In recent years, there has been a lot of discussion about Zhang Heng's ground motion instrument. In the human-taught edition of textbooks before 2010, Zhang Heng's ground motion instrument is regarded as a model of the great scientific and technological inventions of ancient China, and has entered the textbook and become the collective memory of generations of Chinese.
In the seventh grade volume of the unified junior high school history textbook put into use in the autumn of 2017, the content about Zhang Heng and the weather wind and ground motion instrument was deleted. The ground motion model that has been printed on textbooks and has influenced generations of Chinese has begun to fade out of the vision of contemporary teenagers.
Fu Chengyi, an academician of the Chinese Academy of Sciences, pointed out even more: "The hanging pieces of meat under the beam are stronger than your model." Why is that? This is because the textbook Zhang Heng ground motion instrument is a replica, not the real Zhang Heng ground motion instrument.
<h1 class="pgc-h-arrow-right" data-track="6" > the origin of the ZhangHeng ground motion instrument in textbooks</h1>
During the Eastern Han Dynasty, earthquakes were relatively frequent, and the studious Zhang Heng wanted to invent an instrument to grasp the dynamics of earthquakes across the country. After a long period of research, he finally invented the weather wind and ground motion instrument in 132 AD. Eight dragons correspond to eight directions, each with a copper ball in its mouth, and in which direction an earthquake occurs, the corresponding copper ball will fall into the mouth of the toad below.
This was the world's first ground motion instrument. More than a thousand years before the history of earthquakes recorded by Western countries with instruments. However, this "ground motion instrument" disappeared in the last years of the Western Jin Dynasty.
Mr. Wang Zhenduo, China History Museum. Based on the description of the Later Han Dynasty, he deduced the basic principle of the ground motion instrument: the upright pole principle.
Later, Mr. Wang Zhenduo, based on the British Milne's inference of the working principle of the overhang pendulum, drew a ground motion instrument restoration figure in 1936, and in 1951 made an exhibition model based on the inference of the Japanese Hagiwara And Imamura Akihide on the working principle of the upright pole, which was later displayed in the China Museum of History (now the National Museum of China).
After the traditional model made by Wang Zhenduo came out, it was introduced by the People's Pictorial in 1952 and selected by the Chinese special stamp in 1953. It has also been used as an important carrier of Cultural Exchanges between China and foreign countries for many times, and even traveled across the ocean in the form of a national ceremony, and exhibited side by side with the rocks brought back from the moon by the United States at the headquarters of the United Nations World Intellectual Property Organization, enjoying the same honor.
Therefore, the "Zhang Heng Ground Motion Instrument" restored by Wang Zhenduo was compiled into the national primary and secondary school textbooks, and even the China Earthquake Administration used this restoration model to mark it for decades, and it was not taken down until a few years ago.
This model has made indispensable contributions to promoting national culture, publicizing ancient Chinese scientific and technological achievements and popularizing science. As a result, many people think that this is the original ground motion instrument.
<h1 class="pgc-h-arrow-right" data-track="20" > the textbook Zhang Heng ground motion instrument is actually "fake". </h1>
But in fact, Wang Zhenduo's restored "Zhang Heng Ground Motion Instrument", because the internal structure of the model lacks rationality, so the copper pills in the dragon's mouth cannot be spit down, and the earthquake cannot be detected at all.
Wang Zhenduo's reference to the upright bar principle is based on the unstable balance of the object, and the inductive components all exhibit dumping, falling and collapsing. The alarm cannot automatically distinguish the nature of the vibration source, the sensitivity is not high, and the reaction is random, unstable and non-repeatable. Once the device is alarmed, it is impossible to determine whether it is caused by a car or an earthquake. To put it simply, this principle is equivalent to the wine bottle standing upside down on the ground, and if the bottle is poured, it means that the earthquake has come.
E And strict seismological calculations, laboratory tests and seismic tests at home and abroad have long proved that this upright rod principle can only be used for low-sensitivity alarms, and does not have the rationality and feasibility of building a seismometer, which was eliminated as early as the 18th century.
Countless ground motion instruments made across the country modeling this model, as small as the palm of the hand, as large as millions of yuan, and even consume more than 10 tons of copper, as high as 2.96m, do not have the basic function of the seismic detector.
What is even more embarrassing is that when this "Zhang Heng Ground Motion Instrument" visited Nara, Japan in 1988, the Chinese commentator held a wooden stick and stabbed it when explaining the working conditions of the Ground Motion Instrument to the Japanese audience, and the copper pill in the dragon's mouth would fall into the mouth of the toad below.
Since 1969, the academic circles of China, Japan, the United States, the Netherlands and Austria have published a series of serious critical articles, and foreign popular science articles have also questioned its principles or made other interpretations.
Academician Bolt, an American seismologist, pointed out after looking at the traditional model photos:
The most popular geokinetic model in China currently has a vague working principle, the model is simple and rough, mechanical friction greatly reduces the sensitivity, the response to earthquakes is lower than the sensitivity of residents, its role should be questioned, and the use of copper pellets to determine the epicenter is also uncertain.
Unfortunately, these persistent, pertinent, and professional serious criticisms and negative opinions have not attracted much attention for decades, and the domestic media and teaching content have remained the same, and there has not been a rigorous scientific test and seismological test for decades.
<h1 class="pgc-h-arrow-right" Data-track="6" what does > real tension geokinetic instrument look like? </h1>
The real Zhang Heng ground motion instrument has long been lost in the Western Jin Dynasty, according to the research of scientists, the core principle of the ground motion instrument should be the suspension pendulum theory. Rather than the "upright" theory.
Liquid free surfaces and overhangs are two of the most basic natural seismic structures. Since various non-seismic interference waves (driving and moving, exploding) are mainly vertical movements, consistent with the gravitational direction that maintains the level of liquid and the stability of the overhang pendulum, it is not or extremely difficult to make them leave the original equilibrium position. Seismic waves, on the other hand, move in a horizontal direction and have a strong excitation effect on them. Therefore, once such a device appears to swing and shake laterally, it will show the physical properties that can automatically distinguish between earthquakes and non-earthquakes on a macroscopic level, that is, "verify the earthquake", so it is named a seismometer. The principle of Zhang Heng ground motion instrument should use the suspension swing theory.
The hanging piece of meat under the beam is the most basic natural seismic structure, which is why Academician Fu Chengyi pointed out: "The hanging piece of meat under the beam is stronger than your model".
At present, the most recognized by the archaeological community and the scientific and technological community is the Zhang Heng ground motion instrument restored by Feng Rui, a professor at the Graduate School of the Chinese Academy of Sciences, who calculated the specific height, shaking period and frequency of the pillar, and determined the form and structure of the core components. Then, according to the limit of eight feet (1.85 meters) in diameter, he attached the toad placed around the Wang's ground motion instrument and attached it to the deity and connected with it.
Feng Rui's research group also transferred the waveform map of the Longxi earthquake, and through the calculation of the waveform map, simulated the fluctuation effect of the Longxi earthquake in 134 AD. After the fluctuation, the copper ball should fall in waves.
Feng Rui's restored Zhang Heng ground motion instrument only spit out pills when the transverse wave came, and other vibrations from the longitudinal wave could not make the ground motion instrument have any reaction. This means that similar doors, car crossings, and loud artillery fire will not interfere with the geokinetic instrument.
In the 7-day experiment that followed, the ground motion instrument did not make a single mistake. Therefore, Feng Rui's restored Zhang Heng ground motion instrument passed the appraisal of the acceptance committee composed of experts in seismology, archaeology, mechanical engineering and other related disciplines.
Since then, Feng Rui has wandered many times, hoping to correct this mistake in the textbook. Thanks to Feng Rui's efforts, Mr. Wang Zhenduo's restored ground motion instrument model was withdrawn from the textbook.
However, although Feng Rui's Zhang Heng ground motion instrument is scientific, the Zhang Heng ground motion instrument has been lost for more than 1700 years, and in the final analysis, this is only "our understanding of Zhang Heng in the current era". As for what the weather wind ground motion instrument of more than a thousand years is like, whether future generations will create a Zhang Heng ground motion instrument that is closer to the original appearance, it is still impossible to easily draw conclusions.