# Week 2 integrated guide — energy systems and model limits **Version:** v0.1, 29 September 2026. **Five 35-minute paper-only Science sessions.** Draft for educator, science, accessibility and local-syllabus review. Students build and challenge an original [A4 energy-flow diagram](energy-flow.svg) ([PNG](energy-flow.png)) with a [complete plain-text alternative](#plain-text-energy-flow-and-original-learner-card). The numbers are **invented** for a simplified steady model over one interval; no physical lamp was measured. This block assesses scientific energy accounting and claim validity, not the day's mathematics or English mark. **National links:** AC9S9U05 addresses conservation of energy and efficiency as inputs, outputs, transfers and transformations. AC9S9I04 concerns representations; AC9S9I05 patterns/anomalies; AC9S9I06 validity/uncertainty; AC9S9I07 evidence-based arguments. These are **partial** exact Year 9 content descriptions in the [official ACARA v9 download](https://www.australiancurriculum.edu.au/downloads), retrieved 29 September 2026; workbook SHA-256 `db446882d2c00cf7c085a03e250e2442fda6c44011fc114680c46c1dc7a822c3`. [OpenStax College Physics 2e, section 7.6](https://openstax.org/books/college-physics-2e/pages/7-6-conservation-of-energy) states that energy is conserved while changing form/transferring, and defines efficiency as useful output divided by total input. It supports the principle and calculation, not our fictional values or any device claim. **Safety and access:** Paper cards only. No mains devices, exposed wiring, hot lamps, lasers, battery dismantling or direct sunlight. Print the diagram or use its exact text, high contrast, raised/large arrows, screen reader, tactile counters, keyboard, AAC, sign or learner-directed adult placement. A student can critique the model without drawing an arrow. The 100 J input in this illustration is an invented energy amount over a stipulated interval, not 100 W or a real specification. The model assumes no energy is stored in the chosen system during that interval; otherwise input minus output could be stored. `Other transfer` is not energy destroyed and is not necessarily only heat in every real device. ## Day 1 — Define the system before adding numbers **Question:** What enters, leaves or stays in a model system? **35 = 5 notice + 7 model + 12 build + 8 audit + 3 check.** 1. **Notice, 5:** Show paper box labelled fictional model lamp. Ask “What is the system boundary?” **Key:** the drawn box around lamp for one stipulated interval, not the whole room. 2. **Model, 7:** Teacher places `electrical input 100 J` arrow into box, `useful light 60 J` and `other transfer 40 J` arrows out. “In this simplified steady model, 100 in = 60 + 40 out; none disappears.” Name light/thermal as possible forms without claiming a measured lamp. 3. **Build, 12:** Learners arrange 10-J paper tiles in 10/6/4 groups or use text/tactile counts. Draw or dictate arrows with units and boundary. Explain why both output arrows count. 4. **Audit, 8:** Present flawed diagram `100 in → 60 useful` with no other arrow. Ask what is unaccounted for. **Key:** 40 J; one cannot say it vanished. Add `other transfer 40 J` or explicitly name possible storage if model changes. 5. **Check, 3:** “Is 40 J destroyed?” **Key:** no, transferred/transformed outside the useful category. **Next:** rebuild balance with all arrows. ## Day 2 — Useful depends on the stated purpose **Question:** What counts as useful output for a chosen task? **35 = 5 retrieve + 7 model + 12 sort + 8 explain + 3 check.** 1. **Retrieve, 5:** Point to input, useful and other arrows. Verify 60+40=100 and J versus W distinction: joule is energy; do not call the 100 J arrow “100 watts”. 2. **Model, 7:** “For our model lamp's lighting task, light is named useful and the other transfer is not the target. For a fictional food warmer, thermal output could be useful. `Useful` is purpose-dependent; energy is still conserved.” No real efficiency figures supplied. 3. **Sort, 12:** Learners classify **qualitative** cards for a stage lamp, phone speaker, model bike generator and food warmer: desired output, possible other transfer, what would require a measurement. Do not score a specific numeric transfer from these cards. 4. **Explain, 8:** Pairs choose one device and state a system boundary, intended output and an unknown. Ask whether a different purpose would change the useful label but not the conservation rule. 5. **Check, 3:** “If we call thermal energy useful for a heater, did we create extra energy?” **Key:** no; classification changes, accounting remains. **Next:** revisit purpose before percentages. ## Day 3 — Calculate efficiency and keep units honest **Question:** What share of input becomes the stipulated useful output? **35 = 5 recall + 7 model + 12 calculate + 8 compare + 3 check.** 1. **Recall, 5:** Read 100 J in, 60 J useful, 40 J other. **Key:** totals balance. 2. **Model, 7:** “Efficiency for this purpose = useful output/input ×100 = 60/100×100 = **60%**. Both numerator and denominator are J over the same model interval, so the ratio has no unit.” A percentage is not a brightness measurement. 3. **Calculate, 12:** New fictional same-purpose model B has 100 J input, 75 J useful light, 25 J other transfer. **Key:** 75%; 75+25=100. Learners use tiles, fraction bar or calculator and identify what stays comparable. 4. **Compare, 8:** “B has a higher **modelled useful-energy fraction** than A under these stated conditions.” Do **not** claim B is brighter, cheaper, safer, longer-lasting or a real product. Ask what real performance data and time window would be needed. 5. **Check, 3:** “Can an 80 J useful output come from 60 J total input in our steady box without another source?” **Key:** no. **Next:** inspect system boundary and omitted input/storage before trusting a figure. ## Day 4 — Audit claims, assumptions and uncertainty **Question:** Which sentence follows from a paper model and which outruns it? **35 = 5 identify + 7 model + 12 audit + 8 revise + 3 check.** 1. **Identify, 5:** Read fictional caption: “Model A has no energy transfer beyond light.” **Key:** contradicted by 40 J other arrow. 2. **Model, 7:** Teacher revises: “This paper model assigns 60% of A's 100 J input to useful light over the chosen interval; 40 J is assigned to other transfer. It does not measure a real lamp.” Name assumption of no stored energy and same boundary. 3. **Audit, 12:** Sort claims: `A totals 100 J output` supported; `A is 60% efficient for stated purpose` supported; `B is better for all uses` unsupported; `40 J disappears` contradicted. For each, cite an arrow or missing measurement. 4. **Revise, 8:** Learners write/point/dictate a fair claim for a modelled bike generator or phone speaker **without inventing values**, then list one measurement needed before quantifying it. 5. **Check, 3:** “Why can a 60% label not prove actual room lighting performance?” **Key:** fictional energy amounts, no real device/interval/measurement/conditions; useful fraction is a narrower construct. **Next:** label source status before conclusion. ## Day 5 — Fresh model and an evidence-based argument **Question:** Can a learner account for energy and critique a new model independently? **35 = 5 plan + 7 model + 12 unseen task + 8 peer check + 3 exit.** 1. **Plan, 5:** Review success criteria, not new answers: boundary/interval, input/output balance, useful fraction, one defensible claim and one limit. 2. **Model, 7:** Use **unscored** 50 J input, 20 J useful and 30 J other. **Key:** 40% useful; conservation 20+30=50. Show what an explanation looks like. 3. **Unseen task, 12:** Give Model C: 250 J in, 175 J useful, 75 J other; Model D: 250 J in, 200 J useful, 50 J other, same stated task/interval. Learner makes text, tactile, diagram or AAC response. **Teacher keys:** both balance 250; C=70%, D=80%; D has higher modelled useful fraction by 10 percentage points. No real lamp conclusion. 4. **Peer check, 8:** Partner checks totals and source label, then challenges “D is always the best real lamp”. **Key response:** our fictional same-purpose figures do not establish real performance, quality, suitability or cost. Learner revises one claim. 5. **Exit, 3:** “If our box stored 20 J during the interval, what would change?” **Key:** outputs need total input minus 20 J (or explicit stored-energy term); do not force 100% into outgoing arrows. **Next:** reteach boundary/storage if learner says energy vanishes. ## Plain-text energy flow and original learner card ```text FICTIONAL MODEL A, ONE INTERVAL, NO STORAGE 60 J useful light ─────► 100 J input ───► [MODEL LAMP] 40 J other transfer ───► Balance: 100 J in = 60 J + 40 J out. Useful fraction = 60/100 = 60% for the stated lighting task. This is NOT a measurement of any real lamp. MY SYSTEM BOUNDARY/INTERVAL: ____________________________ INPUT(S): __________ USEFUL OUTPUT: ___________________ OTHER TRANSFER(S) OR STORAGE: __________________________ BALANCE: ________ USEFUL FRACTION: _____________________ WHAT THE MODEL SUPPORTS: _______________________________ ONE REAL-WORLD CLAIM IT CANNOT SUPPORT: ________________ RESPONSE ROUTE / CONTENT CUE: __________________________ ``` **Formative scoring:** Award 0 = not yet with access, 1 = after scientific content cue, 2 = independent for each of four criteria: correct boundary/energy balance, correct fraction for stated purpose, evidence-linked claim, stated model limit. /8 selects instruction, not Year 9 attainment. If balance weak, retile input/output with storage term; if fraction weak, align units and divide useful by total; if claim weak, point to a labelled arrow; if limit weak, distinguish invented model from measured device. Fresh recheck outside lessons: fictional steady Model E has 180 J input, 126 J useful and 54 J other; **key:** balances, 70%; no measured device claim. Keep records private. **Rights:** Original guide/model/diagram © NeuroForgeIO Pty Ltd 2026, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). Credit *SubjectNest Year 9 Australian-first opening pack*, v0.1, [source](https://github.com/neuroforge-io/neuroforge_business/tree/main/products/curriculum-studio/content/year-9/term-1), licence and changes. ACARA/OpenStax have separate terms; no third-party figure or data is reproduced. [Integrated-file hashes](manifest.sha256). Science/educator review pending.