Water Filter Engineering Challenge
Stack up to five filter layers, pour simulated dirty water through, and see how particles, chemicals, and bacteria are removed at each stage. Compare designs by cleanliness score and cost per liter to find the most efficient solution.
Guided Experiment: Filter Stack Design Challenge
If you add more filter layers, do you expect the cleanliness score to always increase? What happens to cost as you add layers?
Write your hypothesis in the Lab Report panel, then click Next.
Quick Presets
Filter Column
Controls
Available Materials
Filter Stack (0/5) — drag to reorder
No layers added yet. Click a material above to add it.
Water Quality Score
Cost Analysis
Data Table
(0 rows)| # | Configuration | Layers | Materials | Cleanliness Score(/100) | Cost/Liter($) | Rating |
|---|
Reference Guide
How Filtration Works
Filtration removes contaminants from water through three main mechanisms. Physical filtration traps particles in pore spaces between grains of sand or gravel. Chemical filtration uses adsorption, where activated charcoal binds dissolved chemicals, chlorine, and odor molecules to its porous surface. Biological filtration, performed by materials like ceramic, blocks bacteria and protozoa that are too large to pass through microscopic pores.
In a layered filter, each material removes a fraction of the contaminants remaining after the layer above. This multiplicative effect means three imperfect layers can combine to produce water far cleaner than any single layer could achieve alone.
Real Water Treatment
Municipal water treatment plants use a similar multi-stage approach. Coagulation and flocculation cause small particles to clump together. Sedimentation lets heavy flocs settle out. Filtration through sand and gravel removes remaining solids. Activated carbon removes taste and odor compounds. Finally, disinfection with chlorine or UV light kills any remaining pathogens.
In remote and developing regions, ceramic pot filters and biosand filters use the same principles modeled in this lab to provide affordable safe drinking water without electricity or chemicals.
Engineering Trade-offs
Every filter design involves trade-offs between performance and cost. Adding more layers increases cleanliness but also increases cost per liter and slows flow rate. Engineers must consider the contaminant profile of the source water. A well that is biologically contaminated benefits most from ceramic layers, while surface water high in agricultural chemicals needs activated charcoal.
The efficiency ratio (cleanliness score divided by cost) is one way to compare designs. A low-cost filter that achieves 80/100 may be preferable in a school setting over a high-cost filter achieving 99/100 if budget constraints limit deployment.
