing is based on the principle of different weights of components of a mixture, and the rate of wind. When a mixture allows falling, the lighter particles are blown away by the wind and deposited away from the heavier particles. [2 Marks]