When is evaporation fastest?

Correct answer: High temperature and dry air

Correct answer: C, high temperature and dry air. Evaporation is the change of liquid water into water vapour from a surface. Heat gives water molecules more energy, so more molecules can escape into the air. Dry air contains less water vapour and has more capacity to receive additional vapour, so evaporation continues quickly. A is wrong because low temperature reduces molecular energy and high humidity makes the air closer to saturation. B is wrong because enclosed, still air often becomes humid near the surface, slowing further evaporation. D is generally wrong because a cold surface at night provides less heat and evaporation is usually slower. C combines the two favourable conditions: strong heating and low humidity. Wind can also increase evaporation by replacing moist air, but the best option here is specifically high temperature and dry air. Memory cue: heat starts evaporation; dry air allows it to continue.