Systems and System Models
A system is a group of parts that work together as a unified whole. Examples can be complex like a car or the human body or very simple like a pencil. In order to understand how a particular system works, scientists and engineers make system models. A boundary is drawn around the system being studied and they keep careful track of:
- forces acting on it
- energy flowing in or out of it
- matter flowing in or out of it
Through very careful accounting they can see that the system consumes, what it produces, what its stores, and what effects it causes.
Universal Systems Model: Models can be used to represent systems and their interactions—such as inputs, processes and outputs—and energy and matter flows within systems.
Systems are defined by inputs, processes, outputs, and feedback. Processes are activities that happen inside the system. The inputs to a system can be either matter or energy. Processes change these to produce the outputs. Feedback can be matter, energy, or information that flows back from the output and modifies the input. By keeping careful track of these four components, it is possible to understand many technological and natural systems..
Systems may interact with other systems; they may have sub-systems and be a part of larger complex systems.
Whether it is a car, the human body, or our planet, complex systems are composed of many interacting subsystems. By breaking things down into their subsystems it is of ten easier to study and understand their function.
Models are limited in that they only represent certain aspects of the system under study.
Complex systems are hard to model. Scientists begin with the most important aspects and develop more complex models over time. Models may not be able to include every details about a system, but science has been successful at building very useful ones that make accurate predictions.