Make the model: Crumple a couple of sheets of newspaper and place them in the plastic container. Drape the plastic sheet over the crumpled paper in such a way that a valley and hills are formed. Be sure that water …
Take an open marker and drop it on the model to create a trace of it on the surface of the model. This is the point of our pollution (input of untreated wastewater of a city, oil spill or something …