Page 65 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

In order to separate insoluble particles
in a liquid mixture on the basis of their
mass difference, Centrifuge (Figure
4.11) is used. The process is known
as centrifugation.

Centrifuge When the centrifuge rotates
Fig. 4.11
This method is used for separating butter from curd.
Chromatography

Put a black spot using a sketch pen on one end of a filter paper
cut like a ribbon. Keep this dipped in the water in a beaker as
shown in Figure 4.12 (a).

What can be observed when the water level in the filter paper
ascends?
What can be inferred from the different colours found in the
Fig. 4.12 (a) filter paper?
This method of separating components of a mixture is known as
Chromatography.

Chromatography is the method used to separate more than one
solute dissolved in the same solvent. This method was first
employed for separating coloured substances and hence this
process came to be known as Chromatography.

Look at some of the occasions where
Fig. 4.12 (b)
chromatography is employed.
Adsorption-The basis of
Chromatography to separate components from dyes.
Capillarity is the phenomenon by which liquids to separate poisonous substances
rise through micropores against gravitation. mixed with blood.
The solute particles move along with the Hope you are now familiar with some
solvent which rises through the micropores in
the filter paper. Due to the attraction between of the methods of separating
the filter paper and solute particles they get components from a mixture. The
attached to the surface of the filter paper. This components of a mixture will have to
is called adsorption. Particles are separated be separated by employing the above
on the surface of filter paper on the basis of methods as well as by some other
the difference in the rate of adsorption.
modern techniques. You will learn them
in higher classes.
Basic Science VIII
64 64 Basic Science VIII