The global experiment continues! Scientists, educators, and students around the world are uniting to conduct the largest experiment ever. The subject is water, our most precious natural resource. This kit offers you the tools you need to participate. Test water quality with pH analysis. Build a water filter tower to clean dirty water. Experiment with water purification by evaporation. Learn how science can be used to give people around the world access to clean water. See water.chemistry2011.org for additional information.