Comparing Heat Capacities of Materials

Different materials require different amounts of energy to raise their temperature by the same amount. This property is quantified by specific heat capacity.

Key values

Material	$c$ (J/(kg $^\circ$C))
Water	4200
Aluminium	900
Copper	390
Iron/steel	450
Lead	130
Glass	840
Oil	2000
Concrete	880

Why water’s high SHC matters

Water has an unusually high specific heat capacity. This means:

• It takes a lot of energy to heat water, but it also releases a lot of energy when it cools.
• Water is used in central heating systems and car cooling systems.
• Coastal regions have more moderate temperatures than inland areas (the sea absorbs and releases thermal energy slowly).
• Water is an effective coolant in power stations and industrial processes.

Comparing heating rates

If two equal masses receive the same energy:

$\Delta\theta = \frac{E}{mc}$

The material with the lower $c$ heats up faster (larger $\Delta\theta$).

Example: 1000 J is supplied to 0.5 kg of water and 0.5 kg of copper.

Water: $\Delta\theta = \frac{1000}{0.5 \times 4200} = 0.48$ $^\circ$C

Copper: $\Delta\theta = \frac{1000}{0.5 \times 390} = 5.1$ $^\circ$C

The copper heats up over 10 times faster.

Common errors and how to correct them

• Confusing “heats up faster” with “has higher specific heat capacity.” A higher SHC means the substance heats up more SLOWLY.

How to apply this in an exam

Use $\Delta\theta = E/(mc)$ to compare temperature changes. Explain the practical consequence in the context of the question.