ICSE Class 8 Answered

1. Threshing:

The process of beating out grains from stems is called threshing.

Threshing helps to lose grains from the scale surrounding them.

It is either done manually, by draught animals or by using machine called thresher.

Rice is threshed by hand.

Wheat and millet are threshed by making bullock walk over the bundle of crops.

2. Winnowing:

It is the process of separating the grain from the chaff.

Grains mixed with chaffs are poured from the basket.

Heavy grains drop off while lighter chaffs are blown away by wind.

Mechanical threshers are also used to perform winnowing.

A combine harvester is used in commercial farming where all the process of harvesting, threshing, winnowing occur n sequence.