When a solid is heated, it turns directly into a gas. This process is called

Sublimation is the physical process where a substance transitions directly from a solid state to a gaseous state without passing through the intermediate liquid phase [1]. This phase change occurs when the particles in a solid gain enough thermal energy to overcome their intermolecular forces of attraction and escape into the air as vapor [3]. Common examples include solid carbon dioxide (dry ice), which sublimes into a smoky vapor at room temperature, and naphthalene. While evaporation refers to the transition from liquid to gas and condensation is the change from gas to liquid, sublimation specifically describes the direct solid-to-gas conversion [1]. This process is endothermic, meaning it requires the absorption of heat energy to occur. In the natural water cycle, sublimation is observed when snow or ice turns directly into water vapor under specific conditions like low humidity and dry winds [2].

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 24: Hydrological Cycle (Water Cycle) > 24.3. Condensation > p. 329
2. [3] https://www.usgs.gov/water-science-school/science/sublimation-and-water-cycle
3. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > hydrological cyclE. > p. 23