Question

Why is hand picking is necessary after winnowing?

Answer 1

Superb...Question.
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The ans..is

Sometimes in the process of winnowing which is actually done in the pŕesence of wind...some imputities present in the substance cant get removed...so after this if we do the process of handpicking..all the impurities left behind after the process of winnowing would be removed by hand and thus it is very necessary.......

@racks

Answer 2

Hand picking :

The process in which a mixture of solid with solid is separated.

Example:

The separation of grains from the stalk after harvesting.

The dried stalks are beaten or threshed to separate the grains.

Harvesting: The process of cutting and gathering the ripened crop is called harvesting.

Winnowing - The method which is used to separate heavier substances from the lighter ones.

The mixture is allowed to fall from a height. The light components get separated from the heavier ones of wind blow or air blow. This method is used to separate lighter husk from heavier grains like wheat.

Now,

Hand picking is necessary after winnowing because some heavier substances like stones also fall with the heavier substance. So, They can be separated by the process of hand picking.