Define winnowing.

Hint: Winnowing is the method in which, with the help of wind heavier particles of the mixture are separated from the lighter particles. This method is found to be used for separating grains from husk after the process of threshing.

Complete answer:
- In this process we can simply say that, it involves throwing off the mixture into the air so that the wind blows away the lighter particles, whereas the heavier grains fall down for recovery.
- These techniques include using a winnowing fan (which is a shaped basket shaken to raise the light particles that are called chaff.) or using a tool.
 - Nowadays a single machine is used for both the processes that are winnowing and threshing. Threshing is a method of separation stalks from grains. With the help of this single machine work for farmers becomes very easy and they are able to do their tasks at the same time.
- There are several Advantages of Winnowing found like:
  - No machines are required for this method, for its functioning. It is completely based on human activity.
  - So, we can say that it takes less time to process and is also definitely a very cheap method.
- There are also some Disadvantages of Winnowing like:
  -As we know that in this, with the help of wind heavier particles of the mixture are separated from the lighter particles. But this process does not work for materials which are heavier than grains like stones.

Note:
- Both winnowing and threshing are different processes, we must not get confused in both of these. It is the process of separating husk from grains, whereas threshing is the process of loosening grain from chaff, where grain is the edible part and chaff is the non – edible part.