Appendix G. Crosscutting Concepts Posters 3-5

1. Patterns - Observed patterns of forms and events guide organization and classification, and they prompt questions about relationships and the factors that influence them.  Patterns exist everywhere—in regularly occurring shapes or structures and in repeating events and relationships. For example, patterns are discernible in the symmetry of flowers and snowflakes, the cycling of the seasons, and the repeated base pairs of DNA.

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. Cause and effect is often the next step in science, after a discovery of patterns or events that occur together with regularity. A search for the underlying cause of a phenomenon has sparked some of the most compelling and productive scientific investigations.

3.  Scale, Proportion and Quantity - In considering phenomena, it is critical to recognize what is relevant at different measures of size, time, and energy and to recognize how changes in scale,  proportion, or quantity affect a system’s structure or performance. Scale, Proportion and Quantity are important in both science and engineering. These are fundamental assessments of dimension that form the foundation of observations about nature. Before an analysis of function or process can be made (the how or why), it is necessary to identify the what. These concepts are the starting point for scientific understanding, whether it is of a total system or its individual components.

4.  Systems and System Models - Defining the system under study—specifying its boundaries and making explicit a model of that system—provides tools for understanding and testing ideas that  are applicable throughout science and engineering. Systems and System Models are useful in science and engineering because  the world is complex, so it is helpful to isolate a single system and construct a simplified model of it.

5.  Energy and Matter - Tracking fluxes of energy and matter into, out of, and within systems helps one understand the systems’ possibilities and limitations. Energy and Matter are essential concepts in all disciplines of science and engineering, often in connection with systems.

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. Structure and Function are complementary properties. “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.

7.  Stability and Change - 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. Stability and Change are the primary concerns of many, if not most scientific and engineering endeavors. “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.