systems approach to designing
4 detailed 50-minute lessons with teaching scripts, worked examples, parent guides, and assessment criteria.
4 detailed 50-minute lessons with teaching scripts, worked examples, parent guides, and assessment criteria.

Write down everything you already know about systems approach to designing. Then check against the key terms: D&T Exam Tips. Use a mini-whiteboard or paper.
Start with the revision notes summary, then attempt: Explain the difference between an open-loop and a closed-loop system, giving an example of each.
Your student states one thing they learned and one question they still have about systems approach to designing.
Quick recap: write 3 key points from Lesson 1 on systems approach to designing. Check them against the notes below.
| Term | Meaning | Example |
|---|---|---|
| Open-loop | None | Timer-based watering |
| Closed-loop | Negative | Central heating thermostat |
| Bang-bang | On/off | Oven thermostat |
| Proportional | Continuous | Industrial temperature control |
| Microcontroller | Programmable | BBC Micro:bit projects |
| PLC | Industrial | UK food packaging lines |
Q: Explain the difference between an open-loop and a closed-loop system, giving an example of each.
Answer: Open-loop: no feedback — the system does not monitor its own output. E.g. a fan heater with a simple on/off switch runs at fixed power. Closed-loop: feedback adjusts the output. E.g. a fan heater with a thermostat senses room temperature and adjusts power to maintain the desired temperature.
Your student teaches the key points back to you without looking. Fill any gaps immediately.
Recall the key terms: D&T Exam Tips. Define each in one sentence.
Q1: Explain the difference between an open-loop and a closed-loop system, giving an example of each.
Answer: Open-loop: no feedback — the system does not monitor its own output. E.g. a fan heater with a simple on/off switch runs at fixed power. Closed-loop: feedback adjusts the output. E.g. a fan heater with a thermostat senses room temperature and adjusts power to maintain the desired temperature.
Q2: A washing machine uses sensors to detect load weight and water temperature. Draw a systems diagram and explain how feedback is used.
Answer: Input: load sensor, temperature sensor, water level sensor. Process: microcontroller compares sensor data with programmed settings. Output: motor speed, water valve, heater control. Feedback: temperature sensor feeds back actual water temperature; microcontroller adjusts heater to reach target. Load sensor determines cycle time — heavier loads need longer.
Q3: Why is a closed-loop system more suitable than an open-loop system for controlling a greenhouse irrigation system?
Answer: A greenhouse needs precise moisture levels: too little water kills plants, too much causes root rot. Closed-loop: soil moisture sensor provides feedback, microcontroller activates irrigation only when moisture drops below threshold. Open-loop: timer-based watering regardless of soil conditions — wastes water in rain, underwater in drought. Closed-loop is essential where conditions vary.
Review any questions answered incorrectly. Identify whether the error was knowledge, method, or reading the question.
Review what these command words require: state (one point), describe (say what happens), explain (say why), compare (both sides), evaluate (judgement).
Extended question: Full-Mark Response Design a closed-loop system for an automatic greenhouse ventilation system. Explain the input, process, output and feedback, and justify why a closed-loop approach is necessary. <div class="
A grade 9 response will: define input (temperature sensor and humidity sensor inside greenhouse), process (microcontroller compares readings with set points — e.g. 25°C and 60% RH), output (motor opens roof vents, fan activates), feedback (continuous sensor monitoring — when temperature drops below set point, vents close, fan stops); explain why closed-loop is needed (external temperature fluctuates, solar gain varies, open-loop timer cannot respond to actual conditions); discuss safety features (vent limit switches, alarm for sensor failure) and energy efficiency (vents use natural convection before activating fans).
You are ready for systems approach to designing - GCSE Design and Technology Lessons when you can:
Tick each item honestly — if any box is unticked, re-read the relevant section above.
How examiners mark systems approach to designing - GCSE Design and Technology Lessons: Read the command word carefully — State = one word/phrase (1 mark), Describe = pattern or detail (2 marks), Explain = reason with "because" (2–3 marks), Compare = similarities AND differences, Evaluate = both sides + conclusion. Method marks are awarded for correct working even if the final answer is wrong. Always show your working — unexplained answers score zero for AO2.
Success on systems approach to designing - GCSE Design and Technology Lessons questions: Underline the command word, count the marks (one mark per point expected), and answer in the format the command word demands.
This lesson is examined by: AQA 8552 | Edexcel 1DT0 | OCR J310 | Eduqas comps | CCEA units. Tier and paper details vary - always check your board's current specification.
Follow-up revision: DT4-systems-approach-to-designing on GCSE Revise (notes, flashcards and auto-graded target tests for this exact topic).