Two grade 10 classes did this challenge. We were very interested in how water is treated before it comes out of our taps – it is something we had never really thought of before. We discussed how water is cleaned in different countries and felt sorry for people who have to collect water out of the nearest river. This water may not be fit to drink and could cause water bourne diseases. Clean water is just taken for granted. We then tried different ways to purify dirty water. We first just filtered the water. It looked clean after filtration, but we decided it would still not be fit to drink as there may be harmful germs and chemicals still in the water. We then boiled the water – this would have got rid of the germs. Sophisticated methods would be needed to get rid of any unwanted chemicals still in the water. We then made a filter using a plastic bottle. Cotton wool, filter paper, stones, fine and course sand. This worked pretty well and the water looked a lot cleaner at the end. We each pledged to do a water saving action at the end of the challenge.