The framework is organized by its three primary dimensions: (1) scientific and engineering practices, (2) crosscutting concepts, and (3) disciplinary core ideas: see Box 2-1. This three-part structure signals an important shift for science education and presents the primary challenge for assessment design: to find a way to capture and support students’ developing proficiency along the intertwined dimensions.
BOX 2-1
THE THREE DIMENSIONS OF THE FRAMEWORK 1 Scientific and Engineering Practices
1. Asking questions (for science) and defining problems (for engineering) 2. Developing and using models
3. Planning and carrying out investigations 4. Analyzing and interpreting data
5. Using mathematics and computational thinking
6. Constructing explanations (for science) and designing solutions (for engineering) 7. Engaging in argument from evidence
8. Obtaining, evaluating, and communicating information 2 Crosscutting Concepts
1. Patterns. 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: Mechanism and explanation. 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 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.
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.
5. Energy and matter: Flows, cycles, and conservation. Tracking fluxes of energy and matter into, out of, and within systems helps one understand the systems’ possibilities and limitations.
Dimension 1: Scientific and Engineering Practices
Dimension 1 identifies eight important practices used by scientists and engineers, such as modeling, developing explanations or solutions, and engaging in argumen- tation. The framework emphasizes that students need to actively engage in these scientific and engineering practices in order to truly understand the core ideas in the disciplines. The introduction of practices is not a rejection of the importance
6. Structure and function. The way in which an object or living thing is shaped and its substructure deter- mine many of its properties and functions.
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.
3 Disciplinary Core Ideas Physical Sciences
PS1: Matter and its interactions
PS2: Motion and stability: Forces and interactions PS3: Energy
PS4: Waves and their applications in technologies for information transfer Life Sciences
LS1: From molecules to organisms: Structures and processes LS2: Ecosystems: Interactions, energy, and dynamics LS3: Heredity: Inheritance and variation of traits LS4: Biological evolution: Unity and diversity Earth and Space Sciences
ESS1: Earth’s place in the universe ESS2: Earth’s systems
ESS3: Earth and human activity
Engineering, Technology, and Applications of Science ETS1: Engineering design
ETS2: Links among engineering, technology, science, and society SOURCE: National Research Council (2012a, pp. 3, 84).
of engaging students in inquiry as a component of science learning but rather a clarification that highlights the diversity of what scientists actually do.
The framework asserts that students cannot appreciate the nature of scien- tific knowledge without directly experiencing and reflecting on the practices that scientists use to investigate and build models and theories about the world. Nor can they appreciate the nature of engineering unless they engage in the practices that engineers use to design and build systems. The opportunity to learn by experi- encing and reflecting on these practices, the framework’s authors note is important because it helps students understand that science and engineering are not a matter of applying rote procedures. Engaging in and reflecting on the practices will help students see science as an iterative process of empirical investigation, evaluation of findings, and the development of explanations and solutions. Likewise, it will help students see engineering—a process of developing and improving a solution to a design problem—as both creative and iterative.
Dimension 2: Crosscutting Concepts
The framework identifies seven crosscutting concepts that can help students link knowledge from the various disciplines as they gradually develop a coherent and scientific view of the world. These crosscutting concepts are fundamental to understanding science and engineering, but they have rarely been taught or have not been taught in a way that fosters understanding of their cross-disciplinary util- ity and importance. Explicit attention to these concepts can help students develop an organizational framework for connecting knowledge across disciplines and developing integrated understanding of what they learn in different settings. The crosscutting concepts will be reinforced when they are addressed in the context of many different disciplinary core ideas. The framework posits that if this is done intentionally, using consistent language across years of schooling, students can come to recognize how the concepts apply in different contexts and begin to use them as tools to examine new problems. The idea that crosscutting concepts are fundamental to understanding science and engineering is not a new idea. Chapter 11 of Science for All Americans could not be clearer about the impor- tance of crosscutting concepts and how they apply across the different areas of science.2
Dimension 3: Disciplinary Core Ideas
The framework identifies disciplinary core ideas for the physical, life, and earth and space sciences and for engineering, technology, and applications of science. The framework makes clear that the purpose of science education is not to teach all the details—an impossible task—but to prepare students with sufficient core knowledge and abilities so that they can acquire and evaluate additional informa- tion on their own or as they continue their education.
The dimension of core ideas is extremely important. Education structured around a limited number of core ideas allows the time necessary for students to explore ideas in greater depth at each grade level and engage in the full range of practices. This dimension is in part a practical idea that has gained currency as people have recognized that curricula and standards that cover many details are too broad to provide guidance about priorities and can lead to instruction that is “a mile wide and an inch deep” (Schmidt et al., 1999). Research on science learn- ing also supports the idea that learning should be linked to organizing structures (National Research Council, 2007).