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. Drop the ball from the same height with different masses. Compare distances fallen after the same elapsed time.
- Design and collect. Choose a fixed mass and at least five measurement times. Plan how to calculate distance fallen from vertical position.
- Linearize the data. Choose graph quantities that form a straight line. Use its best-fit slope to determine gravitational acceleration.
- Explain and predict. Evaluate the distance–time relationship, then predict and measure the distance fallen at an unused time.
What students will learn
- Distinguish vertical position from distance fallen.
- Test the effect of mass on free-fall motion.
- Linearize a quadratic relationship and estimate gravitational acceleration.
Common misconception
Does doubling fall time double distance fallen?
Students test the time dependence using transformed data and a prediction from their fitted line.