The pendulum is one of the most common 0625 Paper 5 experiments. Set each length using the magnified rule, release the bob and time 10 oscillations yourself with the stopwatch. Complete the table, plot your own graph of T² against l and use its gradient to find the acceleration of free fall. The timing is real, so allow about 20 minutes.
Past-paper referenceOriginal experiment, wording and numbers, written in the style of Cambridge IGCSE Physics 0625 Paper 5 (Practical Test), Question 1. It is not copied from a past paper.
Practise next: 0625/51 October/November 2022, Question 1 (timing a pendulum at five lengths, graph of T squared against l) · official past papers
Practise next: 0625/51 October/November 2024, Question 1 (the period of a pendulum, then planning a graph of T squared against d) · official past papers
This type of experiment has come up 23 times (11 in Paper 5, the Practical Test, and 12 in Paper 6, the Alternative to Practical) in the past papers we checked. Show the list
Checked: Cambridge IGCSE Physics 0625 Papers 5 and 6, 2014 to 2025. Only the papers in our collection are listed, so the real number may be higher. Question papers are available from Cambridge.
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How this question is marked
Method (a)
A technique that really finds the centre of the bob: line it up with the scale using a set square, at eye level.
Table (b)
Headings with quantity and unit, every time taken from the stopwatch with the pendulum swinging at that length, T = t / 10, and T² to 2 or 3 significant figures.
Graph (c)
Axes labelled, sensible scales (a false origin on the T² axis is fine), accurate plotting and a well-judged best-fit line.
Analysis and evaluation (d) to (g)
A large gradient triangle, g calculated from your own gradient with the unit m/s², why timing many oscillations helps, and a precaution that really improves the timing.
Habits that save marks
Count from zero. Start the stopwatch as the bob passes the marker and say “zero”, then stop on “ten”.
Time from the centre of the swing, where the bob moves fastest, not from the ends where it pauses.
Small swings only. The bench releases the bob through a small angle, as you should in the lab.
l is to the centre of the bob, not to its bottom and not just the string.
The marking follows the conventions in published Cambridge mark schemes. The experiments, readings and wording on this page are our own.