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Potable water

Potable means drinkable. The water that is safe for drinking is called potable water. The
tap water which we get through pipes in our home is clean and usually without any foul
smell. It is said to be safe for drinking. The clear, transparent and odourless tap water may
not be always safe for drinking because it may contain some microorganisms. The tap
water can be further purified at home to make it safe for drinking. The various methods
are

1. By filtering
A popular household water filter is a candle-type water filter. In this type of water filter,
the tap water is filled in a container having candles made up of porcelain fixed in it. The
water gets filtered through the candles. And drops into another container kept below.
The collected water is safe for drinking.
In the electric water filter like (pure it, aquaguard) resin filters are used to remove solid
particles present in the water, and UV radiations are used to kill all the harmful micro-
organisms present.
Activity
We can ourselves construct a simple water filter by using the commonly available
materials around us. Let us take a plastic bottle and cut it into two halves. Let us turn
the upper half of the plastic bottle upside down and place it in the lower half of the
plastic bottle. Let us add layers to the upper part of the water bottle with a piece of fine
cloth, followed by sand, and then gravel. Our water filter is ready. Now, let us p[our
dirty water from the top end of the filter. We will see that clear water collects in the
lower half of the plastic bottle slowly. The suspended impurities of dirty water have
been removed by filtration through the water filter.

2. By boiling
Water can be made absolutely safe for drinking by boiling. When water is heated, it
o
boils at 100 C. at this high temperature, all the harmful micro-organisms present in the
water are killed.
3. Chlorination
It is a commonly used chemical method for p[urifying water. It is done by adding
chlorine tablets to water. It kills all the harmful micro-organisms present in water and
makes it safe for drinking. Bleaching powder can also be used for chlorination of water.
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