The modern pre-K–12 science classroom is defined by hands-on learning—the notion, advanced a century ago by TC’s John Dewey, that students are more likely to learn well when they are challenged by their environment to make sense of experiences and successfully carry out activities that are of interest or concern to them.

But how can students make sense of aspects of the environment that are too large or too small to be seen in the classroom—or that happen too slowly to observe?

 

“Global climate change is happening, caused by rapidly increasing atmospheric carbon dioxide levels that are higher than they have been in 420,000 years, with inevitable consequences for sea levels, frequency and severity of storms, natural ecosystems and human agriculture,” write Lindsey Mohan, Jing Chen and Charles W. (“Andy”) Anderson of Michigan State University in their paper “Developing a K–12 Learning Progression for Carbon Cycling in Socio-Ecological Systems.” “These circumstances put a special burden on science educators. We must try to develop education systems that will prepare all of our citizens to participate knowledgeably and responsibly in the decision-making process about environmental systems.”

 

There’s still a long way to go, judging from answers by students in grades 4 through 10 to questions the Michigan State team gave them about how organic carbon is generated, transformed and oxidized. Among the central concepts many students failed to grasp: that matter is always conserved—or as the authors put it, “stuff” never goes away but only changes form; that gases are the stuff that solids and liquids become during weight loss, combustion or decomposition; and that those visible, physical processes are the product of unseen chemical changes within cells and molecules.

 

Even the most sophisticated students explain chemical changes only within “a single system, largely separate from one another,” the Michigan State researchers found—and most “do not see processes that happen in individual organisms as relevant to the flow of matter within an ecosystem.”

 

Out of this information, the Michigan group has created a four-level learning progression about the role of carbon that extends from upper elementary school through high schools. Its ultimate goal is learners who “perceive a world of hierarchically organized systems that connect organisms and inanimate matter at both atomic–molecular and large scales.”

 

Meanwhile, backed by a recent $900,000 grant from the National Science Foundation, Ann Rivet, Assistant Professor of Science Education at Teachers College, and her colleague Kim Kastens, Doherty Senior Research Scientist in Columbia’s Lamont–Doherty Earth Observatory, are tackling head-on the issues raised by tabletop models used in earth science classrooms, which are representations of Earth phenomena such as the differential heating of continents and oceans, stream erosion and deposition and other phenomena.

 

“Earth is 16 orders of magnitude larger than the classroom,” says Rivet. “So tabletop models offer imperfect analogies that, if misapplied or extended too far, create misperceptions of reality that fail to provide students with evidence that the phenomena targeted by the curricula do, in fact, occur in the real world.”

 

As a result, she says, students typically learn a lot about the tabletop models, but not much about the real-world phenomena the models are meant to simulate.

 

Working in selected eighth and ninth grade classrooms in New York’s Westchester and Rockland Counties, Rivet and Kastens will ultimately test three teaching strategies: rebalancing classroom discussions to place more emphasis on the connections between tabletop models and the earth; instructing both teachers and students in analogical reasoning (how to identify both the parallels and limitations of analogies); and giving students access to actual data sets that professional scientists have gathered about specific earth phenomena.

 

Through these approaches, Rivet and Kastens hope to develop a learning progression that will bring students to the point where they can “describe, explain and defend” scientists’ understanding of earth processes. Or as Rivet puts it, “We think science students should get in the habit of asking, ‘How do we know this is really happening?’”