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3 Dimension 1: Scientific and Engineering Practices
Pages 41-82

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From page 41...
... Second, we describe in detail eight practices we consider essential for learning science and engineering in grades K-12 (see Box 3-1)
From page 42...
... Using mathematics and computational thinking 6. Constructing explanations (for science)
From page 43...
... In addition, when such procedures are taught in iso lation from science content, they become the aims of instruction in and of them selves rather than a means of developing a deeper understanding of the concepts and purposes of science [17]
From page 44...
... In reality, practicing scientists employ a broad spectrum of methods, and although science involves many areas of uncertainty as knowledge is developed, there are now many aspects of sci entific knowledge that are so well established as to be unquestioned foundations of the culture and its technologies. It is only through engagement in the practices that students can recognize how such knowledge comes about and why some parts of scientific theory are more firmly established than others.
From page 45...
... Design development also involves constructing models, for example, computer simulations of new structures or processes that may be used to test a design under a range of simulated conditions or, 45 Dimension 1: Scientific and Engineering Practices
From page 46...
... . Like scientific investigations, engineering design is both iterative and sys tematic.
From page 47...
... In contrast, scientific studies may or may not be driven by any immediate practical application. On one hand, certain kinds of scientific research, such as that which led to Pasteur's fundamental contributions to the germ theory of disease, were undertaken for practical purposes and resulted in important new technologies, including vaccination for anthrax and rabies and the pasteurization of milk to prevent spoilage.
From page 48...
... avoids the mistaken impression that there is one distinctive approach common to all science -- a single ❚ "scientific method." A Framework for K-12 Science Education 48
From page 49...
... Using mathematics and computational thinking 6. Constructing explanations (for science)
From page 50...
... A major practice of essential for specifying design criteria or parameters scientists is planning and carrying out a system- and to test their designs. Like scientists, engineers atic investigation, which requires the identifica- must identify relevant variables, decide how they tion of what is to be recorded and, if applicable, will be measured, and collect data for analysis.
From page 51...
... their designs and investigations; this allows them Because data usually do not speak for them- to compare different solutions and determine how selves, scientists use a range of tools -- including well each one meets specific design criteria -- that tabulation, graphical interpretation, visualization, is, which design best solves the problem within the and statistical analysis -- to identify the signifi- given constraints. Like scientists, engineers require cant features and patterns in the data.
From page 52...
... Engineers collaborate with their peers the best explanation for a natural phenomenon. throughout the design process, with a critical stage Scientists must defend their explanations, for- being the selection of the most promising solution mulate evidence based on a solid foundation of among a field of competing ideas.
From page 53...
... Moreover, as with scientists, they need ing in extended discussions with scientific peers. to be able to derive meaning from colleagues' texts, Science requires the ability to derive meaning evaluate the information, and apply it usefully.
From page 54...
... Asking questions is essential to developing scientific habits of mind. Even for individuals who do not become scientists or engineers, the ability to ask well defined questions is an important component of science literacy, helping to make them critical consumers of scientific knowledge.
From page 55...
... The experience of learning science and engineering should therefore develop students' ability to ask -- and indeed, encourage them to ask -- well-formulated questions that can be investigated empirically. Students also need to recognize the distinction between questions that can be answered empirically and those that are answerable only in other domains of knowledge or human experience.
From page 56...
... Building an understanding of models and their role in science helps students to construct and revise mental models of phenomena. Better mental models, in turn, lead to a deeper understanding of science and enhanced scientific reasoning.
From page 57...
... Models, particularly modern computer simulations that encode relevant physical laws and properties of materials, can be especially helpful both in realizing and testing designs for structures, such as buildings, bridges, or aircraft, that are expensive to construct and that must survive extreme conditions that occur only on rare occasions. Other types of engineering problems also benefit from use of specialized computer-based simulations in their design and testing phases.
From page 58...
... PROGRESSION Modeling can begin in the earliest grades, with students' models progressing from concrete "pictures" and/or physical scale models (e.g., a toy car) to more abstract representations of relevant relationships in later grades, such as a diagram repre senting forces on a particular object in a system.
From page 59...
... This process begins by identifying the relevant variables and considering how they might be observed, measured, and controlled (constrained by the experimental design to take particular values)
From page 60...
... These investigations can be enriched and extended by linking them to engineer ing design projects -- for example, how can students apply what they have learned about ramps to design a track that makes a ball travel a given distance, go around a loop, or stop on an uphill slope. From the earliest grades, students should have A Framework for K-12 Science Education 60
From page 61...
... As they become more sophisticated, students also should have opportunities not only to iden tify questions to be researched but also to decide what data are to be gathered, what variables should be controlled, what tools or instruments are needed to gather and record data in an appropriate format, and eventu ally to consider how to incorporate measurement error in analyzing data. Older students should be asked to develop a hypothesis that predicts a particular and stable out come and to explain their reasoning and justify their choice.
From page 62...
... Such data sets extend the range of students' experiences and help to illu minate this important practice of analyzing and interpreting data. GOALS By grade 12, students should be able to Analyze data systematically, either to look for salient patterns or to test • whether data are consistent with an initial hypothesis.
From page 63...
... As students progress through various science classes in high school and their investigations become more complex, they need to develop skill in additional techniques for displaying and analyzing data, such as x-y scatterplots or crosstabulations to express the relationship between two variables. Students should be helped to recognize that they may need to explore more than one way to display their data in order to identify and present significant features.
From page 64...
... In much of modern science, predictions and inferences have a probabilistic nature, so understanding the mathematics of probability and of statistically derived inferences is an important part of understanding science. Computational tools enhance the power of mathematics by enabling cal culations that cannot be carried out analytically.
From page 65...
... For example, structural engineers create mathematical models of bridge and building designs, based on physical laws, to test their performance, probe their structural limits, and assess whether they can be completed within acceptable budgets. Virtually any engineering design raises issues that require computation for their resolution.
From page 66...
... For example, they could use spreadsheets to record data and then perform simple and recurring calcula tions from those data, such as the calculation of average speed from measure ments of positions at multiple times. Later work should introduce them to the use of mathematical relationships to build simple computer models, using appropriate supporting programs or information and computer technology tools.
From page 67...
... For example, if one understands the theory of how oxygen is obtained, transported, and utilized in the body, then a model of the circulatory system can be developed and used to explain why heart rate and breathing rate increase with exercise. ❚ Scientific theories are developed to provide explanations aimed at illuminating the nature of particular phenomena, predicting future events, ❚ or making inferences about past events.
From page 68...
... This is an essential step in building their own understanding of phenomena, in gaining greater appreciation of the explana tory power of the scientific theories that they are learning about in class, and in acquiring greater insight into how scientists operate. In engineering, the goal is a design rather than an explanation.
From page 69...
... • Undertake design projects, engaging in all steps of the design cycle and pro• ducing a plan that meets specific design criteria. Construct a device or implement a design solution.
From page 70...
... Furthermore, design activities should not be limited just to structural engineering but should also include projects that reflect other areas of engineering, such as the need to design a traffic pattern for the school parking lot or a layout for planting a school garden box. In middle school, it is especially beneficial to engage students in engineer ing design projects in which they are expected to apply what they have recently learned in science -- for example, using their now-familiar concepts of ecology to solve problems related to a school garden.
From page 71...
... Over time, ideas that survive critical examination even in the light of new data attain consensual acceptance in the community, and by this process of dis course and argument science maintains its objectivity and progress [28]
From page 72...
... • Identify possible weaknesses in scientific arguments, appropriate to the stu • dents' level of knowledge, and discuss them using reasoning and evidence. A Framework for K-12 Science Education 72
From page 73...
... They need instructional support to go beyond simply making claims -- that is, to include reasons or references to evidence and to begin to distinguish evidence from opinion. As they grow in their ability to construct scientific arguments, students can draw on a wider range of reasons or evidence, so that their arguments become more sophisticated.
From page 74...
... , using a mix of words, diagrams, charts, symbols, and mathematics to communicate. Thus understanding science texts requires much more than sim ply knowing the meanings of technical terms.
From page 75...
... As in science, engineering communication involves not just written and spoken language; many engineering ideas are best communicated through sketches, diagrams, graphs, models, and products. Also in wide use are handbooks, specific to particular engineering fields, that provide detailed information, often in tabular form, on how best to formulate design solutions to commonly encountered engineering tasks.
From page 76...
... Students need sustained practice and support to develop the ability to extract the meaning of scientific text from books, media reports, and other forms of scientific communication because the form of this text is initially unfamiliar -- expository rather than narrative, often linguistically dense, and reliant on precise logical flows. Students should be able to interpret meaning from text, to produce text in which written language and diagrams are used to express scientific ideas, and to engage in extended discussion about those ideas.
From page 77...
... Because the spoken language of such discussions and presentations is as far from their everyday language as scientific text is from a novel, the development both of written and spoken scientific explanation/argumentation needs to proceed in parallel. In high school, these practices should be further developed by providing students with more complex texts and a wider range of text materials, such as technical reports or scientific literature on the Internet.
From page 78...
... Thus the picture of scientific reasoning is richer, more complex, and more diverse than the image of a linear and unitary scientific method would suggest [45]
From page 79...
... And as they involve themselves in the practices of science and come to appreciate its basic nature, their level of sophistication in understanding how any given practice contributes to the scientific enterprise can continue to develop across all grade levels. 79 Dimension 1: Scientific and Engineering Practices
From page 80...
... . Understanding Scientific Reasoning.
From page 81...
... . Dual space search during scientific reasoning.
From page 82...
... . Reading scientific texts: Adapting primary literature for promoting scientific literacy.


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