Which process changes liquid water into a gas?

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

Answer: (A)

Phase changes are about how matter moves between states, and this question focuses on turning a liquid into a gas. Liquid water becomes gas when it gains enough energy for its molecules to move faster and break free from the surface into the air. That surface-changing process is evaporation, and it can happen at temperatures below the boiling point, especially when the sun heats the surface or the air near the surface is dry or moving. Condensation would be gas turning into liquid, which is the opposite. Precipitation is water falling as rain, snow, or hail. Transpiration is water vapor leaving plant leaves. So evaporation is the process that changes liquid water into a gas.