Specific Heat Capacity - Specific Heat Capacity of Solids and Liquids

Every substance has a unique ability to absorb or release heat energy. This property is called specific heat capacity. Here's a classic experiment that reveals it:

Take 1 kg of water and 1 kg of paraffin oil. Heat each with the same heater for the same duration. The paraffin's temperature rises roughly twice as much as the water's — even though both received identical heat energy. This tells us that different substances need different amounts of heat to undergo the same temperature change.

Fig.: Same heat energy supplied, but paraffin oil shows roughly double the temperature rise compared to water.

Specific heat capacity is defined as the amount of heat per unit mass absorbed or given out by the substance to change its temperature by one unit (one degree) 1 °C or 1K.

s = \[\frac {ΔQ}{(m · ΔT)}\]

Where,

The table below lists specific heat capacities at room temperature and atmospheric pressure. Notice how water dominates — about 10× higher than most metals.

Fig.: Visual comparison: Water's specific heat capacity towers above all metals and most liquids.

When the amount of substance is measured in moles (μ) instead of kilograms, we use molar specific heat capacity (C):

C = \[\frac {1}{μ}\] · \[\frac {ΔQ}{ΔT}\]

SI Unit: J · mol⁻¹ · K⁻¹

Fig.: Specific heat capacity at work in everyday life: from car engines to climate patterns.

• Automobile Radiators: Water absorbs a lot of engine heat with only a small rise in temperature because it has a high specific heat.
• Hot Water Bags: Water stores heat for a long time, so hot water bags stay warm longer.
• Cooking (Water vs Oil): Oil heats food faster than water because it has a lower specific heat.
• Coastal Climate: Oceans heat and cool slowly, so coastal areas have moderate temperatures.
• Desert Climate: Sand heats and cools quickly, causing very hot days and cold nights.

• Specific heat capacity (s) measures how much heat per unit mass is needed to change a substance's temperature by 1°C (or 1 K).
• Formula: ΔQ = m · s · ΔT — applies only when there is no phase change.
• Water has the highest specific heat (4186 J/kg·K) among common substances — this is why it's used in cooling systems and retains heat well.
• Molar specific heat (C) measures heat per mole. For gases, it splits into Cₚ (constant pressure) and Cᵥ (constant volume), with Cₚ > Cᵥ always.
• Specific heat is intrinsic; it depends on the material, not on the amount of substance taken.
• The concept explains everyday phenomena such as coastal climate moderation, engine cooling, cooking times, and therapeutic hot water bags.