Evaluation

🧪 CRITERION D: EVALUATION (6 marks total)

✅ 1. Explain the Impact of Methodological Weaknesses

You’re expected to:

• Identify specific issues in your method (not just vague “human error”)

• Explain how each issue may have affected your results

• Reflect on the design, execution, or equipment used

✔️ What to Do:

• Think about problems like:

  • Difficulty in controlling variables (e.g., air resistance, friction)

  • Low measurement precision (e.g., using a ruler instead of a vernier caliper)

  • Inconsistencies in data or trends

  • Manual errors, like timing with a stopwatch

🧠 Example:

“The use of a handheld stopwatch introduced significant human reaction time error, especially for shorter periods. This affected the accuracy of time measurements and likely led to inconsistencies between trials.”

✅ 2. Identify Weaknesses Related to Variables, Precision, or Data Spread

You must be specific about the types of errors or limitations that were present.

✔️ What to Do:

• Comment on lack of control over environmental conditions

• Talk about instrument precision (e.g. ±0.1 s stopwatch vs ±0.01 s sensor)

• Mention range or spread of data (e.g. too narrow a range of values for a strong conclusion)

• Address systematic errors and random errors

🧠 Example:

“Although the experiment controlled for initial angle and mass of the pendulum, ambient air currents and inconsistent release methods likely introduced random variations in the period.”

✅ 3. Provide Realistic and Relevant Improvements

Don’t just say “use better equipment”—suggest feasible, detailed, and realistic changes that could actually be made.

✔️ What to Do:

• Suggest ways to improve precision (e.g., motion sensors, light gates)

• Recommend changes to experimental setup (e.g., fixing the release point more securely)

• Propose better control of variables (e.g., conducting in an enclosed space)

• Consider using more data points or a broader range

🧠 Example:

“Using a photogate timer instead of a manual stopwatch would reduce timing uncertainty and improve the accuracy of the period measurement. Additionally, using a mechanical release mechanism would ensure a more consistent start to each oscillation.”

✅ 4. Explain How Improvements Enhance Reliability and Accuracy

Just suggesting improvements isn’t enough—you need to explain why they matter.

✔️ What to Do:

• Link each suggestion to how it would reduce error, increase consistency, or support better conclusions

• Show you understand the scientific value of refinement and precision

🧠 Example:

“By reducing the uncertainty in time measurements from ±0.2 s to ±0.01 s, the propagated uncertainty in calculated period would decrease substantially. This would allow for a more precise determination of the relationship between period and length.”

✅ Summary Checklist for Criterion D