AQA GCSE Physics required practicals
Required practicals are examined in your written GCSE Physics papers. Here is the AQA list and how to revise each one.
On this page
The required practicals
- Specific heat capacity: heating a block and measuring the temperature rise.
- Thermal insulation (separate Physics): comparing how well materials reduce heat loss.
- Resistance: how the length of a wire and combinations of resistors affect resistance.
- I-V characteristics: current and potential difference for a resistor, a filament lamp and a diode.
- Density: measuring the density of regular and irregular objects and liquids.
- Force and extension: stretching a spring and finding the spring constant.
- Acceleration: how force and mass affect acceleration.
- Waves: measuring the speed of water waves and waves on a string.
- Light (separate Physics): reflection and refraction.
- Infrared radiation: how the surface of an object affects the radiation it emits and absorbs.
Combined Science students do most but not all of these. Check the current AQA specification for your course.
What exam questions ask
- Describe the method in clear steps.
- Identify the independent, dependent and control variables.
- Explain how to make the results accurate and safe.
- Analyse results from a table or graph.
How to revise them
- For each practical, learn the aim, equipment, method, variables and the graph you would draw.
- Learn one improvement for each, such as repeating readings or using a more precise instrument.
- Practise six-mark method questions from past papers.
Other boards, such as Edexcel, have their own core practicals; check your specification.
Key practical skills
Every required practical tests the same skills. You need to know the independent variable (what you change), the dependent variable (what you measure) and the control variables (what you keep the same). You should be able to describe how to take accurate measurements, why repeating readings and calculating a mean helps, how to spot anomalous results, and how to draw a line of best fit. These ideas apply to any experiment, even one you have not done.
Worked examples
Example 1: specific heat capacity
A 1 kg aluminium block is heated by a 50 W heater for 300 s. Its temperature rises by 16 °C. Find its specific heat capacity.
- Energy supplied = Pt = 50 × 300 = 15 000 J.
- c = E/(mΔθ) = 15 000/(1 × 16) ≈ 940 J/kg °C.
- The accepted value is about 900 J/kg °C. The result is a bit high because some energy is lost to the surroundings; insulating the block reduces this.
Example 2: resistance of a wire
A wire has 3.0 V across it and 0.60 A through it. Find its resistance. How does the resistance depend on length?
- R = V/I = 5.0 Ω.
- Resistance is directly proportional to length: doubling the length doubles the resistance.
Example 3: density of an irregular object
A stone has mass 120 g. When lowered into a displacement can, it pushes out 48 cm³ of water. Find its density.
- ρ = m/V = 120/48 = 2.5 g/cm³.
Example 4: force and extension
A spring extends by 4 cm under a 2 N load and by 8 cm under 4 N. Find the spring constant.
- Extension is proportional to force. k = F/e = 2/0.04 = 50 N/m.
Example 5: waves in a ripple tank
In a ripple tank, 10 waves span 15 cm and 5 waves pass a point each second. Find the wave speed.
- λ = 15/10 = 1.5 cm = 0.015 m; f = 5 Hz.
- v = fλ = 0.075 m/s. Measuring across several waves reduces the uncertainty.
What each practical tests
- Specific heat capacity: energy, power and heat loss.
- Resistance and I-V characteristics: circuits, Ohm's law and how components behave.
- Density: measuring mass and volume, including displacement for irregular shapes.
- Force and extension: Hooke's law and the limit of proportionality.
- Acceleration: Newton's second law, using light gates or a timer.
- Waves: measuring frequency, wavelength and speed.
- Infrared radiation: how surface colour and texture affect emission and absorption.
Separate Physics students also do practicals on thermal insulation and on light, such as reflection and refraction. Check your board's list for the exact set.
Common mistakes
- Confusing repeatable (same person, same method) with reproducible (different person or method).
- Saying “to make it a fair test” without naming the control variable.
- Including anomalous results when calculating a mean.
- Joining points dot-to-dot instead of drawing a line of best fit.
Practice questions
Try each one before opening the answer.
Q1. In the acceleration practical, what is the independent variable when investigating force?
Show answer
Q2. Why does a matt black surface feel warmer in sunlight than a shiny white one?
Show answer
Q3. Why measure the length of several waves rather than one?
Show answer
Frequently asked questions
Can I be asked about a practical I have not done?
Yes. Questions can describe unfamiliar experiments and test the same skills, so focus on understanding the methods rather than memorising them.
How many marks are practicals worth?
On AQA, at least 15% of the marks in the exams test practical skills and knowledge. They are worth revising carefully.
Key takeaways
- Know the independent, dependent and control variables.
- Repeat readings and calculate a mean.
- Identify and ignore anomalies.
- Explain sources of error and how to reduce them.
- Expect questions on unfamiliar experiments using the same skills.
Where to go next
Revise the topics behind each practical.
Accuracy, precision and errors
These words have exact meanings in physics. A measurement is accurate if it is close to the true value. Measurements are precise if repeated readings are close to each other. A random error makes readings scatter around the true value; repeating and taking a mean reduces its effect. A systematic error shifts every reading by the same amount, for example a balance that is not zeroed; repeating does not help, but you can fix it by checking and correcting the equipment. A zero error is a kind of systematic error where an instrument does not read zero when it should.
How to describe a method
When a question asks you to describe a practical, write numbered steps in a logical order. Name the equipment, say what you measure and how, say what you keep the same, and explain how you would repeat readings and process the data, such as plotting a graph. Include one safety point if it is relevant. A clear method that someone else could follow earns full marks, even if it is not word for word what you did in class.
Practicals can feel like a separate topic, but they are really the physics you already know, seen through an experiment. Revise them alongside each topic, and they will reinforce each other.
Make one revision card per practical, with the aim, method, variables, results and sources of error, and test yourself on it regularly.
Before the exam, sketch the graph you would expect from each practical and say what its shape shows. This quick check covers a lot of likely questions.