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Introduction to SEP2: Developing and Using Models

from NGSS Appendix F: Science and Engineering Practices in the NGSS

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 representing forces on a particular object in a system. (NRC Framework, 2012, p. 58)

Models include diagrams, physical replicas, mathematical representations, analogies, and computer simulations. Although models do not correspond exactly to the real world, they bring certain features into focus while obscuring others. All models contain approximations and assumptions that limit the range of validity and predictive power, so it is important for students to recognize their limitations.

In science, models are used to represent a system (or parts of a system) under study, to aid in the development of questions and explanations, to generate data that can be used to make predictions, and to communicate ideas to others. Students can be expected to evaluate and refine models through an iterative cycle of comparing their predictions with the real world and then adjusting them to gain insights into the phenomenon being modeled. As such, models are based upon evidence. When new evidence is uncovered that the models can’t explain, models are modified.

In engineering, models may be used to analyze a system to see where or under what conditions flaws might develop, or to test possible solutions to a problem. Models can also be used to visualize and refine a design, to communicate a design’s features to others, and as prototypes for testing design performance.

Distinguishing Practices In Science from Those In Engineering

from A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (page 50)

2. Developing and Using Models
Science often involves the construction and use of a wide variety of models and simulations to help develop explanations about natural phenomena. Models make it possible to go beyond observables and imagine a world not yet seen. Models enable predictions of the form “if . . . then . . . therefore” to be made in order to test hypothetical explanations.  Engineering makes use of models and simulations to analyze existing systems so as to see where flaws might occur or to test possible solutions to a newproblem. Engineers also call on models of various sorts to test proposed systems and to recognize the strengths and limitations of their designs.

K-12 Progressions

from NGSS Appendix F: Science and Engineering Practices in the NGSS

K-2 3-5 6-8 9-12

Developing and Using Models

A practice of both science and engineering is to use and construct models as helpful tools for representing ideas and explanations. These tools include diagrams, drawings, physical replicas, mathematical representations, analogies, and computer simulations. Modeling tools are used to develop questions, predictions and explanations; analyze and identify flaws in systems; and communicate ideas. Models are used to build and revise scientific explanations and proposed engineered systems. Measurements and observations are used to revise models and designs.

Modeling in K–2 builds on prior experiences and progresses to include using and developing models (i.e., diagram, drawing, physical replica, diorama, dramatization, or storyboard) that represent concrete events or design solutions.

Modeling in 3–5 builds on K–2 experiences and progresses to building and revising simple models and using models to represent events and design solutions.

Modeling in 6–8 builds on K–5 experiences and progresses to developing, using, and revising models to describe, test, and predict more abstract phenomena and design systems.

Modeling in 9-12 builds on K-8 experiences and progresses to using, synthesizing, and developing models to predict and show relationships among variables between systems and their components in the natural and designed world(s).

Distinguish between a model and the actual object, process, and/or events the model represents.

Compare models to identify common features and differences.
Identify limitations of models.

Evaluate limitations of a model for a proposed object or tool. Evaluate merits and limitations of two different models of the same proposed tool, process, mechanism, or system in order to select or revise a model that best fits the evidence or design criteria.

Design a test of a model to ascertain its reliability
Develop and/or use a model to represent amounts, relationships, relative scales (bigger, smaller), and/or patterns in the natural and designed world(s).
Collaboratively develop and/or revise a model based on evidence that shows the relationships among variables for frequent and regular occurring events.

Develop a model using an analogy, example, or abstract representation to describe a scientific principle or design solution.

Develop and/or use models to describe and/or predict phenomena.
Develop or modify a model—based on evidence – to match what happens if a variable or component of a system is changed.

Use and/or develop a model of simple systems with uncertain and less predictable factors.

Develop and/or revise a model to show the relationships among variables, including those that are not observable but predict observable phenomena.
Develop, revise, and/or use a model based on evidence to illustrate and/or predict the relationships between systems or between components of a system.

Develop and/or use multiple types of models to provide mechanistic accounts and/or predict phenomena, and move flexibly between model types based on merits and limitations.
Develop a simple model based on evidence to represent a proposed object or tool.
Develop a diagram or simple physical prototype to convey a proposed object, tool, or process.

Use a model to test cause and effect relationships or interactions concerning the functioning of a natural or designed system.
Develop and/or use a model to generate data to test ideas about phenomena in natural or designed systems, including those representing inputs and outputs, and those at unobservable scales.
Develop a complex model that allows for manipulation and testing of a proposed process or system.

Develop and/or use a model (including mathematical and computational) to generate data to support explanations, predict phenomena, analyze systems, and/or solve problems.

Goals for SEP2: Developing and Using Models

from A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (page 58)

By grade 12, students should be able to

• Construct drawings or diagrams as representations of events or systems—for example, draw a picture of an insect with labeled features, represent what happens to the water in a puddle as it is warmed by the sun, or represent a simple physical model of a real-world object and use it as the basis of an explanation or to make predictions about how the system will behave in specified circumstances.
• Represent and explain phenomena with multiple types of models—for example, represent molecules with 3-D models or with bond diagrams—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.

Performance Expectations Associated with SEP2: Developing and Using Models

K-2 3-5 6-8 9-12

A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (pages 56-59)

Science Practices Continuum - Students' Performance
This tool is a continuum for each practice that shows how students' performance can progress over time. A teacher can use the continuum to assess students' abilities to engage in the practices and to inform future instruction. From Instructional Leadership for Science Practices.

Science Practices Continuum - Supervision
This tool is a continuum for each practice that shows how instruction can progress over time. An instructional supervisor can use the continuum to identify the current level for a practice in a science lesson. Then the supervisor can provide feedback, such as offering instructional strategies to help move future instruction farther along the continuum. From Instructional Leadership for Science Practices.

Potential Instructional Strategies for Developing and Using Models
This instructional strategies document provide examples of strategies that teachers can use to support the science practice. Supervisors might share these strategies with teachers as they work on improving instruction of the science practices. Teachers might find these helpful for lesson planning and implementing science practices in their classrooms. From Instructional Leadership for Science Practices.

Bozemanscience Video