Master "plan an experiment" questions for A-Level practicals
Download printable cheat-sheet (CC-BY 4.0)26 Jul 2025, 00:00 Z
Are you flustered when you flip your practical paper and see a question on "Plan an experiment" page?
TL;DR
"Planning an experiment" questions compress a week-long research cycle into 75 anxious minutes.
These high-mark questions expect novices to think creatively and technically and provide almost no scaffolding. Yet, with the right support, they are a uniquely powerful way to cultivate authentic scientific reasoning.
1. The planning-question conundrum
1a. What exactly is being assessed?
In Cambridge AS/A-Level Physics Paper 5, Question 1 alone is worth 15 marks and requires candidates to propose apparatus, method, analysis and evaluation from scratch'.
1b. Why it feels brutally hard
| Pain-point | How it bites |
| Cognitive-load overload | Students must juggle equipment choice, variable control, measurement precision and error analysis simultaneously — a textbook recipe for split-attention overload'. |
| Performance anxiety | More than half of secondary-school science students report heightened anxiety during practical exams'. |
| Novice-expert gap | Teachers themselves cite uncertainty about “correct answers” and time costs as barriers to running open-ended labs'. |
| Exam culture | High-stakes grading is argued to encourage “cook-book” labs and may discourage risk-taking, although direct causal evidence for A-level contexts is limited'. |
2. Why keep planning questions at all?
Open-ended practicals mirror real research, obliging learners to articulate hypotheses, design experimental variables and critique their own methods.
These skills are also championed by professional bodies such as the UK Institute of Physics, which calls for more “real-life” physics in schools'.
3. Case study: the paper-helicopter investigation
The paper-helicopter investigation is a common experimental scenario to determine how rotor-blade width \(w\) affects terminal velocity \(v\) of a paper helicopter.
Key components include purpose, controlled variables, data-collection loop, uncertainty analysis and suggested improvements.
Class-friendly variants of this task abound — from STEM blogs that use helicopters to teach cause-and-effect to George Box's classic DOE exercise for engineers.
4. How teachers can lower the barrier without “giving the answer”
- Worked-example → faded-example pairs. Show one fully annotated plan, then a template with key steps blanked; this demonstrably reduces extraneous load.
- Teach the “PEAR” heuristic. Purpose → Equipment → Actions → Reliability gives novices a four-box checklist that externalises the design cycle.
- Micro-design sprints. 15-minute challenges (“optimise flight-time using blade length”) build fluency before the high-stakes exam.
- Make uncertainty visible. Compare hand-timed drops (±0.2 s reaction-time uncertainty) with light-gate timing to illustrate why electronic methods shrink errors by an order of magnitude.
- Reframe 'creativity'. Use paper-helicopter factorial designs to show that systematic variation, not random guessing, drives optimisation.
5. Tactical playbook for students
- Memorise a generic skeleton (Aim → Diagram → Table → Analysis); having a template frees cognitive bandwidth for thinking.
- Chunk variable control: list all factors, tick those held constant, star the one varied.
- Quote uncertainties honestly: if you hand-time, use ±0.20 s; don't pretend to millisecond precision'.
- Sketch the graph before collecting data; deciding axes and gradients early guarantees you harvest the right numbers.
- Practise under timed conditions: rehearsal under exam-style timing consistently lowers anxiety; many students report noticeable improvements after several full run-throughs'.
6. Conclusion
Students dislike planning questions not because they are pointless, but because the gap between day-to-day “recipe” labs and exam-day open inquiry is still too wide.
By embedding scaffolded paper-helicopter tasks, explicit design heuristics and honest conversations about uncertainty, educators can shrink that gap.
For learners, reframing the blank page as a game of controlled experimentation turns dread into design confidence.
