6. Homemade Water Filter

Build a simple water filter using a plastic bottle, sand, gravel, and activated charcoal. Cut the bottle in half and layer the materials inside, starting with charcoal, then sand, and finally gravel. Pour dirty water through the filter and observe how each layer removes different types of impurities.
This hands-on project demonstrates the principles of mechanical and chemical filtration, similar to processes used in municipal water treatment plants. It’s a practical way to understand how clean drinking water is produced around the world. For further exploration, visit National Geographic Water Filtration.




