Science, 2009
  Grade Level:   9-12  
  EALR 1:   Systems  
  Big Idea:   Systems (SYS)  
  Core Content:   Predictability and Feedback                   
  Description:   In prior grades students learned how to simplify and analyze complex situations by thinking about them as systems. In grades 9-12 students learn to construct more sophisticated system models, including the concept of feedback. Students are expected to determine whether or not systems analysis will be helpful in a given situation and if so, to describe the system, including subsystems, boundaries, flows, and feedbacks. The next step is to use the system as a dynamic model to predict changes. Students are also expected to recognize that even the most sophisticated models may not accurately predict how the real world functions. This deep understanding of systems and ability to use systems analysis is an essential tool both for scientific inquiry and for technological design.  
  Content Standard:   9-12 SYSA Feedback is a process in which the output of a system provides information used to regulate the operation of the system. Positive feedback increases the disturbance to a system. Negative feedback reduces the disturbance to a system.  
Students are expected to:
  • Give examples of a positive feedback system and explain its regulatory mechanism (e.g., global warming causes Earth's ice caps to melt, reflecting less energy to space, increasing temperatures).*a
  • Give examples of a negative feedback system and explain its regulatory mechanism (e.g., when a human body overheats, it produces sweat that cools the body by evaporation).*a
    Mathematics Connections
  • *a   A1.8.A   Analyze a problem situation and represent it mathematically.
          A1.1.A   Select and justify functions and equations to model and solve problems.