SYS 4.1 Students identify and explain the logic of systems and subsystems.	SYS 4.2 Students incorporate feedback to refine and modify systems and/or subsystems.
Students know that: · systems and subsystems have logic. Students identify and explain the logic of systems and subsystems as they: · identify logic of systems and subsystems in terms of their organisation - describe the logic of components in systems and subsystems and the links between them - draw a diagram that shows the placement of components in a circuit and links between eachcomponent - draw a flowchart that illustrates the operation of subsystems in a hydroponic system - describe the logic involved in a ticketing and seating system at a school cultural evening · explain/examine the cause–effect relationships that exist between systems and subsystems - control relationships - identify and describe subsystems that help to control a system such as an on/off switch or warning mechanism - operational relationships - identify and describe how subsystems for sorting affect the operation of a recycling plant - describe the cause–effect relationship between pedals, chain and wheel on a bicycle.	Students know how: · to gather relevant feedback to refine and modify systems and/or subsystems. Students refine and modify systems and/or subsystems by incorporating feedback as they: · adjust systems/subsystems based on feedback gathered from others - refine and modify the system based on feedback from users - add a dimming device to a torch for night spotting of wildlife on a school camp after gathering information about the specific needs of the user - refine and modify systems/subsystems based on test results - carry out a field test or operational test of a solar cooker to observe the effectiveness of achieving desired outputs - test the effectiveness and accuracy of a device and make adjustments to improve its operation - consider how a system can be changed to lessen its impact on the environment or society - make comparisons between systems that carry out similar tasks to identify features that could be incorporated into a hybrid system - examine two alarm systems and select the best features of each to create new system/subsystem.
At each level, activities should occur in a range of contexts. Students should consider aspects of appropriateness and management within these activities. Examples · Students describe the logic of a hydroponic system they have designed and conduct field tests over an extended period in order to modify it. · Students design and refine an organisational system with subcommittees for ticketing, catering and seating to help coordinate a school event. · Students design and refine a system for the election of school leaders with clearly identified steps involved in the casting and counting of votes. · Students describe and refine the logic for a simple electric system for a torch.