What Is Evaporation?

Science · Matter and Materials · Grades 3–5

Meaning at a glance

Evaporation is when a liquid changes into a gas. In the water cycle, liquid water changes into water vapour, an invisible gas in the air.

Also searched as: evaporate, evaporating, water vapour, water vapor.

Understand it simply

Water is made of tiny particles that are always moving. Heat gives them more energy. Particles at the surface that gain enough energy escape into the air as a gas called water vapour. That change from liquid to gas is evaporation.

Evaporation happens at any temperature below boiling, but it is faster when it is warm, windy and when the water has a large surface.

See it work

After rain, a puddle on the road slowly gets smaller. The water did not vanish. The sun warmed it, and it evaporated into the air as water vapour.

The same thing dries wet clothes on a line and salt in a salt pan. On Earth, most of the water vapour in the air comes from the oceans, seas, lakes and rivers.

Liquid waterpuddle, sea, wet clothHeat from the sungives particles energyWater vapouran invisible gas in the air
Evaporation: liquid water, plus heat, becomes water vapour.

Avoid this confusion

Evaporation is not the same as boiling. Boiling happens when the whole liquid is heated to its boiling point (100°C for water at sea level) and bubbles form. Evaporation happens quietly at the surface at lower temperatures too.

Also, water vapour is invisible. The white cloud above a hot kettle is made of tiny drops of liquid water. It forms when vapour cools, which is condensation.

Try it yourself

Work these out first, then check your answers below.

  1. Why does wet washing dry faster on a hot, windy day than on a cool, still day?

  2. What is the name of the gas that water changes into when it evaporates?

  3. True or false: water must boil before it can evaporate.

Check your understanding

Show the answer to question 1

Answer: Heat and wind speed up evaporation.

Heat gives the water particles more energy to escape. Wind carries the water vapour away so more water can evaporate.

Show the answer to question 2

Answer: Water vapour

Evaporation changes liquid water into the gas water vapour.

Show the answer to question 3

Answer: False.

Water evaporates from its surface at many temperatures. A puddle dries without ever boiling.

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Sources and review

Written by: Courseversity editorial team (AI-assisted draft).

Review status: checked against the sources above. Educator review is pending, so please tell us if anything looks wrong.

Last updated: 27 October 2026.

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