Chaffing and winnowing

Imagine you have a big bowl of grain - like wheat or barley - and you want to separate the good bits from the bad bits. But how do you do it?

Well, first you need to chaff it! Chaffing means you take the grain and you bash it up. This makes the husks - the tough outer layer that protects the grain - break away from the actual grain. These husks are called "chaff".

Now you have a mixture of broken-up chaff and actual grain. It still isn't separated! So what do you do next? Winnowing!

Winnowing involves taking the mixture of chaff and grain, and throwing it into the air. As it falls back down, the chaff - being lighter - will blow away in the wind or be caught in a sieve or screen. The heavier grain will fall back down to the ground.

So now you have two piles: one of the light, fluffy chaff and one of the heavier, more valuable grain. Voila! Separated!