GCSE Physics revision

Density of materials

Changes of state and the particle model

AQA 4.3.1.1

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AQA student objectives

Learning pathway

ALL 🎯

Recognise/draw simple diagrams to model the difference between solids, liquids and gases.

MOST 🎯🎯

Apply the scientific explanation of density of materials to a relevant example.

SOME 🎯🎯🎯

Analyse a new situation involving density of materials and explain the scientific reasoning.

Revision summary

Read on screen, then print for Cornell-style active revision.

To find an unknown quantity, rearrange the density equation using the formula triangle.
m
To calculate volume, rearrange to V = ρ .
For example, 420 kg of aluminium (density = 2,710 kg/m³)
420 has a volume of 2710 = 0.155 m3 .

To find the density of a solid experimentally, you must first measure both its mass and its volume.
Mass is measured simply by placing the solid object on a balance and recording the reading in kilograms or grams.

If a solid has a regular shape (e.g. a cube or cuboid), its volume can be found by measuring and multiplying its length, width, and height.
For example, a cuboid measuring 4 cm × 3 cm × 2 cm has a volume of 4 × 3 × 2 = 24 cm3 .

For irregularly shaped solids, a Eureka can filled with water and an empty measuring cylinder are used to find the volume.
The Eureka can has a side outlet, so when the solid is submerged, it displaces water equal to its own volume, which flows into the measuring cylinder.
The volume of water collected in the measuring cylinder equals the volume of the irregular solid.

4. Finding the Volume of an Irregular SolidAQA

For irregularly shaped solids, a Eureka can filled with water and an empty measuring cylinder are used to find the volume.
The Eureka can has a side outlet, so when the solid is submerged, it displaces water equal to its own volume, which flows into the measuring cylinder.
The volume of water collected in the measuring cylinder equals the volume of the irregular solid.

To find the density of a liquid, place an empty measuring cylinder on a balance and zero (tare) the balance.
Pour a known volume of liquid (e.g. 10 ml = 10 cm³) into the cylinder and record the mass shown on the balance.
Divide the measured mass by the volume to calculate the density of the liquid using ρ = m V
.

5. Finding the Density of a LiquidAQA

To find the density of a liquid, place an empty measuring cylinder on a balance and zero (tare) the balance.
Pour a known volume of liquid (e.g. 10 ml = 10 cm³) into the cylinder and record the mass shown on the balance.
Divide the measured mass by the volume to calculate the density of the liquid using ρ = m V
.

Using a larger volume of liquid when measuring density reduces the effect of measurement uncertainty, improving accuracy.
Taking multiple measurements allows you to identify anomalous results and calculate a mean value for greater reliability.