Methods of separation
The methods of separating mixtures into their components depend on the type of mixture.
● Handpicking and Filtration
In heterogeneous mixtures, the particles are visible to the naked eye. Hence methods like filtration and handpicking can be used to separate the components.
For example,
A mixture of rice grains mixed with some grains of wheat can be separated by handpicking the two types of grains.
Rice grains soaked in water can be separated by filtration.
● Evaporation
In homogeneous mixtures, the solute and solvent are completely dissolved to make a solution. In this case, the method of evaporation can be used.
For example, when a solution of salt and water is heated, the water molecules evaporate leaving the salt behind.
The evaporation process is used in salt pans across our country to make salt.
● Centrifugation
This method is used to separate components of a colloid. The centrifugation process is based on the principle that the denser particles are forced to the bottom and the lighter particles stay at the top when spun rapidly.
A machine called a centrifuge works on this principle. It has a container that rapidly rotates.
Centrifuge
For example,
Milk is a colloid that has fat globules dispersed within a water-based solution. A churner which also acts as a centrifuge separates the cream from milk. It allows the cream to rise while the liquid components of the milk settle down.
Centrifuge can also be used to separate the heavier plasma cells of the blood.