Most current standards for science are built upon the belief that there are BIG concepts that cut across the boundaries that separate the various disciplines of science. Crosscutting concepts have application across all domains of science: life, physical, earth and space, engineering, and even environmental. They are the “big ideas” that connect all of the sciences and help to make sense of nature. As such, they are a way of linking the different domains of science. The crosscutting concepts include:
Observed patterns of forms and events guide organization and classification, and they prompt questions about relationships and the factors that influence them.
2. Cause and effect
Events have causes, sometimes simple, sometimes multifaceted. A major activity of science is investigating and explaining causal relationships and the mechanisms by which they are mediated. Such mechanisms can then be tested across given contexts and used to predict and explain events in new contexts.
3. Scale, proportion, and quantity
In thinking scientifically about systems and processes, it is essential to recognize that they vary in size (e.g., cells, whales, galaxies), in time span (e.g., nanoseconds, hours, millennia), in the amount of energy flowing through them (e.g., light bulbs, power grids, the sun), and in the relationships between the scales of these different quantities. The understanding of relative magnitude is only a starting point. As noted in Benchmarks for Science Literacy, “The large idea is that the way in which things work may change with scale. Different aspects of nature change at different rates with changes in scale, and so the relationships among them change, too”. Appropriate understanding of scale relationships is critical as well to engineering—no structure could be conceived, much less constructed, without the engineer’s precise sense of scale.
4. Systems and system models
The natural and designed world is complex; it is too large and complicated to investigate and comprehend all at once. Scientists and students learn to define small portions for the convenience of investigation. The units of investigations can be referred to as ‘systems.’ A system is an organized group of related objects or components that form a whole. Systems can consist, for example, of organisms, machines, fundamental particles, galaxies, ideas, and numbers. Systems have boundaries, parts, resources, flow, and feedback. Scientists and students develop models to study and understand complex systems.
5. Energy and matter
Energy and Matter are essential concepts in all disciplines of science and engineering, often in connection with systems. “The supply of energy and of each needed chemical element restricts a system’s operation—for example, without inputs of energy (sunlight) and matter (carbon dioxide and water), a plant cannot grow. Hence, it is very informative to track the transfers of matter and energy within, into, or out of any system under study.
6. Structure and function
The way in which an object or living thing is shaped and its substructure determine many of its properties and functions. The shape and stability of structures of natural and designed objects are related to their function(s). The functioning of natural and built systems alike depends on the shapes and relationships of certain key parts as well as on the properties of the materials from which they are made. For example, understanding how a bicycle works is best addressed by examining the structures and their functions at the scale of, say, the frame, wheels, and pedals. However, building a lighter bicycle may require knowledge of the properties (such as rigidity and hardness) of the materials needed for specific parts of the bicycle. In that way, the builder can seek less dense materials with appropriate properties.
7. Stability and change
Stability denotes a condition in which some aspects of a system are unchanging, at least at the scale of observation. Stability means that a small disturbance will fade away—that is, the system will stay in, or return to, the stable condition. For natural and built systems alike, conditions of stability and determinants of rates of change or evolution of a system are critical elements of study.
As one of the strands of three-dimensional learning, crosscutting concepts are not meant to be taught separately from the other two dimensions. Instead, they are meant to be interwoven throughout instruction. Teaching crosscutting concepts in the context of a curriculum’s subject matter is key because they reinforce key ideas and provide a common vocabulary for science and engineering. It’s also important to note that crosscutting concepts are essential for all students to learn, not only for high achievers who require extension activities. Crosscutting concepts help students make connections and build knowledge, benefiting every student regardless of their starting point.
Guiding Principles for How the Crosscutting Concepts Should Be Used
- Crosscutting concepts can help students better understand core ideas in science and
- Crosscutting concepts can help students better understand science and engineering practices.
- Crosscutting concepts should grow in complexity and sophistication across the grades.
- Crosscutting concepts should not be assessed separately from practices or core ideas.
- Crosscutting concepts can provide a common vocabulary for science and engineering.
- Crosscutting concepts are for all students.
Despite the fact that crosscutting concepts aren’t new, the instructional philosophy for explicitly integrating them into three-dimensional learning is a new approach. By being more intentional in lesson planning and actively engaging with students during instruction, teachers can help students develop a coherent and scientifically-based view of the world.
Crosscutting concepts have value because they provide students with connections and intellectual tools that are related across the differing areas of disciplinary content and can enrich their application of practices and their understanding of core ideas.