Wet bulb thermometer

WET BULB THERMOMETER
A thermometer used to measure the lowest temperature in the ambient atmosphere in its natural state by evaporating water from a wet muslin-covered bulb of a thermometer.

WET BULB THERMOMETER: A thermometer with a muslin-covered bulb which is moistened; used to measure wet-bulb temperature.
WIND DIRECTION: The direction from which the wind is blowing. Usually measured in degrees azimuth.

Why does the wet bulb thermometer register a lower temperature than the dry-bulb thermometer?

Wet Bulb Temperature: The temperature obtained from a wet bulb thermometer to obtain the water vapor content (Relative Humidity) of the atmosphere.
Wet Bulb Thermometer: A thermometer covered with muslin to measure wet-bulb temperature.

The final temperature attained by the wetted muslin covered wet bulb thermometer of a psychrometer when thoroughly ventilated.

The evaporation of water from the thermometer has a cooling effect, so the temperature indicated by the wet bulb thermometer is less than the temperature indicated by a dry-bulb (normal, unmodified) thermometer.

type consists of two liquid-in-glass thermometers, one a dry bulb and another, with a muslin sock over the tip which is saturated with water, called the wet bulb. The thermometers are ventilated to cause evaporation off the wet bulb thermometer.

See also: Thermometer, Temperature, Air, Water, Humidity