Page 72 - Viva ICSE Science 5 : E-book

Separating insoluble solids

Insoluble solids in water can be separated by methods like sedimentation and
decantation, and fi ltration.

Sedimentation and decantation: These methods together are suitable for the

separation of insoluble solids which are heavier than water. By allowing heavy particles
to settle down, clear water can be

obtained on top which is poured into glass rod
another container. The settling down of
heavy particles at the bottom of the vessel

is called sedimentation. Once all the solids
insoluble
get settled, we pour the clear water at the impurities
top of the jar slowly into another jar. This Sedimentation Decantation

is called decantation.

Filtration: This technique is better as it helps in separation
f ilter paper
of very small insoluble solids also which are not removed by
funnel
sedimentation and decantation. In this method, the solution
is made to pass through a fi lter paper. The fi lter paper acts as

a sieve and does not allow even the smallest particles to pass

Filtration through it.

ACTIVITY TIME

To separate insoluble solids from water by fi ltration
You Need:
Two beakers, a funnel, a piece of fi lter paper, water and sand

What to Do:
• Place the fi lter paper inside the funnel.

• Place the funnel on an empty beaker.
• Now mix a small quantity of sand with water in another beaker.
• Pour the solution on to the funnel.
• Observe what happens.

You will observe that clear water collects in the fl ask and the sand
particles get trapped by the fi lter paper. This process is termed as
fi ltration. It is used to separate large-sized insoluble solids from the
liquid.

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