What is the name of the process in which a solid material changes directly into a gas without becoming liquid?

The process in which a solid material changes directly into a gas without becoming liquid is known as sublimation. This phenomenon occurs when the molecules in a solid gain enough energy to overcome the attractive forces holding them together, allowing them to transition directly into the gaseous state. A common example of sublimation is the transition of dry ice (solid carbon dioxide) directly into carbon dioxide gas.

Understanding this process is important because it highlights the energy changes involved and the specific conditions under which sublimation occurs, such as low pressure and temperature. Other processes like evaporation involve a liquid state, while condensation refers to the conversion of gas to liquid, and deposition describes the reverse of sublimation (gas to solid). Hence, sublimation specifically refers to the direct solid-to-gas transition, distinguishing it clearly from the other related processes.