Why does wet skin feel chilly?

Ask Tom Why
This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

Dear Tom,
Why does wet skin feel chilly?
Lynn Malfort, Chicago
Dear Lynn,
It is a characteristic of every substance that the molecules of which the substance is composed vibrate. What we call “temperature” is actually a measure of the average vibrational energy contained by the molecules of the substance. We perceive the molecular vibration as the sensation of heat. When a liquid (like water) is heated, its molecules vibrate more rapidly and its temperature rises. But the vibrational motion of water molecules actually consists of a spectrum of speeds: Some molecules are moving less rapidly than the average speed and some are moving more rapidly. The fastest molecules, if they possess enough energy, will break through the water’s surface — they evaporate. This leaves the remaining liquid with a lower average energy content. Consequently, evaporation is a cooling process.


Latest News

More News