Question:
What is the difference between boiling and evaporation?
Replies:
Boiling is very rapid evaporation starting at the bottom of a container of water.
Evaporation occurs fastest where there is the most heat (energy). When we heat water to
make it boil we heat it from the bottom so the evaporation occurs at the bottom of the
pot. As a result, large bubbles of water vapor form at the bottom and rise to the
surface in the boiling action. If we applied the same heat to the top surface of the
water it would evaporate just as quickly but we would not call it boiling because the
bubbles would not form and rise to the surface.
Normally evaporation occurs at a much slower rate than boiling because most evaporation
occurs with room temperature water.
Greg Bradburn
Evaporation-is the escape of molecules from the liquid state to the gas or vapor state.
In evaporation, molecules of higher-than-average kinetic energy escape from a liquid,
leaving it cooler than it was before they escaped.
Boiling-is the temperature at which the vapor pressure of a liquid is equal to the
external pressure above the liquid. When we give the boiling point of a liquid, we
need also to state the pressure.
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