4M Green Science - Clean Water ScienceLearn the science of cleaning and reusing dirty water. Build your own water filtration and desalination plant. It's a cool water science experimental kit. Children can experiement by pouring a cup of coffee into the top of the unit and the water will come out clear at the bottom. Help to save the environment. Learn the science of cleaning and reusing dirty water by conducting interesting water purification experiments. Build your own water filtration