Parent plan · Week 25 · Work & Machines — apply and extend — Physical Science: Matter, Forces & Energy
Parent teaching plan · 36 weeksUnits to teach or revisit
Chapter 6 · Work & Machines
Assigned readings
Chapter 6 continues one explanation across five smaller units. Questions from the launch should remain active as new evidence is added.
This week’s goals
- Explain the assigned questions using named mechanisms and relevant records.
- Read the labeled figures and distinguish observations from inferences.
- Revise an explanation after checking its evidence and assumptions.
Read the chapter launch and assigned unit sections on their linked lesson pages. Keep the launch model and return to it after each new evidence comparison.
Five flexible sessions of about 40–45 minutes. Formal papers may join consecutive sessions; take the stated total exam time. Slow down and replace a flex task with reteaching when evidence of understanding is incomplete.
Session 1 · Efficiency & Improving a Design — connect and test
Identify where energy transfers away from the intended output. Friction, deformation, heating of components, and noise can matter in a mechanical device. A redesign should target a measured mechanism while respecting constraints such as stability and cost. Reducing one loss can introduce a new problem.
Your task
Study Parts 3–4. Answer both checkpoints and the figure question, then work the whole-unit application with intermediate steps. Use the labeled figures and “Read the visual model” question in the assigned part; explain an attempted answer before opening guidance.
- Read Parts 3–4 in manageable sections.
- Name the graph axes, quantities or receivers in the figure.
- Attempt the application before reading its model.
- Check reasoning, units and the case assumptions.
Hint and response guidance
Use the assigned unit’s figures, captions and worked examples. Identify conditions and units before choosing a relationship.
A design must also meet safety, reliability, cost, and other requirements. An efficiency improvement can create an unacceptable trade-off. Best trials can reflect random variation or favorable conditions. Comparable repeated results provide a more representative performance comparison.
- Use the supplied observations and measurements accurately; include units where needed.
- Explain the science behind your answer, rather than giving only a number or label.
- Show a labeled model, calculation, or evidence comparison as requested.
- State an assumption or limitation and suggest a useful next measurement.
Session 2 · Efficiency & Improving a Design — practise and revise
Illustrative machine A receives 250 J and delivers 150 J useful output; B receives 200 J and delivers 150 J. Their task and measurement boundary match.
Your task
Study the worked examples, complete the unit practice and retrieval questions, then return to the phenomenon and explain the model change. Complete the exit check; use the sustained tasks for additional depth or a needed correction. Use the labeled figures and “Read the visual model” question in the assigned part; explain an attempted answer before opening guidance. Complete the new illustrated practice and independent visual-transfer case for this unit.
- Explain a worked example with the answer covered.
- Attempt independent questions and record reasoning.
- Use feedback to correct a specific error.
- Revise the initial model and answer the exit check without notes.
Hint and response guidance
Use the assigned unit’s figures, captions and worked examples. Identify conditions and units before choosing a relationship.
A is 60% efficient and B 75% for the stated task. The remaining modeled outputs are 100 J and 50 J in other pathways, such as thermal changes or sound. These amounts are not destroyed. An output called waste for lifting might be useful for heating, so usefulness must be defined before comparing fractions.
- Use the supplied evidence.
- Explain a mechanism or calculation.
- Correct rather than erase an error.
- Identify a limit or remaining question.
Session 3 · Power: The Rate of Energy Transfer — observe and build
Illustrative evidence case. Illustrative lifting devices each deliver 240 J; A takes 8 s and B 12 s. A receives 400 J and B receives 300 J. The unit’s visible language notes define the scientific words before the main reading.
Your task
Make the first model, read the core explanation and Parts 1–2, then answer their reasoning checks. Describe the associated figure using labels and caption. Use the labeled figures and “Read the visual model” question in the assigned part; explain an attempted answer before opening guidance.
- List two observations and one question.
- Sketch an initial explanation before opening guidance.
- Read the language notes and explain Parts 1–2 in plain words.
- Attempt both checkpoints; discuss and revise.
Hint and response guidance
Use the assigned unit’s figures, captions and worked examples. Identify conditions and units before choosing a relationship.
No. It transfers the same stated 120 J over a longer interval, so its average power is smaller. The input energy or input power and the losses. Useful lifting power alone does not describe all energy entering the device.
- Keep observations distinct from causes.
- Use the defined terms correctly.
- Connect the model to stated evidence.
Session 4 · Power: The Rate of Energy Transfer — connect and test
Efficiency is the fraction of input energy reaching the chosen useful output. Power and efficiency describe different things: a high-power device can have high or low efficiency. Compare input and output over the same interval and define usefulness.
Your task
Study Parts 3–4. Answer both checkpoints and the figure question, then work the whole-unit application with intermediate steps. Use the labeled figures and “Read the visual model” question in the assigned part; explain an attempted answer before opening guidance.
- Read Parts 3–4 in manageable sections.
- Name the graph axes, quantities or receivers in the figure.
- Attempt the application before reading its model.
- Check reasoning, units and the case assumptions.
Hint and response guidance
Use the assigned unit’s figures, captions and worked examples. Identify conditions and units before choosing a relationship.
No. Efficiency is a ratio. The power also depends on the energy amount and time interval. The operating duration, actual average power, cycling and energy price are also needed. A rating describes a condition rather than every day’s use.
- Use the specified quantities and units.
- Explain an intermediate step or comparison.
- Connect the pattern to the physical mechanism.
- State an assumption or limitation.
Session 5 · Power: The Rate of Energy Transfer — practise and revise
Illustrative lifting devices each deliver 240 J; A takes 8 s and B 12 s. A receives 400 J and B receives 300 J.
Your task
Study the worked examples, complete the unit practice and retrieval questions, then return to the phenomenon and explain the model change. Complete the exit check; use the sustained tasks for additional depth or a needed correction. Use the labeled figures and “Read the visual model” question in the assigned part; explain an attempted answer before opening guidance. Complete the new illustrated practice and independent visual-transfer case for this unit.
- Explain a worked example with the answer covered.
- Attempt independent questions and record reasoning.
- Use feedback to correct a specific error.
- Revise the initial model and answer the exit check without notes.
Hint and response guidance
Use the assigned unit’s figures, captions and worked examples. Identify conditions and units before choosing a relationship.
Useful powers are 30 W for A and 20 W for B. Efficiencies are 240/400=60% and 240/300=80%. A delivers useful energy faster but B directs a larger fraction of input to that output. Power and efficiency answer different questions, and both require the same defined useful output.
- Use the supplied evidence.
- Explain a mechanism or calculation.
- Correct rather than erase an error.
- Identify a limit or remaining question.
Submit this week
- Dated notebook entries and the assigned evidence or graph work.
- An attempted model, revised model and the evidence behind the change.
- Practice corrections or a human-reviewed assessment, as assigned.
Parent / teacher weekly conference
Start with the learner’s own explanation. Ask which record supports each claim, and which condition could change it. Check units, graph axes and model limits. Use supplied data without claiming it was experimentally measured at home. An oral explanation or accessible drawing can substitute for extended prose when it shows the same reasoning.
- Can the learner explain the core mechanism without copying?
- Can they read the new figure and identify a limit?
- Which error needs a different explanation or worked example next session?