Density. Measure it.

Method A — Regular solid:

1. Use vernier callipers (or a metre rule) to measure length l, width w, height h.
2. Calculate volume V = l × w × h.
3. Place the solid on a tared digital balance to find mass m.
4. Calculate density ρ = m / V.

Method B — Irregular solid (water displacement):

1. Pour water into a measuring cylinder; record the initial volume V₁ at the meniscus.
2. Tilt the cylinder and slide the solid down the inner wall to avoid splash.
3. Record the new volume V₂.
4. Volume of solid = V₂ − V₁.
5. Find mass on a tared balance; compute ρ = m / (V₂ − V₁).

Method C — Liquid:

1. Place an empty, dry beaker on the balance and press Tare.
2. Pour the test liquid into the beaker; record mass m.
3. Transfer the liquid to a measuring cylinder; record volume V at the meniscus.
4. Compute ρ = m / V.

• Parallax reading the meniscus — view the bottom of the meniscus at eye level, perpendicular to the cylinder.
• Air drafts on the balance — close any draught shield; press Tare with the empty container in place.
• Floating solid (irregular method) — push down with a known-volume sinker and subtract the sinker's volume.
• Liquid film on the beaker after transfer — use a clean dry cylinder and pour carefully.
• Soluble solid — use a non-reactive liquid such as displacement oil instead of water.

• Digital electronic balance (resolution ± 0.01 g or ± 0.1 g)
• Vernier callipers (± 0.1 mm) or metre rule (± 1 mm)
• Measuring cylinder (100 cm³, resolution ± 1 cm³)
• Displacement (Eureka) can — optional alternative for irregular solids
• Beaker (250 cm³) for liquids
• Sinker (for floating solids)

• 1.4 Density — define density as mass per unit volume; recall and use ρ = m / V.
• 1.4 — describe an experiment to determine the density of a liquid, a regularly shaped solid, and an irregularly shaped solid that sinks in water (both volume and mass must be determined).
• 1.4 — predict whether an object will float or sink based on density data.
• 1.1 Measurement techniques — use a measuring cylinder; read the bottom of the meniscus to avoid parallax.
• Paper 6 — record observations to an appropriate number of significant figures matched to instrument resolution.