Winnowing

Valli sees the threshed wheat lying mixed with piles of husk. Will the farmers have to handpick all those grains? That would take forever!

Try this: rub some roasted peanuts between your palms and their thin skins come off. Now blow on them. The light skins fly away and the heavier peanuts stay. Blowing air separates the heavier and lighter parts of a mixture.

Farmers use the same idea with a soop, a bamboo tray. Next day, Nana takes the children to the fields. A farmer stands on a raised platform and tips the threshed wheat from the soop into the wind:

• the heavier grains fall close by, in a heap;
• the lighter husk is carried away by the wind and falls farther off.

Separating the heavier and lighter parts of a mixture by wind or blowing air is called winnowing. It only works when one part is clearly lighter than the other, and it needs a breeze or a fan: on a completely still day there is nothing to carry the husk away.