Systems and System Models
“[The students'] thinking about systems in terms of component parts and their interactions.... gives students a way to organize their knowledge of a system, to generate questions that can lead to enhanced understanding, to test aspects of their model of the system, and, eventually, to refine their model. ” Source: NGSS Appendix G
Introduction to Systems and System Models
Source: NGSS Appendix G
Systems and System Models are useful in science and engineering because the world is complex, so it is helpful to isolate a single system and construct a simplified model of it. “To do this, scientists and engineers imagine an artificial boundary between the system in question and everything else. They then examine 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 dioxide expelled by an organism. Consideration of flows into and out of the system is a crucial element of system design. In the laboratory or even in field research, the extent to which a system under study can be physically isolated or external conditions controlled is an important element of the design of an investigation and interpretation of results.... The properties and behavior of the whole system can be very different from those of any of its parts, and large systems may have emergent properties, such as the shape of a tree, that cannot be predicted in detail from knowledge about the components and their interactions”.
“Models can be valuable in predicting a system’s behaviors or in diagnosing problems or failures in its functioning, regardless of what type of system is being examined.... In a simple mechanical system, interactions among the parts are describable in terms of forces among them that cause changes in motion or physical stresses. 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 ecosystem) and to recognize that they all involve transfers of energy, matter, and (in some cases) information among parts of the system.... Any model of a system incorporates assumptions and approximations; the key is to be aware of what they are and how they affect the model’s reliability and precision. Predictions may be reliable but not precise or, worse, precise but not reliable; the degree of reliability and precision needed depends on the use to which the model will be put”.
Critical Questions
Source: Peter A'Hearn/ CrossCut Symbols
What are the limits of this system?
What other systems affect this system? How?
What parts and sub-systems make up this system? How do they work together?
What are the inputs and outputs of this system?
What interactions and processes involve this system?
What are the advantages to thinking about this as a system?
In what ways is this system like others I have learned about? How is it different?
Engineering- How can we improve the function of the system?
What is accurate and inaccurate about our model of this system?
How can our systems model be made more accurate?
What other crosscutting concepts apply to this system?
Based on what I've learned, what other symbol could be used to represent Systems and Systems Models?
Questions connecting to Practices
Source: Peter A'Hearn/ CrossCut Symbols
Asking Questions- How does this system work?
Defining Problems- How can I design a system to solve a problem?
Models- How can I model this system? Can we model how this system functions?
Investigations- How can we change variables to test this system?
Data- What kind of data can help us understand this system? What does the data tell us about the system?
Using Math- How can we use math to model how this system works?
Computational Thinking- How can we use computer models to understand this system?
Explanations- How can I explain the function of this system?
Solutions- Will this system solve the problem? Has the system been improved?
Argument- What evidence do we have to support our model of this system?
Information- What is already known about this system? How can I best communicate what I know about this system?
Prompts for Systems and System Models
This set of prompts is intended to help teachers elicit student understanding of crosscutting concepts in the context of investigating phenomena or solving problems. Source: STEM Teaching Tools
Learn more about Systems and System Models
Bozeman Science Video - Concept 4 - System and Systems Models
Wonder of Science Graphic Organizer: Systems and System Models - Google Draw or PDF
Webinar: Systems and System Models