GCSE Physics resources
AQA GCSE Forces
Add loads to a spring or wire, measure extension from the unloaded length and plot force against extension. Increase the load carefully, remove loads for repeats where appropriate and identify the straight-line region.
Start here
Add loads to a spring or wire, measure extension from the unloaded length and plot force against extension. Increase the load carefully, remove loads for repeats where appropriate and identify the straight-line region.
Core learning content
Start with this short teaching sequence for Force and Extension Required Practical. Read the model, use the visual, then test your recall before moving into examples and exam practice.
Add loads to a spring or wire, measure extension from the unloaded length and plot force against extension. Increase the load carefully, remove loads for repeats where appropriate and identify the straight-line region.
Measure the unloaded length first, then subtract it from every loaded length to find extension. Add masses carefully and wait for oscillations to stop. A force-extension graph shows the proportional region; the first clear departure from a straight line is the limit of proportionality.
Choose a relationship because of the physical change in the question, not because it is familiar. Weight: W = mg (N, kg, N/kg). Newton’s second law: F = ma (N, kg, m/s²). Momentum: p = mv (kg m/s). Keep the unit next to each value while you substitute.
Explain zero reading, eye-level measurement, control of the apparatus and how the graph identifies the limit of proportionality. Before writing, underline the command word and identify the information that matters. Keep a calculation as equation, substitution and answer with unit; keep an explanation as a linked chain using because, so or therefore. Finish by checking that the final sentence answers the exact context in the question and that the number, direction or conclusion agrees with the evidence given.
Retrieval practice
Answer without looking back first. The feedback explains the model, so a wrong answer still helps you learn.
Mini quiz 1
Mini quiz 2
Mini quiz 3
Try it
How can repeats and a graph reveal the limit of proportionality?
What to notice: the readout and written explanation remain available if you do not use the controls.
Worked examples
Cover the answer, attempt the method and then compare your physics language as well as the number.
Extension = 48 mm.
Force = 2.94 N.
Extension is proportional to force up to about 4 N, the limit of proportionality.
Misconception clinic
Each of these is tempting because it sounds almost right. Replace it with the precise physics before you meet it in a question.
Independent practice
Use the working space first. Reveal the guidance only after you have committed to an answer, then improve the exact part that would gain the next mark.
Force/load applied.
Extension of the spring/wire.
Extension is the change from original length, not total loaded length.
Keep the same spring, wait for oscillations to stop and read scale at eye level.
To avoid damaging the spring and to obtain stable readings.
Use a pointer/set square or a scale with finer divisions and repeat readings.
Questions pupils ask
Forces questions often hide a simple model inside a diagram. Draw the forces, find the resultant, then connect the resultant to the motion or deformation.
Read the snapshot, attempt the worked examples without looking, complete the mini quizzes and then use the practice questions to check your wording and method.
Next step
Physics sticks when you move between explanation, retrieval and application.