Specific Heat Capacity
Definition
How much heat energy it takes to raise 1 kg of a substance by 1 degree — water needs a lot, metals need very little.
Symbol: · Unit: joules per kilogram-kelvin (J/(kg·K))
Technical definition
The heat required per unit mass per unit temperature change, c = Q/(mΔT), measured in J/(kg·K). It reflects how a material stores thermal energy in its molecular motions and bonds.
Example
Water's specific heat is 4186 J/(kg·K) — heating 1 kg of water by 1°C takes the same energy as heating about 9 kg of iron. That is why coastal cities have mild climates: the ocean soaks up summer heat and releases it in winter.
Specific heat is not the same as heat capacity or thermal conductivity. Heat capacity (C = mc) is for a particular object; specific heat (c) is per kilogram of the material. And high specific heat does not mean fast heating — quite the opposite: water heats slowly precisely because its specific heat is huge, which students often get backwards.