Physics required practicals

Density of materials

AQA 4.3 · RP5

GCSE Physics (8463) · Required practical 5 — method, variables, the marks examiners report students losing.

Verified against AQA 8463 (2026 spec)

Determine the densities of regular solids, irregular solids and liquids using density = mass / volume, finding volume from dimensions or by displacement.

Apparatus

  • Balance to measure mass
  • Ruler or vernier calipers (for regular solids)
  • Displacement (eureka) can and measuring cylinder (for irregular solids)
  • Measuring cylinder (for liquids)
  • The objects and liquids being tested

Method

  1. 1Regular solid: measure the mass on a balance, measure its dimensions with a ruler, and calculate the volume from the dimensions.
  2. 2Irregular solid: measure the mass, fill a displacement can to the spout, lower the object in and collect the overflow water; the volume of water collected equals the object's volume.
  3. 3Liquid: measure the mass of an empty measuring cylinder, add a known volume of the liquid and reweigh; the liquid's mass is the difference.
  4. 4In every case calculate density = mass / volume.

Results & processing

  • Calculate density = mass / volume, in g/cm3 or kg/m3.
  • Volume from a displacement can equals the volume of water pushed out; read the measuring cylinder at eye level, at the bottom of the meniscus.

Where students lose marks

Not filling the displacement can to the spout first.

Fix: Fill to the spout and let it stop dripping before adding the object, or the collected volume is wrong.

Parallax error reading the measuring cylinder.

Fix: Read the bottom of the meniscus with your eye level with the scale.

Forgetting to subtract the container's mass for a liquid.

Fix: Mass of liquid = (cylinder + liquid) − empty cylinder; only the liquid's mass goes into density = mass / volume.

Improve the method

  • Zero (tare) the balance before measuring mass.
  • Use vernier calipers for small regular objects to measure dimensions precisely.
  • Repeat measurements and take a mean.

Try it — exam-style

Easy
2 marks
ORIGINAL

A regular metal block has a mass of 240 g and a volume of 30 cm3. Calculate its density.

Medium
3 marks
ORIGINAL

Describe how you would find the volume of an irregularly shaped stone.

Questions are written in the style of past AQA papers — never copied from them.

Drill it properly

Physics equations

density = mass / volume and the rest of the AQA equation list.

AQA GCSE Physics flashcards

Density, the particle model and states of matter, drilled.

Stuck on density of materials?

Density marks are lost on the displacement method and unit choice, not the formula — I drill the technique until it's automatic, and your first lesson is free.

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