Physics Experiment Execution and Analysis

Proof required

Submit your experimental design document: the physical quantity being measured, the theoretical relationship being tested, the equipment or simulation tool being used, the measurement protocol (what you will vary, what you will keep constant, how many measurements at each condition), and your uncertainty budget identifying the main sources of measurement error.

What gets checked

• Physical quantity is specific and measurable — not 'investigate how pendulums work' but 'measure the dependence of pendulum period on length and determine g with uncertainty'
• Theoretical relationship is stated before the experiment — the expected mathematical relationship between the variables must be stated in advance so that the data can test it rather than fit it
• Uncertainty budget identifies at least three distinct sources of measurement error — random measurement uncertainty, systematic instrument uncertainty, and at least one physical source (e.g., air resistance in a pendulum, fringe detection in optics)

Common mistakes

• Not stating the theoretical prediction before data collection — a physics experiment is designed to test a prediction, not to describe whatever data emerges; the prediction must come first
• Not considering the range over which the theoretical relationship holds — simple relationships often hold only within a limited range; the experimental design must consider where the approximation used in the theory breaks down

Resources

What a verifier looks for

• Ask the submitter to state the theoretical prediction they are testing — confirms they have framed the experiment as a test, not a description.
• Ask what the main systematic error is and how they will estimate it — distinguishing random from systematic errors is fundamental experimental physics.
• Ask what the expected result is and what would count as agreement with theory — a quantitative comparison criterion must be defined before data collection.

Proof required

Submit your raw data table (all measurements with individual uncertainty estimates), your error propagation calculation showing how the uncertainty on each measurement propagates to the uncertainty on the final derived quantity, and your comparison of the experimental result (with uncertainty) against the theoretical prediction — stating whether the result is consistent with theory within the quoted uncertainty.

What gets checked

• Raw data is submitted (not only the derived result) — all individual measurements with their assigned individual uncertainties
• Error propagation is shown explicitly — not 'the uncertainty is ±X' but the calculation showing how each measurement's uncertainty contributes to the final derived uncertainty
• Result is compared against theory with a quantitative consistency statement — 'the measured value of g = 9.6 ± 0.3 m/s² is consistent with the accepted value of 9.81 m/s² at the 1σ level' rather than 'close to the accepted value'

Common mistakes

• Reporting only the final derived quantity without the error propagation — a result without uncertainty is not a scientific measurement
• Performing too few measurements to detect systematic effects — a single series of measurements cannot distinguish random from systematic errors; at minimum two independent measurement sets should be compared

Resources

What a verifier looks for

• Ask the submitter to walk through the error propagation for the main measured quantity step by step — confirms they computed it rather than estimated it.
• Ask whether the result is consistent with the theoretical prediction at a specific confidence level — tests whether they understand what 'consistent within uncertainty' means quantitatively.
• Ask whether there is evidence of a systematic error in the data — for example, whether repeated measurements drift in one direction, suggesting a time-dependent systematic effect.

Proof required

Submit your complete lab report (2000–3500 words in standard format: abstract, introduction with theoretical context, experimental methods with full equipment/simulation specification, results with tables and figures, error analysis, and discussion with comparison to theory and sources of systematic error) plus a Q&A record showing specific challenges to the experimental approach or data interpretation and your responses. The reviewer must be named and their experimental physics background stated.

What gets checked

• Methods section is reproducible — all experimental parameters, equipment specifications, and software tools named with version; a physicist should be able to reproduce the experiment from this section alone
• Discussion addresses discrepancies between the measured and theoretical values — even small discrepancies must be explained; 'close enough' is not a scientific discussion of agreement
• Q&A record shows at least two substantive challenges and responses

Common mistakes

• A discussion that declares agreement with theory without addressing the discrepancy quantitatively — 'our result agrees with theory' when the measured value differs by 5% requires an explanation of whether 5% is within uncertainty and what might explain it
• A reviewer without experimental physics experience — the Q&A must probe data quality and error analysis, which requires experimental expertise

Resources

What a verifier looks for

• Ask the submitter to explain the physical interpretation of the discrepancy between the measured and theoretical values — this is where experimental understanding is demonstrated.
• Ask what the main source of systematic error was and how they estimated its magnitude — quantitative error estimation is the core experimental skill.
• Ask what they would change if they ran the experiment again — tests whether they understood the limitations of their design.