The process of converting a solid directly to a gas without passing through the liquid state is called sublimation. This transition occurs under specific conditions of temperature and pressure. Sublimation is commonly observed in substances like dry ice (solid carbon dioxide), which turns directly into carbon dioxide gas at room temperature and atmospheric pressure. Other examples include the sublimation of snow and ice in cold weather, where they appear to disappear without melting into liquid water. This phase change is utilized in various applications, including freeze-drying and certain methods of purification.