Cleaning muddy water

Year level: Lower primary/Middle primary Learning outcome Students will make a simple sand and gravel filter to clean muddy water and make it suitable for washing (not drinking). Read Collecting water, wells and pumps in Niger Discuss Would the water from a well with a handbuilt rim be safe to use? (There is likely to be contamination from mud and animal wastes.) Would it be safe to drink? To cook with? To wash with? To water plants? To give to animals? What could happen if you drank it? How can the water be ‘cleaned’? Preparation (for each group) One cup of muddy water Flower pot Metal stand for flower pot to allow drainage Clean glass jar Two cups of sand Two cups of gravel Absorbent paper (like paper towel or blotting paper) Method 1. Line the flower pot with absorbent paper so that it comes up the sides of the pot. 2. Pour in the gravel. 3. Pour in the sand. 4. Place the flower pot in the metal stand. 5. Place the jar under the drainage hole of the flower pot 6. Stir your cup of muddy water and slowly pour this into the middle of the flower pot. 7. Observe the water that drains from the flower pot into the jar. Questions to answer 1. What colour was the muddy water? 2. What colour was the filtered water? 3. How well did your filter work? What did it remove from the muddy water? 4. Were other students’ filters as good as yours? Why/why not? 5. How could you use this filtered water? Assessment task Draw your water filter and explain how it works. Describe how it could assist people who do not have access to clean water. See Activity: Water safe to drink for how to purify the water.