A Framework for K-12 Science Education Practices, Crosscutting Concepts, and Core Ideas (2012) / Chapter Skim
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4 Dimension 2: Crosscutting Concepts
4 Dimension 2: Crosscutting Concepts
Pages 83-102
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From page 83... ...
These concepts should become common and familiar touchstones across the disciplines and grade levels. Explicit reference to the concepts, as well as their emergence in multiple disciplinary contexts, can help students develop a cumulative, coherent, and usable understanding of science and engineering.
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From page 84... ...
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. This set of crosscutting concepts begins with two concepts that are funda mental to the nature of science: that observed patterns can be explained and that A Framework for K-12 Science Education 84
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From page 85... ...
The set of crosscutting concepts defined here is similar to those that appear in other standards documents, in which they have been called "unifying concepts" or "common themes" [2-4]
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From page 86... ...
For example, biologists studying changes in population abundance of sev eral different species in an ecosystem can notice the correlations between increases and decreases for different species by plotting all of them on the same graph and can eventually find a mathematical expression of the interdependences and food web relationships that cause these patterns. Progression Human beings are good at recognizing patterns; indeed, young children begin to recognize patterns in their own lives well before coming to school.
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From page 87... ...
A major activity of science is to uncover such causal connections, often with the hope that understanding the mechanisms will enable predictions and, in the case of infectious diseases, the design of preventive measures, treat ments, and cures. Repeating patterns in nature, or events that occur together with regular ity, are clues that scientists can use to start exploring causal, or cause-and-effect, relationships, which pervade all the disciplines of science and at all scales.
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From page 88... ...
For example, although knowledge of atoms is not sufficient to predict the genetic code, the replication of genes must be under stood as a molecular-level process. Indeed, the ability to model causal processes in complex multipart systems arises from this fact; modern computational codes incorporate relevant smaller scale relationships into the model of the larger sys tem, integrating multiple factors in a way that goes well beyond the capacity of the human brain.
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From page 89... ...
Objects at the atomic scale, for example, may be described with simple models, but the size of atoms and the number of atoms in a system involve magnitudes that are difficult to imagine. At the other extreme, science deals in scales that are equally dif ficult to imagine because they are so large -- continents that move, for example, and galaxies in which the nearest star is 4 years away traveling at the speed of 89 Dimension 2: Crosscutting Concepts
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From page 90... ...
Young children can begin understanding scale with objects, space, and time related to their world and with explicit scale models and maps. They may discuss relative scales -- the biggest and smallest, hottest and coolest, fastest and slowest -- without reference to particular units of measurement.
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From page 91... ...
They can also develop an understanding of estimation across scales and contexts, which is important for making sense of data. As students become more sophisticated, the use of estima tion can help them not only to develop a sense of the size and time scales relevant to various objects, systems, and processes but also to consider whether a numeri cal result sounds reasonable.
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From page 92... ...
They then exam ine the system in detail while treating the effects of things outside the boundary as either forces acting on the system or flows of matter and energy across it -- for example, the gravitational force due to Earth on a book lying on a table or the carbon diox ide expelled by an organism. Consideration of flows into and out of the system is a crucial element of system design.
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From page 93... ...
In more complex systems, it is not always possible or useful to consider interactions at this detailed mechanical level, yet it is equally important to ask what interactions are occurring (e.g., predator-prey relationships in an eco system) and to recognize that they all involve transfers of energy, matter, and (in some cases)
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From page 94... ...
Teaching students to explicitly craft and present their models in dia grams, words, and, eventually, in mathematical relationships serves three purpos es. It supports them in clarifying their ideas and explanations and in considering any inherent contradictions; it allows other students the opportunity to critique and suggest revisions for the model; and it offers the teacher insights into those aspects of each student's understanding that are well founded and those that could benefit from further instructional attention.
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From page 95... ...
And studying the interactions between matter and energy supports students in developing increasingly sophisticated conceptions of their role in any system. However, for this development to occur, there needs to be a common use of language about energy and matter across the disciplines in science instruction.
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From page 96... ...
By middle school, a more precise idea of energy -- for example, the understanding that food or fuel undergoes a chemical reaction with oxygen that releases stored energy -- can emerge. The common misconceptions can be addressed with targeted instructional interventions (including student-led inves tigations)
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From page 97... ...
. For students in the middle grades, the concept of matter having a submicroscopic structure is related to properties of materials; for example, a model based on atoms and/or molecules 97 Dimension 2: Crosscutting Concepts
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From page 98... ...
At extreme flows, other factors may cause disequilibrium; for example, at a low-enough inflow, evaporation may cause the level of the water to continually drop. Likewise, a fluid at a constant temperature can be in a steady state with constant chemical composition even though chemi cal reactions that change the composition in two opposite directions are occurring within it; change the temperature and it will reach a new steady state with a dif ferent composition.
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From page 99... ...
For example, when looking at a living organism over the course of an hour or a day, it may maintain stability; over longer periods, the organism grows, ages, and eventually dies. For the development of larger systems, such as the variety of living species inhabiting Earth or the formation of a galaxy, the relevant time scales may be very long indeed; such processes occur over millions or even billions of years.
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From page 100... ...
Stable matter is a system of atoms in dynamic equilibrium. For example, the stability of the book lying on the table depends on the fact that minute distortions of the table caused by the book's downward push on the table in turn cause changes in the positions of the table's atoms.
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From page 101... ...
Thus these crosscutting concepts should not be taught in isolation from the examples provided in the disciplinary context. Moreover, use of a common language for these concepts across disciplines will help students to rec ognize that the same concept is relevant across different contexts.
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From page 102... ...
. Science College Board Standards for College Success.
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