Let us construct a water filter with simple, everyday materials.
Take a plastic bottle and cut it into 2 halves at the centre. Use the upper half as a funnel by putting it upside down in the lower half. Make layers in it with paper napkin or a fine cloth followed by, cotton, sand and then gravel. Now pour dirty water through the filter and observe the filtered water.
Discuss the following questions amongst yourselves and with your teacher:
Why do we need to filter water before drinking?
Where do you get your drinking water from?
What will happen if we drink polluted water?
Water which is full of dust particles and impurities is unfit for human health thus we need to filter water before drinking it.
We get drinking water from government supply water or hand pump.
Polluted water have disease-carrying microorganisms and dissolved impurities which can make us seriously ill.