Can you design a simple water filter using everyday materials? What would you include and why?
A simple water filter can be designed using a plastic bottle cut in half with the following layers from top to bottom:
(1) Coarse sand – to trap large particles and sediments.
(2) Fine sand – to filter smaller particles.
(3) Gravel or small stones – to support the sand layers and allow water flow.
(4) Cotton cloth or cotton wool – to catch fine particles before water exits.
(5) Activated charcoal (optional) – to remove odours and some chemicals.
The filter works by passing dirty water through these layers, each removing progressively smaller impurities. The coarse materials at the top catch large particles, while finer materials below catch smaller impurities.
This mimics natural filtration that occurs when water passes through soil layers.
Explanation
The chapter discusses water pollution and the importance of clean water. While it does not provide specific instructions for building a water filter, students can apply their understanding of how natural filtration works. The chapter mentions that harmful things like chemicals can hide in rivers even when water looks clean, emphasising the need for proper water treatment.
Solution Steps
Use a plastic bottle cut in half as the container for the filter
Layer coarse sand at the top to trap large particles and sediments
Add fine sand to filter smaller particles
Place gravel or small stones to support the sand layers and allow water flow
Use cotton cloth or cotton wool to catch fine particles before water exits
Optionally include activated charcoal to remove odours and some chemicals
The design mimics natural filtration through soil layers