dry-bulb thermometer

instrument

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Last updated

July 17, 2026

Quick Summary

A dry-bulb thermometer is a standard thermometer that measures the ambient air temperature. Its bulb is kept dry, unlike a wet-bulb thermometer, which has a moist cloth covering its bulb to measure cooling due to evaporation. The dry-bulb thermometer registers the temperature based on the liquid's known expansion rate.12

The difference between the readings of a dry-bulb and a wet-bulb thermometer is crucial for calculating relative humidity and dew point. When air is fully saturated, the readings from both thermometers will be the same.12

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hygrometer
…two thermometers—one wet-bulb and one dry-bulb—to determine humidity through evaporation. A wetted cloth wraps the wet-bulb thermometer at its enlarged end. By rapidly rotating both thermometers, or by blowing air over the bulbs, the temperature of the wet-bulb thermometer is cooler than that of the dry-bulb thermometer. The difference in…
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…two thermometers—one wet-bulb and one dry-bulb—to determine humidity through evaporation. A wetted cloth wraps the wet-bulb thermometer at its enlarged end. By rapidly rotating both thermometers, or by blowing air over the bulbs, the temperature of the wet-bulb thermometer is cooler than that of the dry-bulb thermometer. The difference in…
Read More