Class 6
Chapter 5 Class 6 - Separation of Substances


This method is used when :-

  • Larger sized impurities need to be removed eg. rocks, pieces of dirt, husk from rice, wheat or pulses etc.
  • The quantity of impurities is not large.



  • Threshing is the method used to separate grains from stalks etc.
  • Stalks are beaten to free the grain seeds.
  • Machines are used to thresh large quantities of grain but for smaller quantities, bullock carts are used.



  • Winnowing is used to separate heavier and lighter components by wind or by blowing air.
  • It can be used to separate grain from husk or a mixture of dry sand with saw dust and dried leaves.
  • The husk particles are carried away by wind and the grains are collected below.
  • This husk is used for other purposes like feeding fodder .



  • It separates material s on the basis of their. 
  • Smaller components are able to pass through the sieve whereas bigger ones are not.
  • Eg. removing husk and stone from wheat in flour mills.


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CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo