Writing & Language
To show how a common desk fan cools a person, Rhett Allain, a physics professor and writer for Wiredmagazine, performed a simple experiment. He wet apaper towel with warm water and wrapped it arounda thermometer. Allain wrapped a secondthermometer in a dry paper towel. Afterward, heset both thermometers in front of a fan. Initially the fan was turned off. The temperature ofthe thermometer wrapped in the wet paper towel decreased -- at first rapidly, then moreslowly -- and eventually dropped below room temperature. After the fan was turned on, thetemperature of the wet thermometer underwent another rapid decrease. By contrast, thetemperature of the thermometer wrapped in the dry paper towel barely changed during theentire experiment. This experiment demonstrated the power of evaporation to cool wetobjects, such as a sweaty person, and the role of a fan in making evaporation more effective.
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