What is sublimation in terms of phase changes?

Sublimation refers to the process where a solid changes directly into a gas without passing through the liquid phase. In the context of water, this specifically involves ice converting directly into water vapor. This process can occur under certain conditions, such as low pressure and temperature, allowing the solid ice to transition to gas without becoming liquid first.

Sublimation is commonly observed in various natural phenomena, such as snow and ice disappearing in cold, dry climates without melting first. Understanding this phase change is crucial for various meteorological applications, including weather prediction and climate science.

Other processes listed in the choices describe different phase changes: the transformation of gas to liquid indicates condensation, converting liquid water back to ice describes freezing, and the transition of water vapor into clouds involves condensation as well. These processes differ fundamentally from sublimation, which specifically deals with the solid-to-gas transition directly.