IGCSE Physics Paper 6: the Alternative to Practical
Paper 6 is a written exam about practical work. You do not do an experiment, but you are asked to read instruments, record data, draw graphs, plan investigations and suggest improvements. It is worth 20% of your Cambridge IGCSE Physics grade, and it rewards technique more than memory.
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The format
- Cambridge IGCSE Physics (0625) Paper 6: 1 hour, 40 marks, all questions compulsory.
- It is worth 20% of the qualification, the same as Paper 5, the lab-based practical test. Your school enters you for one or the other.
- It tests assessment objective 3, experimental skills and investigations, and you do not do any experiments in the exam.
The experiments it draws on
The syllabus lists the experimental contexts you should be familiar with, including:
- measuring lengths, volumes, forces, small distances and short time intervals;
- finding derived quantities, such as the extension per unit load of a spring, a resistance or an acceleration;
- testing the relationship between two variables, for example potential difference against the length of a wire;
- heating and cooling, with temperature measurements;
- springs and balances, and timing motion or oscillations such as a pendulum;
- electric circuits, measuring current and potential difference;
- optics with pins, mirrors, prisms, lenses and glass or Perspex blocks;
- simple procedures in unfamiliar situations.
The skills that earn marks
- Reading instruments to the right precision, including to the nearest half division, and correcting zero errors.
- Recording data in a table with a column heading, unit and consistent number of decimal places.
- Drawing graphs: labelled axes with units, sensible scales that use most of the grid, neatly plotted points and a best-fit line.
- Processing data: calculating gradients from a large triangle, and averages from repeats.
- Planning: identifying independent, dependent and control variables, the range and number of readings, and safety.
- Evaluating: spotting anomalous results, sources of inaccuracy and realistic improvements.
Reading and recording
A student measures the length of a spring with a ruler marked in millimetres. The reading is between 4.3 cm and 4.4 cm, closer to 4.35 cm. How should it be recorded?
- Read to the nearest half division: 1 mm divisions allow 0.5 mm, so record 4.35 cm (or 43.5 mm).
- In the table, the heading should be “length / cm”, and every value should have the same number of decimal places.
Processing a graph
A graph of extension (y-axis, in cm) against load (x-axis, in N) is a straight line through the origin passing through (6.0 N, 4.8 cm). Find the gradient and say what it means.
- Gradient = 4.8 / 6.0 = 0.80 cm/N, using a triangle that covers most of the line.
- It is the extension per unit load, so the spring stretches 0.80 cm for every newton. The spring constant is the reciprocal: 1.25 N/cm.
Timing an oscillation
A student times 10 swings of a pendulum as 15.6 s. Why time 10 swings, and what is the period?
- Timing many swings reduces the effect of reaction time on the result.
- Period = 15.6 / 10 = 1.56 s.
How to prepare
- Do as many real experiments as you can in class: Paper 6 is easier if you have handled the apparatus.
- Practise past Paper 6 questions with the mark scheme beside you, and copy the exact wording that earns marks.
- Keep a checklist for tables and graphs and use it every time.
- Learn standard improvements, such as repeating readings, using a larger range, using a fiducial marker for timing, or viewing a scale at eye level to avoid parallax.
A model planning answer
Planning questions often carry several marks. Here is the shape of a full answer to “Plan an experiment to find how the length of a wire affects its resistance.”
- Apparatus: a power supply, an ammeter in series, a voltmeter across the wire, a metre rule and crocodile clips.
- Variables: change the length (independent); measure resistance from V and I (dependent); keep the wire material, thickness and temperature the same (controlled).
- Range and number: at least five lengths, such as 20 cm to 100 cm in 20 cm steps, with repeats.
- Method: record V and I for each length, calculate R = V / I, and keep the current low and switch off between readings so the wire does not heat up.
- Table and graph: columns for length / cm, V / V, I / A and R / Ω, then a graph of R against length.
- Conclusion: a straight line through the origin shows resistance is directly proportional to length.
More questions
Do Core and Extended candidates sit the same Paper 6?
Yes. All candidates take one practical paper, Paper 5 or Paper 6, whatever their route.
Common mistakes
- Missing units in table headings or graph axes.
- Choosing a graph scale that uses less than half the grid.
- Calculating a gradient from a tiny triangle or from two data points instead of the line.
- Writing vague improvements such as “be more careful”.
- Giving readings to inconsistent numbers of decimal places.
Practice questions
Try each one before opening the answer.
Q1. A thermometer reads 21.5 °C before heating and 46.0 °C after. What is the temperature rise?
Show answer
Q2. Name one way to make the timing of a falling object more accurate.
Show answer
Q3. What is the independent variable when investigating how the length of a wire affects its resistance?
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Frequently asked questions
Is Paper 6 easier than Paper 5?
They test the same skills and are worth the same 20%. Paper 6 is written, so it suits students who have practised the question styles.
Do I need to learn every experiment?
You need to know the listed contexts and the general skills, because Paper 6 can also describe an unfamiliar procedure.
How long is Paper 6?
1 hour, for 40 marks.
Key takeaways
- Paper 6: 1 hour, 40 marks, 20% of IGCSE Physics.
- No experiments, but questions are all about practical work.
- Tables, graphs, gradients, variables and improvements earn the marks.
- Practise with past papers and mark schemes.
- Real lab experience makes it easier.