What you need:
• Clear plastic bottle e.g. old cola bottle
• a cup full of gravel or small pebbles
• three cups of river sand
• a brick, or small block of wood, about 15 cm tall to stand the bottle on
• a straight stick or reed with a diameter of about 0,5 cm and about 10 cm long
• a cup or glass
• a sharp blade or scissors
1. Wash your own hands well with soap, including between the fingers.
2. Wash the bottle, the pebbles, the sand, the stick and the glass with soap and rinse well.
3. Cut the narrow top of the bottle off so that you can easily get the pebbles and sand into it.
4. Put a layer of pebbles in the bottom – about 3 cm deep.
5. Put a layer of sand on top of that – about 6-10cm deep.
6. Cut a small hole in the bottom edge of the bottle so that the stick will go in tightly at an angle, pointing down. Push the stick into the pebble layer.
7. Put the bottle and stick on the brick or wood, and the cup under the stick.
8. Pour a cupful of muddy water into the top of the bottle. It will filter through the sand and pebbles and run down the stick into the cup.
9. Transfer the cupful of filtered water to a clean bottle. Repeat, cup by cup.
10. You may need to add more clean, fine sand if you want the water clearer – experiment with the best amount. .