Quick answer: Paper 6 is a 1-hour, 40-mark written paper about experiments you do not carry out in the exam. It tests the same experimental skills as Paper 5: variables, tables, graphs, conclusions and evaluation. Most marks are won with careful units, sensible precision, a well-drawn graph and specific, not vague, answers.
Who this is for: Cambridge IGCSE Physics students entered for Paper 6, and parents who want to know what it asks.
What is Paper 6, and how does it differ from Paper 5?
Every Cambridge IGCSE Physics (0625) student takes one practical paper from a choice of two. This is from the official syllabus for 2026, 2027 and 2028:
- Paper 5 (Practical Test): 1 hour 15 minutes, 40 marks. Students do experiments in a laboratory.
- Paper 6 (Alternative to Practical): 1 hour, 40 marks. No experiments. Students answer written questions about experiments.
Both are worth 20% of the qualification. Both test AO3 (experimental skills and investigations), the same skills and the same experimental contexts. All questions are compulsory. Core and Extended students both take one of these papers, so the questions are built to work across the full grade range.
The school decides which paper students are entered for, so ask your teacher. Students do the hands-on practicals in their school lab. See our Cambridge IGCSE Physics 0625 page for the whole course.
Which experiments can Paper 6 ask about?
Cambridge lists the experimental contexts. They include:
- measuring length, volume or force, and small distances or short times
- finding a derived quantity, such as spring extension per unit load, a known resistance or an acceleration
- testing the relationship between two variables, for example potential difference across a wire and its length
- comparing quantities, such as angles of reflection or densities
- cooling and heating, including temperature
- springs and balances, and timing motion or oscillations
- electric circuits with current and potential difference
- optics with mirrors, prisms, lenses and glass or Perspex blocks
- simple apparatus in unfamiliar situations
A question can describe an experiment you have never seen. Reason about it. Do not rely on memory.
Paper 6 question types
The syllabus lists what you may be asked to do. In practice, it falls into five groups.
1. Apparatus and readings. Identify apparatus from a diagram, complete or label a diagram, and read scales. That includes reading to the nearest half-scale division and allowing for zero error.
2. Planning and method. Name the independent variable (the one you change) and the dependent variable (the one you measure). Say which variables you would control, how many values you would take and over what range. Describe the steps. Safety questions ask for a hazard and a sensible precaution.
3. Tables. Complete or design a table. Give each column the quantity and the unit, such as length / cm or I / A.
4. Graphs. Plot points, draw a best-fit line and read values from it. You may need a gradient or an intercept. Extended students may also draw a tangent to a curve to find a gradient.
5. Conclusions and evaluation. Describe the trend, say whether results support a prediction, spot an anomalous result, and suggest causes of error and improvements. At this level, results can be treated as equal within experimental accuracy if they agree within ±10%.
Worked example: table, graph and conclusion
Imagine a spring with a 10.0 cm natural length. A student adds loads and measures the length with a ruler marked in millimetres. The numbers are made up for practice.
| load / N | length / cm | extension / cm |
|---|---|---|
| 0.0 | 10.0 | 0.0 |
| 2.0 | 14.0 | 4.0 |
| 4.0 | 18.0 | 8.0 |
| 6.0 | 22.0 | 12.0 |
Check what the syllabus asks for:
- Headings carry the unit. Units go in the heading, not beside each number in the table.
- Precision matches the ruler. A millimetre ruler gives lengths like 14.0 cm, not “14”.
- Plot extension / cm (y) against load / N (x). Use scales that fill more than half the grid, such as 2 cm on the grid for 1, 2 or 5 units. Mark points with + or ×, and draw one thin, smooth best-fit line.
- Gradient. Draw a triangle whose hypotenuse covers at least half the line, and mark it on the graph. Using (0, 0) and (6.0, 12.0): gradient = 12.0 ÷ 6.0 = 2.0 cm/N. Give it to 2 or 3 significant figures. The gradient’s unit follows the axes.
- Conclusion. Extension is directly proportional to load, because the best-fit line is straight and passes through the origin.
A ±10% check. Suppose someone predicts 2.0 cm/N and the graph gives 2.1 cm/N. The difference is 0.1 ÷ 2.0 = 5%, so within ±10% and “equal within experimental accuracy”. A graph value of 2.5 cm/N differs by 25%, so it does not.
Mistakes that often cost marks
These come from what the syllabus expects, plus general exam technique.
- Leaving out units, or writing them next to each number in the table body. Put them in the heading.
- Inconsistent precision. If one length is 12.5 cm, the others should be to the same precision.
- Too many significant figures. A calculated answer should have the same number of significant figures as the least precise raw data used. If a load is 2.0 N, do not give 2.0000.
- Naming a variable but not how to control it. “Keep it the same” is weak. Say how, and why.
- Vague improvements. “Be more careful” earns nothing. “Repeat the timing and take an average” or “use a longer ruler to reduce the percentage error” is specific.
- Ignoring anomalies. If a point is clearly off the pattern, say so. Leave it out of the best-fit line, and say why.
- Overstating the conclusion. Stay within what the data show.
- Awkward graph scales. Stick to 1, 2 or 5 units per 2 cm.
Command words to watch (from the Cambridge syllabus)
| Command word | What it means | What to write |
|---|---|---|
| Describe | state the points of a topic / give characteristics and main features | Steps or features, in order |
| Explain | set out purposes or reasons / say why and/or how | A reason, not just a statement |
| Suggest | apply knowledge to situations where there are a range of valid responses | A sensible idea linked to this experiment |
| Calculate | work out from given facts, figures or information | Show the working, then the answer with a unit |
How to practise Paper 6 without a lab
Try this once or twice a week:
- Take one past practical question and cover the answers.
- Underline the command words and the variables.
- Write the method as numbered steps with a labelled diagram.
- Complete the table and graph, with units.
- Mark your own work with the mark scheme. Note exactly where marks were lost.
At TutorDock we teach online and do not run lab practicals. Students do those in their school lab. What we do is help with methods, results, graphs and evaluation, so students can answer the written questions. For help across the subject, see our IGCSE Physics tutoring in Saudi Arabia page or the IGCSE science hub.
FAQ: IGCSE Physics Paper 6
How long is Paper 6 and how many marks is it?
One hour and 40 marks. It is 20% of the Cambridge IGCSE Physics qualification.
Is Paper 6 easier than Paper 5?
Cambridge says both test the same experimental skills and contexts. They are two ways of showing the same skills, so neither is officially easier.
Do I need to memorise a list of experiments?
No. Cambridge lists the contexts you should know, but questions may use apparatus or methods that are new to you. Understanding the reasoning matters more.
Can I use a calculator in Paper 6?
The syllabus says calculators may be used in all parts of the examination.
Can TutorDock help with Paper 6?
Yes. We work through past practical questions with your child online, focusing on variables, tables, graphs and evaluation.
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Want help with Paper 6? Try a free class
If Paper 6 questions feel confusing, you can book a free trial class with TutorDock. Bring one practical question you found hard, and we will work through it together online. No obligation.
