What is the process called when ice changes directly to water vapor?

The process in which ice changes directly to water vapor is known as sublimation. Sublimation occurs when a solid transitions directly into a gas without first becoming a liquid. This phase change typically happens under specific conditions, often involving low atmospheric pressure or when the temperature increases significantly. An example of sublimation is when dry ice (solid carbon dioxide) changes directly into carbon dioxide gas.

In contrast, melting refers to the transition of a solid to a liquid, whereas evaporation is the process of a liquid turning into a gas. Condensation, on the other hand, is the reverse process where gas transitions back into a liquid. Understanding these fundamental concepts of phase changes is essential in the study of thermodynamics and environmental science.