Page 89 - Viva ICSE Science 4 : E-book

For example, a mixture of sand and water, or a mixture of chalk powder and water can
be separated by this method. If we pour sand and water, or chalk powder and water
solution over fi lter paper, we note that water passes through it easily. Whereas, sand

and chalk powder, being the insoluble solid substances, cannot pass through the fi lter
paper. They are left behind on the filter paper.

Evaporation

Evaporation is a process by which soluble substances can be separated out from a

solution. This process involves heating of a solution in order to evaporate the solvent
completely so that only the soluble solid substances are left behind.

For example, if salt water is heated, the water evaporates completely, leaving behind
only the salt crystals. Thus, common salt can be easily obtained from the salt water by

this method.

Evaporation of river water due to the heat of the sun

TIME TO REVISE

Match the following.
Column A Column B
1. Filtration (a) process of letting the heavier object settle
at the bottom
2. Evaporation (b) process of pouring out the top substance
3. Sedimentation (c) process of separation using fi lter paper
4. Decantation (d) process of separation by heating

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