The difference between temperature and heat lies in their definitions: temperature is a measure of the average kinetic energy of particles in a substance, while heat refers to the transfer of energy between substances due to a temperature difference. Temperature quantifies how hot or cold an object is, influencing physical properties like state and pressure, while heat is the energy that flows from warmer to cooler objects when they are in contact. This distinction is crucial in the study of thermodynamics and energy transfer processes, helping to understand energy conservation and transformations.