When teachersguide students in gaining awareness that industrial agriculture writ large, for example, results in chemical runoff from nitrogen-based fertiliers in the Mississippi River that in turn creates a massive dead zone in the Gulf of Mexico so large that it is visible to the human eye through satellite distant imaging, students are able to grasp the basis for sustainable agriculture.
In this, Plowden was heavily influenced by Jean Piaget, a psychologist who argued that children's ability to assimilate knowledge progressed at its own pace and therefore teachers should guide pupils to discover things for themselves.