World Water Day / Muddy Water Filter Challenge
Muddy Water Filter Challenge
Teams build layered filters from cut plastic bottles, gravel, sand and cloth, then race to make muddy water look as clear as possible and learn why treatment plants do more.
How to run it
- Cut plastic bottles in half ahead of time and turn the tops upside down into the bottoms as funnels.
- Give teams gravel, sand, cotton wool, cloth and coffee filters to layer however they think works best.
- Pour the same amount of muddy water through each filter and compare the results in clear cups.
- Let teams redesign and test again.
- Explain that filtered water may look clear but is still not safe to drink without proper treatment.
You will need
- plastic bottles
- gravel
- clean sand
- cotton wool
- cloth scraps
- coffee filters
- muddy water
- clear cups
Make it easier or harderYounger children can follow one set layer order; older children can test one material at a time and rank the results.
SafetyEducators cut the bottles and tape sharp edges; make it clear the filtered water must never be drunk.
My Time Our Place · Outcome 4, Outcome 5Children test, compare and improve designs, explaining their findings to others as confident learners.
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