Sublimation is the process where a solid substance transitions directly into a gas without passing through a liquid state.
This occurs when two very important magnitudes, temperature and pressure of the substance, reach a specific point known as the sublimation point.
During sublimation, the substance absorbs heat energy from its surroundings, causing its particles to gain enough energy to overcome the attractive forces holding them together as a solid. This results in the particles breaking free and becoming a gas, without ever becoming a liquid.