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P5.Planning, Analysis & Evaluation

Higher-Order Practical SkillsA Level

Chapter 1: Paper 5 Question 1 Planning

P5.1.1 What Q1 Tests and How Marks Are Earned

Syllabus-locked interpretation

In Paper 5, Question 1 is a planning question worth 15 marks. The response is not a short one-line method. It is an extended, structured design showing that your experiment is workable and can generate data for a valid conclusion.

Four skill blocks tested in Q1

  • 1. Defining the problem (independent, dependent, controls).
  • 2. Methods of data collection (apparatus + measurements).
  • 3. Method of analysis (derived quantities + graph choice).
  • 4. Additional detail including safety precautions.

Exam reality:

A response that looks \"scientific\" but does not specify measurable quantities, realistic apparatus arrangement, and a concrete graph plan typically loses marks heavily.

DefineindependentdependentMethodapparatusmeasurementsAnalysisderived valuesgraph planSafetyrisk + controlrealistic labMark-scoring planning responseWorkable setup + measurable variables + valid graph + justified precautions(not generic statements)

P5.1.2 Defining the Problem Correctly

Variable map before method writing

The first technical task is to map variables precisely. This should be done before listing apparatus, because instrument choice depends on what you are measuring and how accurately it must be measured.

High-scoring statement pattern

\"Vary wire length L from 0.20m to 1.00m in equal steps. For each L, measure V and I, then calculate R=V/I. Keep wire material, cross-sectional area and temperature constant.\"

Common weak wording

\"Change the variable and take readings\" is too vague. Q1 expects explicit quantity names, ranges, and control method.

Independentset and varysystematicallyDependentmeasure responsefor each settingControlshold constantfor fair testPrecisionfit-for-purposeinstrument choiceThe \"variable map\" is the core of a high-scoring planning answer

Variable checklist for Q1

  • Define the independent variable and how it is set.
  • Define the dependent variable and the instrument used.
  • List control variables and write how each is held constant.
  • State the number of readings and spacing strategy.
  • Include repeats if random uncertainty is expected to be significant.

P5.1.3 Methods of Data Collection (Workable Setup)

Apparatus + procedure must be executable

Cambridge mark schemes reward methods that can be performed without hidden assumptions. Your diagram must match your written sequence and your instrument choices must be fit for the required precision.

Instrument fit-for-purpose examples

  • Measure L with a metre rule to the nearest 1 mm.
  • Measure current with ammeter range that avoids clipping/overload.
  • Use data logger/light gate where timing precision is critical.
R=VI

Even in a planning response, include intended derived equations clearly when they are part of data acquisition and processing.

Example planning diagram: wire resistance vs lengthd.c. supplyAammetertest wire (length L)VvoltmeterMeasure V and I, then calculate R = V/I for each LPlot R against L, gradient = ρ/A

What examiners look for

  • Clear sequence: set value, then measure, record, and repeat.
  • Realistic range and increment size.
  • How controls are physically enforced.
  • How many readings and why.

Frequent planning losses

  • No diagram or unlabeled diagram.
  • No statement of control variables.
  • Instrument named but no measurable quantity linked.
  • Method too brief to generate a full table for graphing.

P5.1.4 Method of Analysis in Planning Answers

Write the graph plan before collecting data

Q1 frequently rewards candidates who pre-plan linearisation. You should specify the graph, state the expected straight-line form, and explain how gradient/intercept yields the target constant.

Standard linearisation forms:

y=axn⇒lg⁡y=nlg⁡x+lg⁡a
y=aekx⇒ln⁡y=kx+ln⁡a
y=mx+c

Example planning line

\"Calculate T2 from measured T values and plot T2 against L. The gradient equals 4π2/g, so calculate g from g=4π2/gradient.\"

Method of analysis: choose graph before collecting dataGiven modelT = 2π√(L/g)LineariseT² = (4π²/g)LPlotT² against LLT²best-fitworst acceptable

Analysis checklist for Question 1

  • State which quantities are measured directly.
  • State which quantities are calculated before plotting.
  • State graph axes clearly with transformed quantities where needed.
  • State exactly what constant comes from gradient/intercept.
  • State expected trend (e.g., straight line through origin if model predicts this).

P5.1.5 Additional Detail and Safety Considerations

Safety marks are specific, not generic

A valid Q1 response identifies concrete hazards in the proposed setup, then states realistic controls. High-scoring answers also improve reliability through calibration, alignment checks, and repeated readings.

High-value additions

  • Initial trial run to confirm range and avoid saturation/overflow.
  • Calibration/zero checks before recording final data.
  • Repeat each reading and average where scatter is significant.
  • Name one dominant uncertainty source and how to reduce it.

Syllabus practical-tool references you can mention when relevant:

oscilloscope for voltage/current/time/frequency; light gates with data logger for time, velocity, acceleration; motion sensors for automated displacement-time data.

Risk-control mapping expected in Q1hot apparatusheatproof mat + allow cooling + handle with tongswire snappingwear eye protection + limit load + secure clampselectrical shortcheck insulation + switch off before rewiring + low voltageGeneric statements score poorly: tie each precaution to a named risk in your setup.

Do include

  • Named hazard + named precaution pairings.
  • How variables are actually kept constant.
  • Specific arrangement details in the diagram labels.

Avoid

  • \"Take care\" without saying what risk is controlled.
  • Method that cannot produce enough points for a graph.
  • Apparatus list with no linked measurement procedure.

Numericals — Structured Q1 Planning Drills

These are Paper 5 planning-style structured tasks. Treat each one like a mark-scheme response: exact variables, measurable procedure, graph plan, and safety.

1. Pendulum planning with linearisation [8 marks]

Design an experiment to determine g using a simple pendulum and stopwatch.

(a) State independent, dependent, and two control variables. [2]

(b) Describe how readings are taken to reduce timing uncertainty. [2]

(c) State graph to plot and how g is obtained. [3]

(d) Give one safety/quality-control detail. [1]

Solution:

(a) Independent: pendulum length L. Dependent: period T. Controls: small angle, same bob mass/string type.

(b) For each L, time 10 oscillations and divide by 10 for T. Repeat and average to reduce random reaction-time error.

(c) Use T=2πL/g, so T2=(4π2/g)L. Plot T2 against L. If gradient is m, then g=4π2/m.

(d) Keep swing angle small (typically below 10∘) so SHM approximation remains valid and systematic error is reduced.

2. Wire resistance planning and constant extraction [9 marks]

Plan an experiment to test R=ρL/A for a wire and determine resistivity ρ.

(a) State IV, DV, and three controls. [3]

(b) Explain measurements and derived calculations. [2]

(c) State graph and how to obtain ρ. [3]

(d) If gradient of R vs L graph is 5.6Ωm−1 and A=2.8×10−7m2, calculate ρ. [1]

Solution:

(a) IV: L. DV: R. Controls: wire material, cross-sectional area A, wire temperature.

(b) Measure V and I for each L, then calculate R=V/I. Use at least 6 lengths over a suitable range.

(c) Plot R against L. Gradient m=ρ/A, so ρ=mA.

(d) ρ=mA=(5.6)(2.8×10−7)=1.57×10−6Ωm.

3. Oscilloscope planning for frequency [7 marks]

A student must determine the frequency response of a component using an oscilloscope.

(a) State one independent and one dependent variable. [1]

(b) Write a workable data-collection sequence using oscilloscope readings. [3]

(c) Give one suitable graph for analysis and one safety/procedure detail. [3]

Solution:

(a) IV: driving frequency f. DV: output amplitude (or phase shift) from oscilloscope trace.

(b) Set function generator to a chosen f, allow stable waveform, read amplitude using calibrated vertical scale; repeat for increasing f values with equal spacing near expected resonance region.

(c) Plot amplitude against frequency to identify peak response (or plot phase vs frequency). Keep input amplitude constant and verify oscilloscope time-base calibration before readings.

4. Light-gate planning with uncertainty focus [8 marks]

Plan an experiment using two light gates and a data logger to determine acceleration of a trolley on an incline.

(a) State variables and one control strategy. [2]

(b) Explain how velocities and acceleration are obtained from gate data. [3]

(c) State one graph option and how gradient/intercept is interpreted. [2]

(d) Give one major uncertainty source and one improvement. [1]

Solution:

(a) IV: trolley release position (or incline angle). DV: acceleration a. Control: keep trolley mass and track condition constant.

(b) Use interrupt card length ℓ with gate times t1,t2 to obtain v1=ℓ/t1 and v2=ℓ/t2; then a=(v2−v1)/Δt where Δt is logger-recorded interval between gates.

(c) Plot v2 against v1 for systematic runs is less direct; better plot v against t for multiple gates so gradient gives a.

(d) Major uncertainty: friction variation along track. Improvement: clean track/wheels and run multiple repeats for each setting to average random scatter.