Engaging Students in Scientific Practices: What Does Constructing and Revising Models Look like in the Science Classroom? Understanding a Framework for K-12 Science Education

The Next Generation Science Standards (NGSS)--now in development-will be based on A Framework for K-12 Science Education released by the National Research Council last summer. The NGSS will use four key ideas from the Framework: (1) a limited number of core ideas of science, (2) the integration or coupling of core ideas and scientific and engineering practices, (3) crosscutting concepts, and (4) the development of the core ideas, scientific practices, and crosscutting concepts over time. In the December issue of The Science Teacher, Rodger Bybee provided an overview of the Scientific and Engineering practices and showed how they are a refinement and further articulation of what it means to do scientific inquiry in the science classroom (2011). The Framework identifies seven scientific and engineering practices that should be used in science classrooms. These practices reflect the multiple ways in which scientists explore and understand the world and the multiple ways in which engineers solve problems. These practices include: * Asking questions (for science) and defining problems (for engineering) * Developing and using models * Planning and carrying out investigations * Analyzing and interpreting data * Using mathematics, information and computer technology, and computational thinking * Constructing explanations (for science) and designing solutions (for engineering) * Engaging in argument from evidence * Obtaining, evaluating, and communicating information In this article, we look in-depth at scientific practice #2--developing, evaluating, and revising scientific models to explain and predict phenomena--and what it means for classroom teaching. Models provide scientists and engineers with tools for thinking, to visualize and make sense of phenomena and experience, or to develop possible solutions to design problems (NRC 2011). Models are external representations of mental concepts. Models can include diagrams, three-dimensional physical structures, computer simulations, mathematical formulations, and analogies. It is challenging for learners to understand that all models only approximate and simplify how the entities they represent work, yet models provide a powerful tool of explaining phenomena. It's critical that a model be consistent with the evidence that exists, and that different models are appropriate in different situations depending on what is being explained. If the model cannot account for the evidence, then the model should be abandoned (Schwarz et al. 2009). A Framework for K-12 Science Education states that by the end of the 12th grade students should be able to: * Construct drawings or diagrams as representations of events or systems * Represent and explain phenomena with multiple types of models and move flexibly between model types when different ones are most useful for different purposes. * Discuss the limitations and precision of a model as the representation of a system, process, or design and suggest ways in which the model might be improved to better fit available evidence or better reflect a design's specifications. Refine a model in light of empirical evidence or criticism to improve its quality and explanatory power. * Use (provided) computer simulations or simulations developed with simple simulation tools as a tool for understanding and investigating aspects of a system, particularly those not readily visible to the naked eye. * Make and use a model to test a design, or aspects of a design, and to compare the effectiveness of different design solutions. (NRC 2011, p. 3-20). What does this practice mean for classroom instruction? What does it mean that the practices of modeling will be blended with core ideas? Perhaps the biggest change the modeling practice brings to classroom teaching is the expectation for students to construct and revise models based on new evidence to predict and explain phenomena and to test solutions to various design problems in the context of learning and using core ideas. …