For you to do
You'll turn a cut bottle upside-down into a funnel, pack it with layers, and pour muddy water through. Then you'll change the layers to get clearer water.
Grown-up help
All on your own — outside or over a sink is easiest.
Build the filter
Looks clean ≠ safe
Filtered water can still have germs. This is about clearing dirt, not making drinking water. Don't drink it.
- Cut the bottle in half; flip the top half upside-down into the bottom half (cap off, like a funnel).
- Add layers from the bottom up: cloth, then sand, then gravel.
- Pour your muddy water in slowly and watch what comes out the bottom.
Redesign
Change one layer — more sand, an extra cloth, finer gravel — and pour the same muddy water through. Compare how clear it comes out.
What's happening
Each layer of the filter **system** traps different sized bits: gravel catches big stuff, sand catches fine stuff, cloth catches the rest. By changing one **variable** at a time and using careful **observation**, each **iteration** of your design gets clearer water.