CSTA Classroom Science

Do We Really Need a Third Dimension?

By Peter A’Hearn

The NGSS has defined science learning as three-dimensional. There are Core Ideas and Science and Engineering Practices, which seem similar to content from the old standards. Then there’s this new thing- the Crosscutting Concepts.

So… do we really need the crosscutting concepts? How important are they to science? Consider a few examples from the history of science:

Galileo used a new tool, the telescope, which let him observe the universe at a different SCALE. He observed PATTERNS which he tried to establish CAUSE AND EFFECT relationships to explain. He ended up supporting a new SYSTEMS MODEL of the solar system.



Patterns in nature are often the starting point for science. 
Cross Cut Symbol for Patterns. Used with permission from CrossCutSymbols. http://crosscutsymbols.weebly.com/[/caption] 

Darwin observed PATTERNS in the distribution of living things. His reading of geology led him to understand the vast SCALE of time for change to occur. He connected a series of CAUSE AND EFFECT relationships that both explained STRUCTURE AND FUNCTION in living things and STABILITY AND CHANGE of species over time. 

Understanding global climate change required the observation of PATTERNS of climate over long and short time SCALES and identifying a CAUSE AND EFFECT relationship that could account for those patterns. To truly understand STABILITY AND CHANGE in Earth’s climate, complex SYSTEMS MODELS had be developed to account for the many ways that ENERGY AND MATTER flow and cycle through Earth’s SYSTEM.



Identifying Cause and Effect relationships is a major goal of scientific inquiry
Used with permission from CrossCutSymbols. http://crosscutsymbols.weebly.com/.[/caption] 

I have found that the Crosscutting Concepts can be challenging to explain to classroom teachers, but are always easy to explain to working scientists and engineers. Dr. Dave Polcyn, on first seeing a presentation on the NGSS Crosscutting Concepts, said, “This describes how we [scientists] think, but I don’t think I’ve ever seen it just listed this way!” I have had similar reactions from wildlife biologists, physicists, and engineers, who regard the crosscutting concepts as obvious, if usually unstated.

These encounters have led me to an easy shorthand for the three dimensions of NGSS:

The Disciplinary Core Ideas are what scientists and engineers KNOW

The Science and Engineering Practices are what scientists and engineers DO

The Crosscutting Concepts are how scientists and engineers THINK

To help keep your students and yourself thinking about the crosscutting concepts and how to apply them, I developed a series of classroom symbols that can be found at http://crosscutsymbols.weebly.com/ . There are free PDFs of small and large classroom posters and lists of questions that can be used to focus student’s thinking. I hope you enjoy thinking like a scientist!



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