Sling Psychrometer

A Sling Psychrometer is a portable humidity measuring instrument that consists of two alcohol-filled thermometers: a dry bulb thermometer and a wet bulb thermometer. It is used to determine relative humidity and other atmospheric moisture parameters.

The instrument is rotated or "slung" through the air. The wet bulb thermometer, covered with a moist wick, cools due to evaporation, while the dry bulb measures the ambient air temperature. The difference between the two readings is used to calculate relative humidity.

Alcohol is a safe, mercury-free liquid that provides reliable temperature measurements and performs well at lower temperatures. It is environmentally friendly and widely accepted for educational and industrial use.

Typically, the Sling Psychrometer should be rotated for approximately 30–60 seconds or until the wet bulb temperature stabilizes.

No. A Sling Psychrometer is a completely mechanical instrument and requires no batteries or electrical power.

The measurement range depends on the model, but most alcohol-filled psychrometers operate within -10°C to +50°C or similar ranges.

Quality alcohol-filled Sling Psychrometers generally offer temperature accuracy of approximately ±1°C, depending on calibration and usage conditions.

An Alcohol-Filled Sling Psychrometer is a dependable, cost-effective, and environmentally safe solution for humidity measurement. Its simple design, portability, and battery-free operation make it ideal for fieldwork, educational purposes, and industrial environmental monitoring.