Thermal Physics

Heat Capacity (C) The amount of heat energy required to raise the temperature of an entire object by 1 K (or 1 °C). Heat capacity is an extensive property—it depends on the mass and material of the object. For example, a large iron block has a higher heat capacity than a small iron nail, meaning it requires more energy to heat up by the same amount. Specific Heat Capacity (c) The amount of heat energy required to raise the temperature of 1 kg of a substance by 1 K (or 1 °C). This is an intensive property—it depends only on the material, not the mass. Water has a high specific heat (4200 J kg⁻¹ K⁻¹), which is why it takes a long time to boil and is used as a coolant in car engines. Calorimetry Principle In an isolated system, the heat lost by a hot object equals the heat gained by a cold object, assuming no heat exchange with the surroundings. This is a direct application of the conservation of energy. For example, when a hot metal block is placed into cool water in a calorimeter, the metal cools down while the water warms up until thermal equilibrium is reached.