The History Of Digital Thermometers

The History of Digital Thermometers
The earliest thermometer was invented in 1593 by Italian scientist Galileo (1564-1642). His first thermometer was an open glass tube with a bulb the size of a walnut at the other end. When in use, heat the glass bubble first, and then insert the glass tube into the water. As the temperature changes, the water surface in the glass tube will move up and down, and the temperature change and the temperature can be determined according to the amount of movement. Thermometers have the effect of thermal expansion and cold contraction, so this kind of thermometer is greatly affected by environmental factors such as external atmospheric pressure, so the measurement error is large.
Later, Galileo's students and other scientists made repeated improvements on this basis, such as turning the glass tube upside down, putting liquid in the tube, sealing the glass tube, etc. What stands out is the thermometer made by the Frenchman Brio in 1659. He reduced the volume of the glass bubble and changed the temperature measuring substance into mercury. Such a thermometer already has the prototype of a thermometer. Later, the Dutchman Fahrenheit used alcohol in 1709 and mercury as a measuring substance in 1714 to make a more accurate thermometer. He observed the boiling temperature of water, the temperature when water and ice are mixed, and the temperature when brine and ice are mixed; The temperature of water is set at 32℉, and the temperature at which water boils under standard atmospheric pressure is set at 212℉, and Fahrenheit is represented by ℉. This is the Fahrenheit thermometer.
At the same time as the Fahrenheit thermometer appeared, the Frenchman Lemuel (1683-1757) also designed and manufactured a thermometer. He believed that the expansion coefficient of mercury was too small to be used as a temperature measuring substance. He devoted himself to the study of the advantages of using alcohol as a temperature measuring substance. He found through repeated practice that the volume of alcohol containing 1/5 of water increases from 1000 volume units to 1080 volume units between the freezing temperature and boiling temperature of water. Therefore, he divided the freezing point and the boiling point into 80 parts and determined it as the temperature scale of his own thermometer. This is the Riehl thermometer. ?
After more than 30 years after the Fahrenheit thermometer was made, the Swedish Celsius improved the scale of the Fahrenheit thermometer in 1742. He set the boiling point of water as 0 degrees and the freezing point of water as 100 degrees. Later, his colleague Schlemmer reversed the values of the two temperature points again, and it became the percentage temperature, that is, the Celsius temperature, expressed in ℃. The relationship between Fahrenheit and Celsius is
℉=9/5℃+32, or ℃=5/9(℉-32).
Digital Thermometer
Digital Thermometer
Britain and the United States mostly use Fahrenheit, Germany mostly uses Liechtenstein, and most countries such as my country and France mostly use Celsius in the world's scientific and technological circles, industrial and agricultural production.