Well it is going from a solid straight to a gas {example} Dry ice it does not melt it just goes poof in the air slowley
The opposite of sublimation is deposition. Sublimation is the process of a substance changing from a solid directly to a gas, while deposition is the process of a substance changing from a gas directly to a solid.
It is a physical change, the substance stay the same elements before and after the change, this is the same for all states of matter changes (melting, freezing, evaporating, condensing, and sublamation)
Sublimation is the process in which a substance transitions directly from a solid to a gas without passing through the liquid phase. This occurs when the vapor pressure of the solid exceeds the atmospheric pressure at a certain temperature. Sublimation is commonly observed in substances such as dry ice (solid carbon dioxide) and iodine.