A psychrometer is one of the most effective instruments used to measure the water vapor content—or the amount of moisture or relative humidity—in the air.

How does it work?

The psychrometer consists of two Celsius thermometer tubes.  The red tube measures the actual ambient temperature—referred to as the dry bulb temperature.  The base of the blue tube is immersed in a vessel containing a muslin wick soaked in water.  This tube measures the temperature caused by the effects of evaporation from the saturated wick.  This temperature reading is referred to as the wet bulb temperature.  The relative humidity (%) of the air is then calculated by crossing the dry bulb and the wet bulb temperature readings on the easy to read chart beneath the tubes.  

Why use the Psychrometer?

  In addition to being one of the most easy and accurate methods of determining the relative humidity, the psychrometer is completely MERCURY-FREE!  Our psychrometer has a dedication to astronomer Anders Celsius (1701 – 1744) printed at the top. The psychrometer is very durable and affordable but its most important feature is that educators can maintain the learning benefits of students seeing the effects of moisture on temperature.  Digital or aneroid substitutes sacrifice the visual physical principles that are evident with liquid instruments. 

Be sure to see our matching acrylic, full size mercury-free liquid barometer, The Eco-celli Model E038

Dimensions of Psychrometer:

Frame size:  16.5 inches long, 4 inches wide.

Made of sturdy acrylic

Celsius thermometers are 9.75 inches long.

Model P1 Suggested Retail Price: $115.00