Science
What is Evaporation?
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.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains evaporation.
Key things to understand
- 1Evaporation happens at a liquid's surface, at temperatures below boiling.
- 2The most energetic surface particles break free and escape as vapour.
- 3Heat, wind, dry air, and more surface area all speed evaporation up.
- 4Because the fastest particles leave, evaporation cools the liquid left behind — why sweating cools you.
- 5Evaporation is a key step in the water cycle, lifting water into the air to form clouds.
Frequently asked questions
- 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.