ACT (Enhanced)ScienceMedium
A student is investigating the relationship between the mass of a pendulum bob and its period (time for one complete swing). They conduct an experiment using three different masses (10g, 20g, 30g) while keeping the length of the pendulum string and the release angle constant. For each mass, they measure the time for 20 oscillations and then calculate the average period. Which of the following is a potential source of experimental error that could affect the accuracy of the results?
- AInconsistent release angle for the pendulum.
- BKeeping the length of the string constant.
- CMeasuring the time for 20 oscillations instead of 1.
- DUsing different masses for each trial.
Show answer & explanationAnswer & explanation
Correct answer: A. Inconsistent release angle for the pendulum.
An inconsistent release angle would change the amplitude of the swing, which can affect the period of a simple pendulum, especially at larger angles, thereby introducing variability and error into the measurements for each mass.
Why the other options are wrong
- B. Keeping this constant is good experimental practice (a controlled variable), not a source of error.
- C. Measuring 20 oscillations and averaging helps reduce the human reaction time error for a single swing, improving accuracy, not decreasing it.
- D. This is the independent variable, which is intentionally changed, not an error.
Experimental Error
Discrepancies between measured values and the true value, arising from limitations in measurement or experimental design.
- Can be systematic (consistent, reproducible) or random (unpredictable).
- Minimizing error improves accuracy and reliability of results.
- Often results from uncontrolled variables or faulty equipment.
Memory trick: Error: 'E' for 'Eek!' - something went wrong.