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 componentsTo remove non-useful componentsTo remove impurities or harmful componentsTo group substances of different sizes
4 Methods of SeparationUsed for separating large sized impurities like stones and husk from rice, wheat or pulses.HandpickingUsed 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.WinnowingUsed 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? SedimentationSeparation of 2 components in such a way that the heavier substance settles downLighter liquidHeavier substance
7 DecantationSeparation 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 FiltrationSeparation 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.StrainerFilter 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 waterThe 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 phaseWater vapor condenses into liquid water after making contact with the surface of a cold bottleCondensation 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 GrainMixture of Pebbles and StonesMixture of Dry Sand with Sawdust or Powdered Dry LeavesMixture of Tea and Tea Leaves
13 Ques.-Ans. RoundQ.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 ?