Evaporation — Science definition

Defined in 3 courses:

Where it is taught

In use

Evaporation means liquid water changes to gas at its surface; condensation means gaseous water changes to liquid.

Evaporation, Condensation & a Wet Cold Cup

It usually starts with evaporation: the sun's energy heats liquid water, mostly at the wide surface of the oceans, giving the fastest-moving water molecules enough energy to break free and float up into the air as invisible water vapor.

The Water Cycle

Questions using evaporation

Problem 1

Which statement correctly uses evaporation in States of Matter & the Particle Model?
  1. A gas has no mass because it is invisible.
  2. Solid particles are completely motionless.
  3. evaporation: A change from liquid to gas at a surface, possible below boiling.
  4. One illustrative result establishes every real condition and needs no further evidence.
Answer and explanation

evaporation: A change from liquid to gas at a surface, possible below boiling.

A change from liquid to gas at a surface, possible below boiling. Melting in the closed sample changes arrangement while retaining its 50 g of water. The open dish loses 6 g from the measured liquid; evaporation is a possible pathway into the air. The water has not been destroyed. Without further records, the mass loss alone does not exclude a spill or specify the evaporation rate over a particular time.

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