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What is evaporation?

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Quick answer

Evaporation is the process by which a liquid slowly turns into a gas at its surface, below its boiling point. It happens when the fastest-moving particles at the surface gain enough energy to escape into the air — which is how puddles dry up and wet clothes get dry.

Key things to understand

  1. Evaporation happens at a liquid's surface, at temperatures below boiling.
  2. The most energetic surface particles break free and escape as vapour.
  3. Heat, wind, dry air, and more surface area all speed evaporation up.
  4. Because the fastest particles leave, evaporation cools the liquid left behind — why sweating cools you.
  5. Evaporation is a key step in the water cycle, lifting water into the air to form clouds.

People also ask

What's the difference between evaporation and boiling?
Both turn liquid into gas, but evaporation happens only at the surface and at any temperature, while boiling happens throughout the liquid once it reaches its boiling point.
Why does evaporation cool things down?
The fastest, highest-energy particles are the ones that escape, leaving the slower, cooler particles behind. That lowers the liquid's temperature — the reason sweat cools your skin.
What makes water evaporate faster?
Higher temperature, moving air (wind), low humidity, and a larger surface area all speed it up by helping surface particles escape into the air.

Part of the guide: Water & Weather Phenomena →