Melting is the process of a substance changing from a solid to a liquid state. For ice, this occurs at 0°C under standard atmospheric conditions.
Phase Transition: The transformation of matter from one state to another, such as from solid to liquid or liquid to gas.
The amount of energy required to change one gram of a substance from the solid phase to the liquid phase at its melting point.
The branch of physical science that deals with the relations between heat and other forms of energy.