The process by which a solid changes directly into gas is called:
Sublimation
Sublimation is a specialized change of state when a solid substance skips the liquid phase and moves directly into the gas phase. This occurs because the substance absorbs energy so quickly from the surroundings that melting never occurs.
Examples of Sublimation:
1. "Dry ice" or solid carbon dioxide sublimes.
2. Snow and ice can sublime in the winter months without melting.
3. Moth balls sublime
4. Frozen foods will sublime and you will find ice crystals inside of the box or bag.