Topic 1: Systems and Models Flashcards
Outline the concept and characteristics of systems
Systems can be viewed seperately or holistically. Systems contain: Storages, flows, processes, feedback mechanisms that maintain stability and equilibrium.
Define an; Open system, closed system and isolated system
Open system: A system which exchanges matter and energy with its surroundings
Closed system: A system which exchanges energy but not matter with its surroundings
Isolated system: A system which doesn’t share its matter or energy with its surroundings
What are the first two laws of Thermodynamics, and what is there relevance to environmental systems?
First Law of Thermodynamics: Energy can neither be created nor destroyed. Total energy in a system is constant, only changes forms.
Second law of Thermodynamics: Energy goes from a concentrated form into a dispersed one - work diminishes energy the higher up in a system it is
Explain the nature of equilibria
The state of equilibrium means that despite slight fluctuation in the systems, there are no sudden changes and the fluctuations are closely within limits
Define and explain the principles of Positive and Negative Feedback
Positive feedback - Occurs when a change in the state of a system leads to additional and increased change.
Negative feedback - Is the reduction of effects of one of the systems components.
Describe transfer and transformation processes
Transfer: Movement of energy without change of form
Transformation: Movement of energy with change in state
List advantages and disadvantages to models
Advantages:
- Allow scientists to predict and simplify complex systems
- Inputs can be changed and outcomes examined without having to wait for real events
- Results can be shown to other scientists and to the public
Disadvantages:
- They may not be accurate
- They rely on the expertise of the people making them
- Different people may interpret them in different ways
