Concluding in Physics (DP IB Physics): Revision Note

Concluding in Physics

• The conclusion is a brief, focused summary of the findings of your investigation

• Your goal is to provide a clear and concise answer to your research question, based only on the evidence from your data analysis

• A strong conclusion relates your specific findings back to broader physical principles and compares them to accepted values

Principles of concluding

Interpret processed data and analysis to draw and justify conclusions

• Your conclusion must be justified by your data

  • This is the most important rule

• Start your conclusion with a direct answer to your research question

• Use the trend you identified in your interpretation to make a definitive statement

• Include key processed data as evidence to support your statement, such as:

  • the final calculated value for a physical constant (e.g., g)

  • the gradient of your linearised graph

  • the experimental value for a material property (e.g., resistivity)

• Never introduce new ideas or explanations in the conclusion

  • It should only be a summary of what you have already analysed

Relate the outcomes to the stated research question or hypothesis

• You must explicitly state whether your results support or refute your initial hypothesis

  • For example: "The data shows that is directly proportional to , which supports the hypothesis."

• If your results do not support your hypothesis, that is perfectly fine and does not mean your experiment has "failed"

  • It is a valid scientific finding, and you should state it clearly

  • You can then suggest reasons for the discrepancy in your evaluation

Compare the outcomes to the accepted scientific context

• A high-level conclusion compares your experimental results to accepted literature values from the IB data booklet, textbooks, or other reliable sources

• This comparison allows you to comment on the accuracy of your outcome

• When making a comparison, you should:

  • state the literature value

  • cite your source (e.g., "IB Physics Data Booklet, 2025")

  • quantify the difference, usually by calculating the percentage error

Discuss the impact of uncertainties on the conclusions

• Your propagated uncertainty determines the confidence you have in your final result

• You must comment on the significance of your uncertainty

• Compare your percentage uncertainty with your percentage error

  • If the percentage error is larger than the percentage uncertainty:

    • This suggests that the deviation from the literature value is not just due to the limitations of your equipment (random error)

    • The error is likely due to significant systematic errors in your methodology

  • If the literature value falls within the range of your experimental uncertainty:

    • You can conclude that your result is consistent with the accepted value, despite any errors

    • For example, your result is 9.8 ± 0.2 m s^-2 and the true value is 9.81 m s^-2