Chinese scales

When it comes to "measurement", many people often blurt out "calibration scales", which is obviously incorrect, but it also expresses the fact that people are too familiar with scales. Originally, buying rice and noodles, weighing meat and vegetables... inside and out, where can we live without a scale? A scale is a measuring instrument used for weight measurement. Weight measurement is one of the measurement activities that humans have been engaged in since they learned to use labor tools to transform the environment, with the aim of conducting the ancient exchange of goods at that time. Before the existence of specialized measuring tools, ancient people relied on their limbs and sensory organs for measurement, and the famous phrase 'holding hands to lift' was a vivid portrayal of weight measurement at that time. In the bronze inscriptions of the Western Zhou Dynasty (approximately 11th century BC to 771 BC), there are records such as "Jin Shi" and "Jin Shi Yun". "Jin" refers to copper, and "" and "Yun" are units of weight, indicating that there were already methods for calculating weight at that time. The Book of Han's "Food and Goods Chronicles" records that "gold measures one inch and weighs one pound", while the "Book of Later Han's" Etiquette Chronicles "records that" one liter of water weighs thirteen taels in winter ". This indicates that by 200 BC, China had already been able to use metal and water with fixed temperature and capacity as a unit of weight. When it was found that the measurement units determined by the human body were difficult to accurately reproduce and maintain stability, in order to adapt to the constantly expanding production scale and the growing needs of commodity exchange, ancient people began to seek the production of physical standard instruments. The Xinmang Copper Jialiang is an outstanding work in this exploration process. It was made by Wang Mang during his reign as emperor in the late Western Han Dynasty (9-23 AD), and consists of five capacity units: the top is a hu, the bottom is a dou, the left ear is a sheng, the top of the right ear is a he, and the bottom is a lun. One vessel can measure five quantities, which can be used as both a capacity standard and a measurement standard. It can also be derived as a scale standard, unifying the degree, measurement, and balance into one vessel. Like the standard measuring vessel - Shang Yang Copper Square Sheng issued by Shang Yang in Qin in 344 BC, the capacity of the vessel is determined by the method of measuring the volume according to the degree. The scale also emerged during this exploration process. Examining the development history of weighing instruments both domestically and internationally, it is almost always the case that the balance first existed and then gradually evolved into a scale. The Chinese balance was born during the Spring and Autumn Period and the Warring States Period. With the passage of time, the handle in the middle of the balance gradually moved from the middle to one end, and the weight and two numbers were engraved on the balance pole, thus forming the prototype of the suspension pole balance. It was originally believed that the appearance of scales in China dates back to the Three Kingdoms period. Later, a wooden pole scale dating back more than 2000 years was discovered in a Western Han tomb in Meixian, Shaanxi. Experts identified it as the oldest known physical wooden pole scale in China to date. Some unearthed iron scales from the Northern Wei and Northern Qi dynasties have confirmed that pole scales from the Wei, Jin, and Southern and Northern Dynasties periods have been widely used. Nowadays, the scales in our country have evolved from a single pole scale in the past to a vast "scale family" with many different types. In terms of its balance principle, scales can be roughly divided into the following types:

1. Scale based on the principle of leverage. Common types include wooden pole scales, cutting scales, dial scales, platform scales, floor scales, track scales, and various equal arm and unequal arm scales. When weighing an object on such a scale, the sum of the external forces acting on the lever must be zero. This type of scale is widely used in commercial, industrial, and other economic activities.

2. A scale that utilizes the principle of elastic deformation. The principle of its operation is that the gravity of an object is balanced by the elastic force generated by the deformation of the spring under the pressure. Common types include torsion scales, spring scales, and large suspension scales.

3. Scale based on hydraulic principles. The pressure of the object is balanced by the pressure of the working fluid, and this type of scale is called a hydraulic scale, which generally weighs over 1 ton.

4. A scale that applies the principle of quartz oscillation. Adding an unknown plate to a resonant quartz crystal will change the natural frequency of the quartz plate due to the increase in oscillation mass, as the natural frequency of the quartz oscillator can be accurately measured (10-11), thus obtaining a very precise method for measuring thin film materials.

5. Scale based on electromagnetic principles. The torque of mechanical force on such scales is balanced by the torque of electromagnetic force or electrical force, including ampere scales, volt scales, electromagnetic scales, etc.

6. A scale that utilizes the principle of magnetic suspension (known as a magnetic suspension scale). The basic principle is that a small steel ball made of ferromagnetic material is freely suspended in a solenoid, balanced by the magnetic field generated by the solenoid. The vertical position of the ball is automatically adjusted and maintained by the current passing through the solenoid. By measuring the current on the coil through changes in the suspension mass, the mass can be measured with an accuracy of 10-5 and a minimum mass of 10-11g.

7. Electronic scale (electronic balance). Adding an electronic regulator to a regular balance becomes an electronic balance. It uses a displacement sensor to convert the displacement caused by the balance's deflection into an electrical signal, which is input into an amplifier and then fed back to the torque converter to restore the balance to its zero position. Due to the electronic feedback circuit changing the balance parameters, the reaction speed is fast, so the balance reaches equilibrium in a very short time. Its advantage is that it eliminates errors caused by excessive tilt angle of the balance, with a high measurement accuracy of up to 10-5, fast reading, and high efficiency. The principle of an electronic scale is the same as that of an electronic balance. Large scale electronic scales often use resistance strain gauges as displacement sensors, while small scale scales (scales) use inductive, photoelectric, capacitive and other displacement sensors. In the world of complex and spectacular scales, the most closely related to people's daily lives is probably the market commercial scale, which is also a more common type for most people. Based on the current situation of measuring instruments used in the market, this type of scale generally includes pole scales, desktop spring dial scales, cutting scales, and electronic pricing scales. Maintaining and ensuring the same value ratio between supply and demand in commodity trade is probably the original intention of human invention of scales. However, due to the lack of moral and legal concepts among some people, the variety of fraudulent practices on scales today is simply astonishing. In addition to national supervision and management, users and consumers should also establish strong self-protection mechanisms.