Specific Heat Capacity
Specific heat capacity (symbol c) is the amount of heat energy required to raise the temperature of one kilogram of a substance by one degree Kelvin (or one degree Celsius). It is an intrinsic material property that reflects how strongly a substance resists temperature change when heat is added or removed. Water has an exceptionally high specific heat capacity (4186 J kg⁻¹ K⁻¹), which makes it an effective thermal buffer in climatic systems, industrial cooling, and biological organisms.
Key Formula
c = Q / (m × ΔT)
LaTeX: c = \frac{Q}{m \Delta T}
| Symbol | Meaning | Unit |
|---|---|---|
| c | Specific heat capacity | J kg⁻¹ K⁻¹ |
| Q | Heat energy transferred | J |
| m | Mass of substance | kg |
| ΔT | Change in temperature | K or °C |
Worked Example
Problem
A 0.5 kg block of aluminium absorbs 9000 J of heat and its temperature rises from 25 °C to 65 °C. Calculate the specific heat capacity of aluminium.
Solution
Step 1: Identify variables: m = 0.5 kg, Q = 9000 J, ΔT = 65 - 25 = 40 °C = 40 K. Step 2: Apply c = Q / (m × ΔT). c = 9000 / (0.5 × 40) = 9000 / 20 = 450 J kg⁻¹ K⁻¹.
Answer
c = 450 J kg⁻¹ K⁻¹ (matches the accepted value for aluminium)
Specific Heat Capacities of Common Substances
| Substance | Specific Heat Capacity (J kg⁻¹ K⁻¹) | State | Application |
|---|---|---|---|
| Water | 4186 | Liquid | Cooling systems, climate regulation |
| Ice | 2090 | Solid | Cold packs, refrigeration |
| Aluminium | 900 | Solid | Cookware, heat sinks |
| Iron / Steel | 450 | Solid | Engine parts, railways |
| Copper | 385 | Solid | Electrical wiring, heat exchangers |
| Air (dry) | 1005 | Gas | HVAC, aerodynamics |
Interactive Tools
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Related Terms
Heat (thermodynamics)
Heat is the transfer of thermal energy between two objects or systems due to a temperature difference; it always flows spontaneously from a region of higher temperature to a region of lower temperature until thermal equilibrium is reached. Unlike temperature (a state property), heat is a process quantity — it only exists as energy in transit, not stored within a body. Heat transfer occurs via three mechanisms: conduction (direct molecular contact), convection (fluid movement), and radiation (electromagnetic waves), and it is measured in joules (J) in the SI system.
Latent Heat
Latent heat is the heat energy absorbed or released by a substance during a phase change (such as melting, freezing, boiling, or condensing) at constant temperature and pressure. The word "latent" means hidden — the energy goes into breaking or forming intermolecular bonds rather than raising the temperature, so the temperature remains constant throughout the transition. There are two principal types: latent heat of fusion (solid ↔ liquid) and latent heat of vaporisation (liquid ↔ gas), and water's exceptionally high latent heat of vaporisation (2.26 MJ kg⁻¹) is critical to weather systems and evaporative cooling.
Thermal Energy
Thermal energy is the total internal kinetic energy associated with the random translational, rotational, and vibrational motion of all particles (atoms and molecules) within a substance. It is a state property stored within a system, proportional to both the temperature and the number of particles present. Thermal energy is the source of heat flow when a temperature difference exists, and it underpins all thermodynamic processes including phase changes, chemical reactions, and the operation of heat engines.
From Latin "specificus" (particular to a kind) and "calor" (heat) + "caput" (head/measure). The term was introduced by the Scottish chemist Joseph Black in the 1760s, who performed careful calorimetric experiments distinguishing the "capacity for heat" among different materials.