Lesson Plan

• Define density and write the formula ρ = m/V with correct units.
• Calculate weight, buoyant force, and pressure using density values.
• Analyse static‑equilibrium situations and determine whether an object will float, sink, or remain suspended.
• Apply the density‑based equations to solve multi‑step physics problems.

• Projector and screen
• Whiteboard and markers
• Aluminium cube (0.10 m side) and water container
• Density data handout (water, aluminium, steel, air)
• Calculators
• Worksheet with equilibrium problems
• Balance scales (optional)

Begin with the question “Why does a massive steel ship float?” to spark curiosity. Review students’ prior knowledge of mass, volume, and force. State that by the end of the lesson they will be able to use density to calculate forces and decide if objects are in equilibrium.

1. Do‑now (5'): Quick mental task – list everyday objects that float or sink; discuss the role of density.
2. Direct instruction (10'): Define density, show ρ = m/V, discuss units and typical values; derive W = ρVg, F₍b₎ = ρ₍fluid₎Vg, P = ρ₍fluid₎gh.
3. Demonstration (10'): Measure the aluminium cube, calculate its mass, weight, and buoyant force in water; illustrate static equilibrium (ΣF = 0) with a free‑body diagram.
4. Guided practice (10'): Pairs solve a worksheet problem similar to the example – determine if a wooden block floats in oil.
5. Check for understanding (5'): Exit‑ticket question – “Write the condition for an object to float using density.” Collect responses.
6. Summary (5'): Review checklist of key formulas and concepts; answer any remaining questions.

Summarise how density links mass and volume to forces such as weight and buoyancy, and how these forces determine equilibrium. Students complete an exit ticket stating one condition for floating and receive a homework task to solve two density‑equilibrium problems from the textbook.