What do we call the process of changing a solid directly into a gas?

The process of changing a solid directly into a gas is known as sublimation. This phenomenon occurs without the intermediate stage of becoming a liquid. Sublimation typically occurs under specific conditions of temperature and pressure, and is most commonly observed with substances like dry ice (solid carbon dioxide) and snow under certain atmospheric conditions.

Understanding sublimation is important in various fields, including meteorology, physical chemistry, and practical applications such as freeze-drying food. In contrast, evaporation refers to the process where a liquid transitions into a gas. Condensation is the opposite of evaporation, where gas turns back into a liquid. Melting, on the other hand, is the transition from a solid to a liquid. Recognizing these distinct processes helps in grasping the phases of matter and their transformations.