The ubiquitous thermometer is a familiar object in every home. Used to measure body temperature, it is used universally as one of the primary indicators of sickness. Before the thermometer was invented, the physician would check the temperature of a patient by hand.
The first instrument for measuring temperature was invented by Galileo Galilei in 1593. He filled a glass bulb with air and connected it to a long tube of water to show variations in temperature. This instrument was called a thermoscope since a calibration was not present for measuring the temperature.
In 1612, Venetian physician Santorio Santori transformed the thermoscope into a thermometer by adding a numerical scale for measurement. In 1654, an enclosed thermometer was invented by the Grand Duke of Tuscany, Ferdinand II. He used alcohol as the liquid inside.
In 1714, Daniel Gabriel Fahrenheit invented the first precision thermometer. He used mercury instead of alcohol or water. In 1724 he introduced the standard temperature scale ‘Fahrenheit scale’ which was used to record temperature changes accurately. This thermometer was the most accurate till date and was the first to be mass produced. It is still in use today.
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