| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Describe how to determine the density of a liquid, of a regularly shaped solid and of an irregularly shaped solid which sinks in a liquid (volume by displacement), including appropriate calculations |
Learning Objective/s:
- Describe the method for determining the density of a liquid, a regular solid, and an irregular solid that sinks.
- Apply the formula ρ = m⁄V to calculate density from measured mass and volume.
- Perform accurate measurements with appropriate equipment and record data using correct units and uncertainties.
- Analyse sample calculations and identify common sources of error.
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Materials Needed:
- Graduated cylinders (various sizes)
- Digital balance
- Ruler or vernier calipers
- Sample liquids (e.g., water) and solid objects (regular block, irregular stone)
- Worksheets with calculation tables
- Projector and screen for demonstration
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Introduction:
Begin with a quick demonstration: pour water into a graduated cylinder and drop a stone, asking students what they notice about the water level. Recall that density links mass and volume, a concept they used in previous lessons on mass‑volume relationships. Explain that today they will learn how to measure density for liquids, regular solids and irregular solids that sink, and will be able to calculate it accurately.
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Lesson Structure:
- Do‑now (5') – students complete a short worksheet converting given mass and volume data to density.
- Mini‑lecture (10') – review ρ = m⁄V, units, and measurement techniques for liquids and regular solids.
- Lab Part A (15') – groups measure a known volume of liquid, weigh it, and calculate its density.
- Lab Part B (15') – groups measure dimensions of a rectangular block, compute its volume, weigh it, and calculate density.
- Lab Part C (15') – groups use the displacement method to find the volume of an irregular solid that sinks, then calculate its density.
- Whole‑class discussion (10') – groups share results, compare calculations, and discuss common pitfalls.
- Exit ticket (5') – each student writes the three steps needed to determine the density of an irregular solid.
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Conclusion:
Summarise that density can be found by measuring mass and volume, whether volume is measured directly, calculated geometrically, or obtained by water displacement. Remind students to keep units consistent and to record uncertainties. For homework, assign a set of practice problems requiring density calculations for different materials.
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