The planning question is the one part of the Physics practical paper you can prepare for completely at home, with a pen and paper, no lab needed. It appears as the final question of Paper 4 in Combined Science (Physics) and as the final question of Paper 3 in Pure Physics, and it is usually worth around a fifth of the whole practical paper. That is a big chunk of marks sitting in a question that most students rush in the last ten minutes.
Here is how we teach it at Dojo, based on the mark schemes we worked through when we sat these papers ourselves.
Why students lose marks here
Most candidates know the physics. What they lose marks on is structure. The examiner is ticking off a checklist, and if an item is missing from your answer, the mark is gone even if the idea was "obvious".
Common reasons for lost marks:
- Writing a paragraph story instead of a labelled, ordered plan.
- Naming apparatus vaguely ("a ruler") instead of specifically ("a metre rule reading to 0.1 cm").
- Never stating what you will keep constant.
- Forgetting to say how the results will be processed into a conclusion.
- Writing a generic safety line such as "be careful" that earns nothing.
The seven-part skeleton
Use the same seven headings every single time. Write them down before you write any content, then fill them in. This alone usually adds several marks.
- Aim and variables. State the independent variable you will change, the dependent variable you will measure, and at least two variables you will keep constant.
- Labelled diagram. Draw it. A clear circuit diagram or side-view sketch of the setup, labelled, is often worth a mark on its own and saves you writing.
- Apparatus list with precision. Name the measuring instrument and its scale: micrometer screw gauge (0.01 mm), digital stopwatch (0.01 s), ammeter (0 to 1 A), balance (0.1 g).
- Procedure, numbered. Short steps in order. Include the range and number of readings: "Repeat for six different lengths from 20.0 cm to 100.0 cm in 20.0 cm steps."
- Table of results. Draw an empty table with column headings and units, including any derived column you need.
- How you reach the conclusion. Say which graph you will plot, what shape you expect, and what the gradient or intercept tells you.
- Precautions. Two or three that are specific to this experiment, plus one genuine safety point if there is a real hazard.
Mark-scheme phrasing worth memorising
Examiners reward precise language. Bank these lines:
- "Repeat each reading twice and take the average to reduce the effect of random error."
- "Time 20 oscillations and divide by 20 to reduce the percentage uncertainty in the period."
- "View the scale perpendicular to the rule to avoid parallax error."
- "Switch off the circuit between readings so the wire does not heat up and change its resistance."
- "A straight line through the origin would show that y is directly proportional to x."
Worked example
Question: Plan an experiment to investigate how the resistance of a nichrome wire depends on its length.
Variables. Independent: length L of wire. Dependent: resistance R. Constant: diameter of the wire, the material (same reel of nichrome), and the temperature of the wire.
Apparatus. Nichrome wire about 1.2 m long, metre rule (0.1 cm), micrometer screw gauge (0.01 mm), ammeter (0 to 1 A), voltmeter (0 to 5 V), battery, switch, two crocodile clips, rheostat.
Diagram. Series circuit of battery, switch, rheostat, ammeter and the test length of wire, with the voltmeter connected in parallel across the test length.
Procedure.
- Measure the diameter of the wire at three different points with the micrometer and take the average.
- Tape the wire straight alongside the metre rule and connect crocodile clips at 0.0 cm and 20.0 cm.
- Close the switch, adjust the rheostat, and record the voltmeter reading V and ammeter reading I.
- Open the switch immediately after taking the readings.
- Calculate resistance using R = V / I.
- Repeat for L = 40.0, 60.0, 80.0 and 100.0 cm, taking two sets of readings at each length and averaging.
Table. Columns for L / cm, V / V, I / A and R / Ω.
Conclusion. Plot R / Ω on the vertical axis against L / cm on the horizontal axis. A straight line passing through the origin shows that resistance is directly proportional to length.
Precautions. Keep the current small and switch off between readings so the temperature of the wire stays constant. Ensure the wire is pulled taut and straight before measuring its length. Do not touch the wire while current flows in case it becomes hot.
How to practise this week
Take five past-paper planning questions and write only the seven headings and a bare-bones answer for each, ten minutes per question. You are training the structure, not the handwriting. Then compare against the mark scheme and highlight every phrase you missed.
If you want feedback on your own plans line by line, come and try a lesson with us. Message us on WhatsApp to book a free trial class, no obligation.