It is easy to take clean drinking water for granted, but for many people around the world access to clean water is difficult. We thought about whether it was possible to create a filter that would turn very dirty water into clean water. We thought about trying out layers of different materials including paper, cotton wool, washing up cloths and even pairs of old tights! As you can see from the photos, the results varied depending on the combination of materials, some looked cleaner than others. However, we know that there could also be pollutants and bacteria in the water still, so even if it looked clean it might not be good to drink.