Make a Recycled Water Filter

In this making project, children turn a recycled plastic bottle into a simple water filter and watch muddy water look clean again. It is a hands-on activity for ages 3 to 7, and it works well at home, in a classroom or outdoors.

Children start by gathering what they need: a plastic bottle, a coffee filter, charcoal, gravel, sand and soil, and some little stones. An adult cuts the bottle in half. The top half goes upside down inside the bottom half, and the coffee filter goes in. Then the layers are added one at a time: charcoal first, then gravel, then sand and soil, then more gravel, and little stones on top. Finally, the filter goes outside, ready to make clean water.

The idea behind it is that water can be cleaned as it passes through different materials, and that clean water is something everyone needs. The project links to the global goal of Clean Water and Sanitation, and shows how a bottle that might have been thrown away can be given a new job.

To get children talking, ask: what do you think each layer is catching? Why do we need clean water? Where does the muddy water go once it has been through the filter? You could ask children to guess before they pour, then compare the water before and after. A note for grown-ups: filtered water made this way is for looking at and learning from, not for drinking.