Technological Systems and Processes
Domain 4 - Technological Systems and Processes (title provisional). This domain covers systems thinking, control, efficiency, and the processes used to produce and maintain technological systems. Expect questions on open and closed loops, manufacturing processes, quality control, and automation.
Core rules and concepts
- A system is a set of interacting components organized toward a goal, with a boundary, environment, and interfaces.
- Open-loop control acts without feedback; closed-loop control compares sensor feedback to a setpoint and adjusts an actuator.
- Efficiency equals useful output divided by total input; losses appear as heat, waste, friction, or downtime.
- Common manufacturing processes include casting, forming, separating, conditioning, assembling, and finishing. Jigs and fixtures improve repeatability.
- CAD/CAM, CNC, and additive manufacturing connect digital models to production.
- Quality control inspects outputs; quality assurance designs the process to prevent defects. Tolerances define acceptable variation.
Worked example
A classroom hydroponic system uses a moisture sensor, controller, pump, and feedback line. If the sensor reads dry soil, the controller turns on the pump; when moisture reaches the setpoint, it stops. This is closed-loop control. If the sensor fails, the system may run open-loop or stay off, so a fail-safe rule - such as a maximum run time - matters. Explaining the feedback path and the failure mode earns more credit than naming the parts alone.
Traps that cost marks
- Calling every artifact a system without identifying components and feedback.
- Confusing a process with a product.
- Forgetting that feedback can fail or be biased.
- Miscalculating efficiency by using input/output upside down.
- Ignoring maintenance, calibration, and human operation.