When a system is heated and its temperature rises, the size of the rise depends on three things: the mass of the substance heated, the type of material, and the energy input to the system. A bigger mass needs more energy for the same temperature rise, and different materials need different amounts of energy.
The specific heat capacity of a substance is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius. It is measured in joules per kilogram per degree Celsius, J/kg °C. Water has a high specific heat capacity of about 4200 J/kg °C, so it takes a lot of energy to warm it up. A material with a low specific heat capacity heats up quickly. For the same mass and the same energy supplied, the material with the larger specific heat capacity has the smaller temperature rise, because it needs more energy for each degree.
The change in thermal energy is calculated with: change in thermal energy = mass × specific heat capacity × temperature change, or E = m c Δθ. The energy E is in joules (J), the mass m is in kilograms (kg), the specific heat capacity c is in J/kg °C and the temperature change Δθ is in °C.
Worked example: 2.0 kg of water is heated by 10 °C. E = 2.0 × 4200 × 10 = 84000 J. For the same mass of water, doubling the energy doubles the temperature rise.