Thermometers are tools that can accurately judge and measure temperature, which are divided into pointer thermometers and? Digital thermometer. A variety of thermometers have been designed and manufactured for different purposes.

The earliest thermometer was invented by Italian scientist Galileo (1564 ~ 1642) in 1593. His first thermometer was a glass tube with an opening at one end and a glass bulb the size of a walnut at the other. When in use, the glass bulb is heated first, and then the glass tube is inserted into water.

With the change of temperature, the water surface in the glass tube will move up and down, and the temperature change and temperature level can be judged according to the movement amount. Thermometers expand with heat and contract with cold, so this kind of thermometer is greatly influenced by environmental factors such as external atmospheric pressure, so the measurement error is large.

At the same time as the Fahrenheit thermometer appeared, the Frenchman Lemuel (1683 ~ 1757) also designed and manufactured the thermometer. He thinks that the expansion coefficient of mercury is too small to be used as a temperature measuring material. He focused on the advantages of using alcohol as a temperature measuring substance.

He repeatedly found that the volume expansion of alcohol containing 1/5 water increased from 1000 unit volume to 1080 unit volume between the freezing temperature and boiling temperature of water. So he divided the freezing point and boiling point into 80 parts and set them as the temperature scale of his thermometer, which is Liebherr thermometer.

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