Clouds form as water vapor undergoes which change of state?

• A. Condensation
• B. Evaporation
• C. Sublimation
• D. Precipitation

Answer: (A)

Clouds form when water vapor cools and changes into liquid, a process called condensation. When the air becomes saturated and reaches its dew point, the water vapor loses enough energy to turn into tiny liquid droplets that cling to microscopic particles in the air. Those countless droplets group together and become visible as a cloud. Evaporation would be liquid turning into vapor, which would increase atmospheric moisture rather than create the liquid droplets of a cloud. Sublimation is solid turning directly into gas, not part of the typical cloud-formation process. Precipitation is what happens after clouds have formed and droplets grow too large, causing them to fall as rain or snow.