What phenomenon describes a liquid turning into gas at the surface at any temperature below boiling?

The phenomenon that describes a liquid turning into gas at the surface at any temperature below its boiling point is evaporation. This process occurs when molecules at the surface of a liquid gain enough energy to overcome the intermolecular forces holding them in the liquid state, allowing them to escape into the gaseous phase.

Unlike boiling, which requires the entire body of liquid to reach a specific temperature for bubbles to form throughout the liquid, evaporation can happen at any temperature. It is driven by factors such as temperature, surface area, and the presence of air. As temperature increases, more molecules acquire the necessary energy to evaporate, making the process more rapid, but it does not rely on the liquid reaching its boiling point.

Understanding evaporation is important for explaining various natural phenomena, such as drying clothes or the way puddles disappear. The other options pertain to different processes: condensation refers to gas turning into a liquid, boiling is the rapid phase change from liquid to gas at a specific temperature, and radiation deals with energy transfer via electromagnetic waves, not phase changes.