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Sublimation is "the process by which a substance goes directly from the solid state to the gaseous state withour passing through the liquid state".
 

Fig. 1: Transfer a paper with a thin layer of water into the freezer. At a temperature of -14.2 ° C the water quickly changes into ice. Mark its outlines on the millimeter paper.
Fig.2: Three weeks later the ice has disappeared from the paper without a trace: It has escaped to the air.