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Science

How does evaporation work?

Evaporation happens when liquid turns into gas at its surface. The fastest-moving molecules near the surface gain enough energy to escape into the air — which is why puddles dry up and wet clothes dry, especially when it's warm or breezy.

See it in motion.
Watch a 2-minute animated lesson that shows exactly how evaporation works.
▶ Watch the visual lesson

Step by step

  • 1Liquid turns to gas at its surface.
  • 2The most energetic surface molecules escape into the air.
  • 3Heat and airflow speed it up.
  • 4It cools the remaining liquid (evaporative cooling).

Frequently asked questions

How does evaporation work?
The fastest-moving molecules at a liquid's surface gain enough energy to escape as gas into the air.
Why does evaporation cause cooling?
The most energetic molecules leave, lowering the average energy — and temperature — of what remains.
What speeds up evaporation?
Higher temperature, more surface area, lower humidity, and moving air all help.

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