Imagine you are sitting down and enjoying your favorite meal, suddenly you notice something different and quickly check into the bowl, you see an insect. would you like to continue that meal? Of course not. To avoid these kinds of situation, we use method of separation of substances. As substances are mostly available in mixtures, we need to separate them from the mixture so that we can remove all the unwanted substance and obtain useful components by using different methods.
Some common methods of separation
This method involves simply picking out all the unwanted substances by hand and separating them from useful ones. The separated substances may be an impurity that has to throw away or may be that both the separated substances are useful. For example – if you separate black grapes from green ones from a mixture of the two.
When you visited your village in summer holidays, you must have seen this method that is done after Harvesting Of Crops. The stalks are dried once the wheat is harvested. Each grain is separated from the stalks so that it can be easily grounded into the floor. The method where grains are separated from stalks is called threshing. It is beating of the dry stalks to shake off the dried grains. Earlier it was done by hand, by cattle but now people are using machines to separate plenty of grains quickly.
After threshing out wheat, the grains are cleared out of husk and chaff before grinding it into flour. The method of separation of lighter and heavier particles from the mixture with the help of wind or blowing air is called Winnowing. The husk and chaff are easily separated from the grains by winnowing, where farmers drop the mixture from a height to the ground. All the heavier grains get collected at one place while the lighter impurities blow away.
It is done to separate all the substances that are of different sizes. All the smaller substances from the mixture are passed through the pores of the sieve while the sieve retains bigger components of the mixtures. You can understand this with an example- Wheat flour is a mixture of powdered wheat flour and big impurities that can be separated through a sieve. Put the flour through a sieve, the fine powder will fall through the small holes in the sieve while the big impurities will remain there.
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