Plan the investigation
What students will do
Start with a guided comparison, then plan an investigation, analyze a graph, and check a prediction.
- Compare masses. Keep pendulum length and release angle fixed. Time three complete oscillations for different bob masses.
- Design and collect. Choose at least five pivot-to-center lengths and plan consistent timing while keeping mass and small release angle fixed.
- Linearize the period data. Transform the period–length relationship and fit a straight line. Determine gravitational acceleration from its slope.
- Explain and predict. Evaluate the effects of mass and length, then predict and test the period for an unused length.
What students will learn
- Measure a period using repeated complete oscillations.
- Test the small-angle length dependence of a pendulum.
- Use a graph to infer gravitational acceleration.
Common misconception
Does doubling length double the period?
Students test the square-root dependence by transforming their period data.