How did China measure the temperature in ancient times?

Temperature and humidity are two very important concepts in thermodynamics. The change of temperature and humidity changes the shape of objects, but the deformation degree of different substances is different. So the ancients also got a lot of relevant knowledge in this process.

In ancient China, we not only observed and recorded temperature and humidity to a certain extent, but also made some instruments to measure temperature and humidity, which shows the enthusiasm of ancient working people for measuring temperature and humidity.

The concept of cold and hot has existed since ancient times, and the range of temperature difference expressed by the ancients as cold, cool, cool, warm, hot and hot will vary from person to person, which is extremely subjective. Even so, the ancients found some methods to objectively judge the degree of heat and cold.

Before the appearance of thermometers, people usually felt by their own senses. For example, touching an object with your hand can tell whether it is cold or hot, and how hot or cold it is. This tactile sensation method based on body temperature can only judge the temperature difference within a certain range, rather than a specific temperature concept.

And by observing whether the water freezes, we can infer the degree of temperature drop. Such as "Lu Chunqiu? Shen Dalan? Check into the record: "See the ice in the bottle, and know that the world is cold. "This practice has been recognized by later generations.

Huai Nan Zi in the Han Dynasty? In the short training of soldiers, there is almost the same record: "Seeing the water in the bottle, you can know the temperature of the world." This is because, by observing the freezing or melting of water in the bottle, we can really know the change of temperature.

In ancient times, people thought of many insulation methods to preserve natural ice in winter until the next summer. There has been a saying of "Xia Chengbing" since the Zhou Dynasty, but how to make it at that time remains to be verified.

As for the observation and measurement of temperature, there are many methods. In the work of season, body temperature, smelting and pottery making, we have explored a set of methods for observing temperature.

The ancients lacked understanding of the laws of nature and thought that abnormal festivals were a "warning" from heaven to the emperor and his wife for their immoral behavior. Therefore, it is necessary to record festivals and write them into official history books to illustrate good luck and bad luck. At the same time, the ancients also paid more attention to recording the climate conditions on some specific dates, such as the winter solstice.

Since 1 1 century at the latest, officials have been used to recording the daily weather from winter to the next nine days, which is the so-called "nine cold days". During the Ming and Qing Dynasties, people often recorded the weather these days every day.

There are as many as four volumes of ancient and modern books compiled in the Qing Dynasty. Now, we can see the temperature changes of the ancient climate in China from these records. Body temperature is the most constant "thermometer" in ancient times. Because normal people's body temperature is basically the same. The ancient people fully understood this special "thermometer" and applied it to the processing technology of making cheese, lobster sauce, sericulture and tea.

Jia Sixie, an agronomist in the Northern Wei Dynasty, once pointed out that the temperature at which herders make cheese is "timely for the Xiao Nuan of the human body"; He also pointed out that when making lobster sauce, "it is best to keep warm like armpits at a high speed" and "wait with your fingers as warm as armpits".

Chen Fang, an agronomist in Song Dynasty, said: "Water can be neither hot nor cold, but it is like a human body."

Cai Xiang, an expert in tea science in Song Dynasty, once said that tea "is a collection house, wrapped in leaves and baked for two or three days. Fire is often used as human body temperature, and the temperature is humid. If there is more fire, you can't eat tea and cola. "

When talking about the best room temperature for sericulture in the Yuan Dynasty, agronomist Wang Zhen pointed out that sericulturists "need to measure themselves with light clothes: conscious cold makes silkworms cold, adding fire to the fire; Consciously hot, silkworms will also be hot, which is about the amount of fire. "

The ancients also mastered the high-temperature visual inspection technology by observing the flame color of hot objects. The original meaning of the word "temperature" is to observe the flame color of a hot object.

In the process of metal smelting or ceramic firing, craftsmen of all ages used flame color to judge the temperature in the furnace. Therefore, temperature is actually an experienced high-temperature visual inspection technology created by the ancients. Although it has great experience and can't specify the specific value of temperature, it is completely scientific.

The book Flower King Gong Ji in the Warring States Period first recorded the flame color of bronze smelting: in the process of adding copper ore and tin ore to the furnace for smelting, impure impurities first melted and volatilized, and their combustion showed a black flame color; Then, tin or impurity sulfur with low melting point melts and volatilizes, showing yellow-white flame color; With the increase of furnace temperature, copper melts and volatilizes, and copper and tin become bronze alloys, which are blue and white, and can be cast in furnace.

Artisans such as smelting, casting and pottery-making have all used it to observe the temperature, and alchemists and pharmacologists have also developed this method.

The ancients left us a lot of records about the color of matter flame. These records show that judging the temperature and atmosphere in the furnace by observing the flame color is indeed a common method used by the ancients. This is consistent with the method of identifying different substances with different characteristic flames and their corresponding temperatures in modern physics.

During the Western Han Dynasty, someone tried to make a temperature measuring device. Huainanzi? It is recorded in "Talking about Mountain Training" that the bottle is filled with water. When it freezes, it can indicate that the temperature is low. If it is soluble in water, it can also indicate that the temperature is rising. This observation can be regarded as the bud of the idea of thermometer.

The real invention of thermometer was in17th century. 1673, the Beijing Observatory made the air thermometer for the first time according to the introduction of the missionary Ferdinand ferdinand verbiest. But there are many people in China who make their own thermometers.

According to the collection of short stories edited by Juck Zhang, a writer in the early Qing Dynasty, Huang Lvzhuang invented a kind of "thermometer" in the early Qing Dynasty.

According to records: "This instrument can diagnose deficiency and excess, distinguish climate and prove the temperament of various drugs, and it is widely used, and there is another special book." It's just that the "special book" and the physical object of the hot and cold detector have been lost, so it's difficult for us to judge its specific principle and structure. Probably a gas thermometer or something. However, its structure and principle are not recorded. It may be a hair hygrometer, a balance hygrometer, or a barometer, because the relationship between air humidity and air pressure is very close. Huang Lv, an optician in Qing Dynasty, also made a "thermometer", which is said to be quite distinctive, but the original records are too brief to know its details.

Because the original records are too brief, we can't explain the specific situation of these folk inventions. But what is certain is that their activities show our people's enthusiasm for temperature measurement.