Site Navigation

Your Account

Choose Language


Minor Versionm

by Procheta Mallik


Using alum, stones, sand of various grades and a filter paper, we show how muddy water may be filtered

Video Overview

    • Do not expose alum and sand to your eyes.

    • Over-dosage of alum may cause temporary dizziness, diarrhoea and vomiting (but not dangerous). Take care while handling alum.

    • Handle the cutter/scissor with care

  1. Take some muddy water in a plastic cup/beaker.
    • Take some muddy water in a plastic cup/beaker.

    • Measure half a teaspoon of alum and transfer it to the dirty water.

    • Stir it and keep it for a while till the sediments get coagulated and settle at the bottom.

    • Take a plastic bottle and cut it in half using a cutter/scissor; remove the cap .

    • Place the upper part of the bottle inverted over the lower part.

    • Cover the mouth of the bottle with filter paper.

    • Put stones over the filter paper.

    • Add crude sand after adding the stones.

    • Add fine sand on top of the crude sand.

    • Pour the muddy water containing alum over the sand on the bottle funnel.

    • Keep pouring gently/slowly as clearer water filters down into the bottom part of the bottle, drop by drop

    • Make sure filter paper is placed correctly.

    • There needs to be adequate amount of stones and sand

    • Make sure water is poured gently/slowly so that there is no overflowing over the sand filter/bottle-funnel

    • Conduct the same experiment without using alum. What do you observe?

    • How many litres of muddy water are you able to filter with this setup without the quality of the filtered water degrading?

    • At what rate is the filter able to filter the water, i.e. how long does it take to filter 100 ml or 250 ml or 1 litre of muddy water?

    • Invert the ingredients over the filter paper so that the fine sand is at the bottom and stones on top. Do you notice any change in the filtrate?

Finish Line

Vishal Bhatt

Member since: 04/26/2017

2,329 Reputation

63 Guides authored