 # GCSE Physics # Thermodynamics - Equations and Definitions change in thermal energy (J) = mass (kg) × specific heat capacity (J/kg°C) × change in temperature (°C) thermal energy for a change in state (J) = mass (kg) × specific latent heat (J/kg)

Temperature - a measure of the average kinetic energy of the particles in a substance.  It has units degrees Celsius (°C) or degrees Kelvin (K).

Heating - energy transfer between two objects because one is at a higher temperature than the other.

Internal energy - energy contained in a substance which is the sum of all the kinetic and potential energies of the particles within it.

Change of state - a reversible physical change by which intermolecular forces are either overcome or strengthened because of input or output of heating.

Specific Heat Capacity - the energy change involved in increasing or decreasing the temperature of one kilogram of a material by one degree Celsius.  It has units Joules per kilogram per degree Celsius (J/kg°C).

Specific Latent Heat of Fusion - the energy change involved in the change of state of one kilogram of a substance between a solid and a liquid.

Specific Latent Heat of Vaporisation - the energy change involved in the change of state of one kilogram of a substance between a liquid and a gas.    