Suggested group session: 15–20 minutes per case, adjustable for learners. Intended for roughly age 11+ with adult support when helpful. No student accounts or names are required.
Before you begin: Students should be able to multiply watts by hours and distinguish energy from power, with help available inside each investigation. Equipment values are fictional and cases do not replace electrical safety advice.
Investigation worksheet
1. The Overnight Drain
Objective: Keep the refrigerator running for the full 18:00–06:00 night.
Prediction: What do you think caused the problem? _______________________________________
Evidence: Write down two readings and their units. _______________________________________
Test: What single intervention did you select, and what changed? ______________________________
Explanation: Describe what the evidence proves and why the task succeeded or failed. ____________
Transfer: A replacement inverter draws 10 W of overhead for 24 hours. How much energy does overhead alone use?
2. Full Battery, Cold Kettle
Objective: Deliver 75 Wh of kettle heating within five minutes while retaining 100 W background service.
Prediction: What do you think caused the problem? _______________________________________
Evidence: Write down two readings and their units. _______________________________________
Test: What single intervention did you select, and what changed? ______________________________
Explanation: Describe what the evidence proves and why the task succeeded or failed. ____________
Transfer: Will the 900 W kettle fit if the background load rises from 100 W to 200 W?
3. The Misleading Battery Label
Objective: Supply 120 W of AC cabin service for 12 hours using a compatible battery/inverter preset.
Prediction: What do you think caused the problem? _______________________________________
Evidence: Write down two readings and their units. _______________________________________
Test: What single intervention did you select, and what changed? ______________________________
Explanation: Describe what the evidence proves and why the task succeeded or failed. ____________
Transfer: How do 25.6 V × 100 Ah and 12.8 V × 200 Ah compare?
Facilitator notes — do not print with learner worksheet
Let learners make initial guesses. Ask for an actual measurement boundary and a controlled before/after comparison; do not reveal the expected diagnosis before they run the system.
Facilitator workflow: learners select a supporting experiment separately from the run they are currently inspecting. They should connect a model-true service-preserving intervention to the original evidence, then check the explanation. Transfer feedback appears only after submitting an answer. A case-explained status remains even if the learner later inspects an unsuccessful experiment. Replay shows the stored run at a shared scenario-relative time; the numerical table is equally authoritative.
Local progress: progress is browser-specific. Version-1 completed records can be migrated only where there is sufficient original evidence and an actual submitted correct answer; partially lost old awards cannot safely be invented. Clearing Detective progress never clears Renewable Energy City data. Saved progress from the newer format will not be visible if an old deployment is temporarily restored.
- Overnight Drain: 45 W / 0.9 + 50 W = 100 W battery draw. 1,000 Wh lasts 10 h, ending 04:00. The 10 W low-idle inverter draws 60 W and leaves 280 Wh. Transfer: 240 Wh.
- Cold Kettle: 1,500 + 100 = 1,600 W exceeds 1,000 W continuous AC. A 2,000 W inverter or 900 W for five minutes can meet the 75 Wh target; merely doubling storage cannot. Transfer: 1,100 W is still too high.
- Battery Label: A: 12.8 × 100 × 0.8 = 1,024 Wh; B: 25.6 × 100 × 0.8 = 2,048 Wh. A lasts 7.68 h and B can serve the full 12 h. Transfer: 12.8 V × 200 Ah stores the same nominal energy as 25.6 V × 100 Ah.
Check for the distinction between watts and watt-hours. The provided score is a learning prompt, not a standardized assessment. Observe without collecting names or recordings.