Sublimation is the process where a solid changes directly into a gas without first becoming a liquid. This occurs when the molecules in the solid gain enough energy to break free from their fixed positions and enter the gas phase. Common examples of sublimation include dry ice (solid carbon dioxide) turning into carbon dioxide gas and snow gradually disappearing on a sunny day. This phenomenon is often used in various applications, such as freeze-drying food, where moisture is removed by sublimation, preserving the food's structure and nutrients. Sublimation is also important in the field of chemistry and physics for understanding phase transitions.