“Makeshift water filter” experiment

How to make a water with charcoal and sand

You know the drill: you’re out camp­ing with friends, and you don’t have enough wa­ter. In this ex­per­i­ment, you’ll learn how to pu­ri­fy wa­ter from the near­est pud­dle. You only need a plas­tic bot­tle, sand and a few burnt logs.

Safe­ty pre­cau­tions

Be sure to boil the wa­ter af­ter fil­tra­tion. Since wa­ter may con­tain heavy met­als, it is rec­om­mend­ed for util­i­ty pur­pos­es, and should be con­sumed if ab­so­lute­ly nec­es­sary.

Reagents and equip­ment:

  • char­coal (100 g);
  • sand (300 g);
  • plas­tic bot­tle with a lid;
  • util­i­ty knife;
  • cot­ton wool;
  • awl.

Step-by-step in­struc­tions

Cut the bot­tom off of the plas­tic bot­tle. Un­screw the lid of the bot­tle, make a hole in it with the awl and place cot­ton wool in the lid. Close the bot­tle and turn it up­side down. Pour lay­ers of sand and char­coal in the bot­tle. The more lay­ers, the more ef­fec­tive the pu­rifi­ca­tion will be. The fil­ter is ready!

Pro­cess­es de­scrip­tion

Dirty wa­ter con­tains many or­gan­ic and min­er­al im­pu­ri­ties, as well as var­i­ous in­sol­u­ble par­ti­cles of dust and earth. The sand pu­ri­fies the wa­ter of in­sol­u­ble par­ti­cles. Char­coal has good ad­sorp­tion and so ad­sorbs or­gan­ic and min­er­al im­pu­ri­ties. How­ev­er, this fil­ter has a con­sid­er­able draw­back: it does not pu­ri­fy wa­ter from bac­te­ria and heavy met­als. So af­ter fil­tra­tion the wa­ter must be boiled well.