Thermal is a type of energy heat is the amount of energy in a system due to the collisions of matter (a glass of 100 degree celsius of water has a lower heat than a pool of 100 degree celsius of water) temperature is the average heat in a system (this is why both the glass of water and pool have the same temperature although they do not have the same amount of heat) heat capacity is the amount of heat needed to raise the temperature by 1 degree celsius or kelvin