1. Separation Of Substances

2. What is Separation?
Separation means removal of substances from a mixture of two or more substances. 1) Separating stones from rice 2) Separating tea from tea leaves 3) Churning milk to obtain butter

3. Why do we separate substances?
To obtain two different, but useful components
To remove non-useful components
To remove impurities or harmful components
To group substances of different sizes

4. Methods of Separation
Used for separating large sized impurities like stones and husk from rice, wheat or pulses.
Handpicking
Used for separating grains from stalks. Machines can also be used for the process.
Threshing

5. Used to separate heavier and lighter components of a mixture by wind or by blowing air. Example: Separation of lighter husk particles from heavier seeds of grain.
Winnowing
Used when components of a mixture have different sizes. Example: Pebbles and stones removed from the sand.
Sieving

6. Are there any other methods of Separation?
Sedimentation
Separation of 2 components in such a way that the heavier substance settles down
Lighter liquid
Heavier substance

7. Decantation
Separation of 2 components that do not mix well with each other. For example separation of oil and water. While water settles down being heavier than oil, the oil forms the top layer which is then separated by Decantation

8. Filtration
Separation of solids from liquids either by using a filter paper or a strainer. For example separating tea from tea leaves using a strainer or separating mud from water using a filter paper.
Strainer
Filter paper

9. Salt crystals left behind after evaporation
Evaporation is used when we want to get back a substance that has been dissolved.
Example: Getting salt out of salty water
The salty water is put into an evaporating basin (or any shallow dish such as a saucer). It is left in a warm place and the water evaporates leaving behind the salt crystals.
Salt crystals left behind after evaporation

10. Condensation on a window during a rain shower
Condensation is the process by which a substance changes from the gas phase to the liquid phase
Water vapor condenses into liquid water after making contact with the surface of a cold bottle
Condensation on a window during a rain shower

11. Can water dissolve any amount of a substance?
Water dissolves different amounts of soluble substances in it. A saturated solution is one in which no more of that substance can be dissolved. More of a substance can be dissolved in a solution by heating it.

12. Now can you guess which method should be used to separate the following substances
Stones from Grain
Mixture of Pebbles and Stones
Mixture of Dry Sand with Sawdust or Powdered Dry Leaves
Mixture of Tea and Tea Leaves

13. Ques.-Ans. Round
Q.2What is Separation? Q.2Why do we separate substances? Q.3 What are Methods of Separation? Q.4 What are Sedimentation? Q.5 What are filtration ?

14. References
NCERT Book For Class 6th Internet