The history of temperature measurement has a long and storied past, and it is the result of humanity's continuous exploration and understanding of natural phenomena. In the early days, people could only roughly judge the hotness or coldness of an object through the senses. For example, they used to touch an object with their hands to feel the temperature. However, this method is highly subjective and inaccurate.
In ancient civilizations, some simple methods of temperature perception began to emerge. For instance, the ancient Greeks discovered that air expands when heated, laying the groundwork for the development of temperature measurement tools later. With the accumulation of scientific knowledge, in the 16th century, Galileo invented a primitive thermometer. It utilized the principle of air's thermal expansion and contraction, and the change in temperature was indicated by observing the height change of the air column in a glass tube. However, this thermometer was greatly affected by environmental factors such as air pressure.
In the 17th century, thermometers based on the principle of liquid's thermal expansion and contraction were developed. Fahrenheit proposed the Fahrenheit scale in 1724 and manufactured a more accurate mercury thermometer, providing a more reliable standard for temperature measurement. Subsequently, in 1742, Celsius proposed the Celsius scale, which is widely used in scientific research and daily life. By the 19th century, with the gradual improvement of thermodynamic theory, scientists began to understand the nature of temperature at a theoretical level more deeply, further promoting the development of temperature measurement technology, continuously improving the measurement accuracy and expanding the measurement range.
