When a liquid evaporates, it transforms into a gas and disappears into the air. After a rainstorm, puddles on the sidewalk gradually shrink and vanish as the water evaporates. The water doesn't truly disappear: it turns into an invisible gas called water vapor and mixes with the air around us.

Heat speeds up evaporation. That's why wet hair dries faster on a sunny day than in a cold room, and why your mom might hang laundry outside to dry in the summer. The sun's warmth gives water molecules enough energy to break free from the liquid and float away as vapor.

The word also describes things that vanish or disappear suddenly. When a basketball team falls far behind, you might say their chances of winning have evaporated. If you were confident about remembering your lines in the school play but then your mind goes blank on stage, your confidence might evaporate in an instant. A crowd might evaporate after a concert ends, with people scattering in all directions until the area is empty.

Scientists call the reverse process condensation: when water vapor in the air cools down and turns back into liquid droplets, forming dew on grass or fog in the morning air.