Systems and Diagrams Notes

Systems Diagrams
  • Systems diagrams use boxes to represent stores (where matter/energy accumulate) and arrows to represent flows (movement of matter/energy).
  • The system boundary outlines the entire system, separating it from its surroundings.
  • Inputs are matter/energy entering the system from outside (arrows inward across boundary).
  • Outputs are matter/energy leaving the system to the outside (arrows outward across boundary).
Open versus Closed Systems
  • Open System: Exchanges both energy and matter across its system boundary with its surroundings.
    • Example: A pond, which exchanges water, nutrients, and heat.
  • Closed System: Exchanges only energy (not matter) across its system boundary with its surroundings.
    • Example: Planet Earth's nutrient cycles (e.g., carbon cycle), where carbon stays within the Earth ecosystem, but solar energy enters and heat energy leaves.
Transfers versus Transformations
  • Transfer: Involves matter or energy moving from one place to another without changing its state, chemical nature, or form.
    • Example: An animal eating a plant, where chemical energy moves from plant to animal.
  • Transformation: Involves a change in the chemical nature, state, or form of matter or energy.
    • Examples: Photosynthesis (light energy <br/>ightarrow<br /> ightarrow chemical energy), Evaporation (liquid water <br/>ightarrow<br /> ightarrow water vapor gas).