How do the angle of release at (15.0° , 30.0°, 45.0°,60.0° and 75.0°)± 0.5° of a simple pendulum of length (50.00± 0.05) cm and mass (50.00± 0.01) g undergoing 10 oscillations affect its frequencyHL
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6
Official IB Result
18/24
Criteria A: Research Design
4/6
0
3
6
Criteria StrandsPro
A.1Research question context
Excellent
A.2Methodological considerations for collecting data
Moderate
A.3Methodological considerations
Moderate
Criteria Feedback
- The student sets the investigation in a clear physics context and identifies the independent, dependent, and controlled variables.
- The student includes enough procedural detail, a materials list, and a diagram so the overall method is understandable.
- The student recognises the importance of repeated trials and timing multiple oscillations to improve reliability.
- There are internal inconsistencies in the investigation statement, especially around the number of oscillations timed and the stated string length.
- Some methodological choices are not fully justified, such as controlling gravity and not clearly explaining why each control matters.
- The procedure is not fully reproducible because the release-angle setup and timing protocol are not described with complete precision.
1.1·Strength
Page 1
The research question is framed in a specific physics context with a clear independent variable, dependent variable, and controlled quantities. This gives the investigation a focused direction and makes the aim of the experiment immediately understandable.
1.2·Suggestion
Page 2
The student has identified the key theoretical boundary, which is useful context. To strengthen this further, the student should briefly explain why the small-angle approximation breaks down and how that motivates testing 15° to 75° specifically.
1.3·Weakness
Page 3
This sentence contains a major internal inconsistency: it says the pendulum has a string diameter of 40 cm, then says the time is measured for 20 oscillations, which clashes with the earlier 10-oscillation framing. The student should make the investigation statement fully consistent so the reader can identify exactly what was measured and controlled.
1.4·Weakness
Page 4
The method for obtaining the period is not fully reproducible here because the procedure depends on timing exactly ten oscillations, while later sections switch to 20. The student should resolve this contradiction and state one unambiguous measurement protocol.
1.5·Question
Page 4
If the mass does not affect the period directly, why is it being controlled here beyond keeping the apparatus unchanged? This is a useful moment to distinguish variables that must be controlled because they could interfere with measurements from those that are theoretically irrelevant.
1.6·Suggestion
Page 6
The method would be clearer if the student stated exactly where the protractor is aligned relative to the vertical equilibrium position and how the release angle is read each time. That extra detail would remove ambiguity and make the procedure easier to reproduce.
1.7·Weakness
Page 6
This step is not methodologically sound as written because it cannot be followed literally: repeating step 2–7 would also repeat setup actions unnecessarily. The student should specify exactly which measurement step is repeated and how many total trials are taken at each angle.
Criteria B: Data Analysis
4/6
0
3
6
Criteria StrandsPro
B.1Communication of data recording and processing
Moderate
B.2Consideration of uncertainties
Moderate
B.3Data processing quality
Moderate
Criteria Feedback
- The student presents their data in an organised way, with raw and processed tables, sample calculations, and a graph that makes the main trend easy to see.
- The student uses repeated trials and attempts to include uncertainty and error bars, which is a good sign of thoughtful analysis.
- The student's processing shows the intended chain from time readings to period and frequency.
- The data handling is affected by important inconsistencies, especially the mismatch between 10 and 20 oscillations and conflicting uncertainty values.
- Some uncertainty treatment is not applied correctly, and the explanation of how uncertainty affects frequency is not always mathematically sound.
- The analysis relies too heavily on a linear fit and does not fully account for the fact that the theoretical relationship is not simply linear at larger amplitudes.
2.1·Weakness
Page 7
This caption is inaccurate and undermines clarity: the investigation is about release angle, not string length, and the text says ten oscillations while the table heading says 20. The student should correct both the variable named in the caption and the oscillation count.
2.2·Weakness
Page 7
This sentence states the opposite of what the table shows: frequency decreases as release angle and period increase. The student should correct this wording because precision in trend description is essential for accurate scientific communication.
2.3·Weakness
Page 7
The raw-data heading conflicts with the method and later processing, which use 10 oscillations. This makes it difficult to know what the measured quantity actually was, so the student needs to make the unit of analysis consistent throughout the report.
2.4·Strength
Page 7
The processed table is well structured and lets the reader follow the chain from raw time readings to mean time, period, frequency, and uncertainty. This is effective communication because each transformed quantity is labelled and connected to the research question.
2.5·Strength
Page 8
The student makes a sensible link between the measured spread and a plausible source of random error. That kind of cause-and-effect explanation is valuable because it shows the data are being interpreted rather than merely tabulated.
2.6·Suggestion
Page 8
The student is doing the right kind of processing by using repeated trials. To make the work stronger, it would help to show the full standard-deviation working once and then briefly state that the same method was applied to the other angles.
2.7·Weakness
Page 8
The claim that the standard deviations are all close to zero is too general to be precise. The student should report the spread relative to the mean or uncertainty of the mean, because the raw standard deviation values are not enough on their own to justify the level of precision stated here.
2.8·Question
Page 9
What does a straight-line fit actually imply about the pendulum relationship at these angles, and is a linear model the most suitable one for finite-amplitude pendulum motion? Reflecting on that choice would strengthen the analysis beyond just reporting .
2.9·Weakness
Page 9
This interpretation is not precise: the uncertainty is being used to justify a relationship that is stated incorrectly as angle being inversely proportional to angle. The student should link the uncertainty to the frequency values themselves, not to a mathematically impossible proportionality claim.
2.10·Suggestion
Page 9
The value is useful, but the student should also comment on whether the linear model is theoretically appropriate. A high alone does not prove the model matches the physics of the pendulum at larger amplitudes.
2.11·Weakness
Page 9
The uncertainty method is not clearly justified here. The student should show how the timing uncertainty propagates into frequency and make clear whether the value is absolute or relative before using it in later interpretation.
Criteria C: Conclusion
4/6
0
3
6
Criteria StrandsPro
C.1Conclusion relevance and support
Moderate
C.2Scientific context comparison
Moderate
Criteria Feedback
- The student's conclusion is directly tied to the observed trend in the processed data and clearly states what happens to period and frequency as the release angle increases.
- The student makes a relevant comparison with scientific context by referring to the small-angle approximation and finite-amplitude behaviour.
- The student begins to interpret the low-angle data and discusses how the results change at larger angles.
- The conclusion sometimes overstates the evidence by describing the relationship as inverse proportionality when the data only show a negative trend.
- The comparison with theory is limited because it relies too much on a single point rather than comparing the broader pattern.
- The conclusion does not fully resolve the mismatch between the experimental results and the theoretical expectation, especially at larger angles.
3.1·Weakness
Page 10
This is too strong a claim for the evidence provided. The data show a negative trend, but that is not the same as proving inverse proportionality, especially with only five angles and a linear fit that is not theoretically ideal.
3.2·Question
Page 10
If the small-angle model predicts an approximately constant frequency, how should the student interpret the small differences between 15° and 30°? Thinking about that would help distinguish experimental scatter from a true amplitude effect.
3.3·Suggestion
Page 10
This is a promising statistical observation. To strengthen the conclusion, the student should briefly explain what overlapping error bars can and cannot prove, so the claim does not overstate the evidence.
3.4·Strength
Page 10
The conclusion is anchored in the processed graph and directly addresses the direction of the relationship. This is good practice because the student is not making a claim in isolation; the statement is tied to the displayed trend.
3.5·Weakness
Page 10
The comparison with theory is useful, but it is based on only one data point, so it cannot justify the overall conclusion for all angles. The student should compare multiple angles or explain why 15° is representative of the wider pattern.
3.6·Weakness
Page 11
The conclusion leans too heavily on the linear fit without addressing whether the model is physically appropriate. The student should state that the graph shows a negative trend, but avoid presenting linearity and inverse proportionality as established facts.
3.7·Suggestion
Page 11
The practical significance is a good addition. The student could strengthen the conclusion by linking this statement more explicitly back to the experimental pattern at the larger angles, especially 60° and 75°.
Criteria D: Evaluation
6/6
0
3
6
Criteria StrandsPro
D.1Methodological weaknesses
Good
D.2Suggested improvements
Moderate
Criteria Feedback
- The student identifies several specific limitations, including reaction time, release inconsistency, angle alignment, oscillation counting, friction, and possible string deformation.
- The student distinguishes between different sources of error rather than giving only generic comments.
- The student suggests practical improvements such as video analysis, a fixed release mechanism, and better angle measurement.
- The evaluation does not clearly rank the limitations by importance or explain which ones had the greatest effect on the results.
- Some limitations are identified well but not fully connected to the size or direction of their impact on the data.
- Several improvements are sensible but would be stronger if the student explained more explicitly how they would reduce uncertainty or improve validity.
4.1·Weakness
Page 12
The weakness is identified, but the student does not explain how large its effect was relative to the other limitations. The evaluation should rank the main sources of error by impact, using evidence from the spread in the data or the size of the uncertainties.
4.2·Strength
Page 12
This is a specific and credible limitation, and the student correctly links it to the timing data. Identifying a concrete source of random error shows stronger evaluation than listing generic weaknesses.
4.3·Weakness
Page 13
This is a strong limitation to identify, but the student does not fully connect it to the experiment’s outcomes. The response should explain that pivot friction would systematically increase the measured period, which would in turn lower the calculated frequency across all angles.
4.4·Weakness
Page 13
This is a valid limitation, but it is still presented in a general way. The student should explain whether the angle uncertainty is likely to create a random spread, a systematic offset, or both, and how that would affect the final frequency trend.
4.5·Suggestion
Page 13
The improvement is relevant, but the student should justify why this particular fix is better than simply changing the pivot design. A brief explanation of how it would preserve a consistent effective length would make the recommendation more convincing.
4.6·Weakness
Page 13
The extension is relevant, but it stays broad and descriptive rather than evaluating the limits of the method used here. The student should connect the proposed follow-up more clearly to the observed discrepancy at larger angles and explain what new data would be needed to test the approximation properly.
4.7·Suggestion
Page 13
This is a realistic improvement, but it would be stronger if the student stated how it would improve validity or reduce uncertainty. For example, the student could explain that a digital protractor reduces parallax and gives a more repeatable release angle.