What is the process called when vapor changes directly into a solid?

• A. Vaporization
• B. Sublimation
• C. Deposition
• D. Condensation

Answer: (C)

The process in which vapor changes directly into a solid is known as deposition. During deposition, gas particles lose energy and transition directly into a solid form without first becoming a liquid. This process is commonly observed in nature, for example, when frost forms on surfaces on cold mornings; the water vapor in the air changes directly to ice without first becoming liquid water.

Understanding this concept involves recognizing how different phases of matter interact under varying temperature and pressure conditions. This phase change is crucial in many scientific applications, including meteorology and materials science. The other options refer to different processes: vaporization describes the transition from liquid to vapor; sublimation refers to the direct change from solid to vapor; and condensation indicates the change from vapor to liquid. Each of these processes has distinct characteristics and definitions, which highlights the importance of accurately naming the process based on the phase changes observed.