When a solid is converted to a liquid, energy must be absorbed. This process is termed as melting.
The reverse process of melting is freezing, where liquid fuses to form a solid. Energy is released in this process.
Evaporation is the conversion of liquid to vapor by absorbing energy.
Sublimation is the direct conversion of solid to vapor state by absorbing energy.
Condensation is the reverse of evaporation. In condensation vapors condense to form liquid releasing energy in the process.
Therefore, the processes that absorb energy are melting, evaporation and sublimation.
