Plan the investigation
What students will do
Start with a guided comparison, then plan an investigation, analyze a graph, and check a prediction.
- Compare immersion levels. Measure support tension with the specimen in air, partly submerged, and fully submerged.
- Design and collect. Choose at least five liquid densities. Keep specimen mass and volume fixed and measure stationary rope tension during full immersion.
- Analyze a graph. Fit rope tension versus liquid density. Determine specimen volume from the slope and interpret the force intercept.
- Explain and predict. Explain apparent weight with a force diagram, then predict and test tension for an unused liquid density.
What students will learn
- Distinguish support-force readings from gravitational weight.
- Explain how immersion and liquid density affect rope tension.
- Use graph slope and intercept to infer specimen volume and weight.
Common misconception
Does gravity become weaker underwater?
Students explain the smaller support reading using buoyancy and the specimen’s unchanged gravitational weight.