Thursday , February 25 2021

When 1 g is no longer the same. Are old scales available?

When 1 g is no longer the same. Old Scales Are Still Available? – BBC Thai

By Friday, November 16th, four kilowatts of mercury and kelvin will be converted into SI units. To achieve world-class precision measurements. And with sufficient resolution to support the development of modern science.

Metrological meeting is expected. Metrology, a unit of measurement with a scientific methodology from 57 countries, this new definition will be approved by the 26th IGC on Scales and Measures (CGPM) in France. This week And if nothing meets expectations. The new definition will come into force on May 20 next year.


Le Grand K, a standard metal shoe for 1 kg worldwide, has been used as a reference for over a hundred years.

What is the need for scientists to change the definition of these basic units? In particular, the kilograms that affect most people's daily lives are different. Subsequently suspicious Does the weights we use remain unchanged?

Goodbye "Le Grand K"

More than a century ago. Standard weight 1 kg worldwide. This is due to international kilograms. The international prototype of the Kilogram (IPK), a cubic-form, isotope-platinum alloy, is stored at the Bureau of the International Bureau of Statistics Bureau Vault in Paris (France).

Despite the fact that the high-rise glass is well-preserved, Big C should be removed to remove from time to time accumulative pollutants. The weight is the same. Officials will use suede (chamois) to impregnate alcohol and ether napkin. First of all, it is washed with steam coming from two distilled water.

But the problem is that. The purified filtering process of polluted substances is increasing. It makes you lose more weight than it would be. Thanks to the texture of the metal, it is washed slightly each time. Metrologists must reimburse the weight of the Le filter. Including metal blocks that are copied in other countries may not always be the same.

Weight loss filtered even with a little micrograms. But it creates confusion, which no less affects the modern science. Due to the tendency to study things at a lesser level, they are constantly limited, for example, in quantum and nanotechnology. More precise size and weight is required. For example, pharmaceutical and pharmaceutical research companies will need millions of dosage units and weighing unit reagents. Or even billions of parts of 1 gram soon.

Dr. Ian Robinson of the United Kingdom National Physical Laboratory (NPL) says: "Another important reason to re-define the weight of 1 kg. Refuse to refer to the Le filter. This is for safety. In the event of a severe fire, destroy the vault where the filter is located. it will become an embarrassing confusion that suddenly standard references have disappeared. This is a matter of international security. "

Dr. Stefan Schumacher from the United States National Institute of Standards and Technology (NIST). "In the future, if foreigners come to the world. And he spoke about science, especially about physics and metrics, if he knew that the world is still using metals, the whole universe will be laughing at us."

A new era with Kibble's balance.

Previously, metrology has attempted to improve the definition of 7 unit units in the international metric system. Link to the most basic scientific justification. Previously, the definition of the second meter and the candles was changed, which respectively referred to the distance and the degree of illumination. Referring to the natural processes of nature. For example, the speed of light in a vacuum. Only kilograms are still defined by referring to artificial objects.

a scientist at work at the kibbal balance

Kibble Libra Invented and created since 1975 by English physicist Dr. Bryan Kibble who carried out a metrological study.

The latest international metrology has agreed to review the 1 kg definition of weight. Referring to the abstract numbering as "Planck's constant"

These constants are the numbers used to describe the energetic phenomena that occur at particle levels. Like quantum physics. Planck's constant represents the relation between energy in a particle and an electromagnetic wave photon. Frequency of such waves during radiation. This is 6,626 x 10-34 joules.

Planar constant relative to the new standard 1 kg weight. Due to the use of energy or electromagnetic force in comparison with object weighing in detail. It is assumed that the electromagnetic force acting on the object is equal to the gravitational force acting on the mass. The weight of the object itself. Planck's constant is equal to the energy of one object, until it is 1 kilogram per square meter per second.

The principle of electromagnetic energy is a comparative weighing object, or the "Kibble weights" have been invented and developed since 1975, before the British physicist Dr. Bryan Kibble began. Metrology research. This scale acts as a traditional scales. But abstract weight as electromagnetic energy. Instead of metal or other material.

Many people may wonder. When the kilogram definition is changed, Planck's constant is a reference. Will it affect the everyday life of ordinary people other than scholars? Will we need to replace existing scales with high-tech devices, such as Kibble scales?

Many metrologists say that. Of course, changes in the definition of kilograms will not affect us, as this is only among scientists. Only in the future, according to the new definition, a standard 1 kg weight scale could be produced. Usually it is used for calibration.

Will be more precisely measured in kilograms of the future.

Science photo library
Will be more precisely measured in kilograms of the future.

Reassessment of basic measurements in SI systems

The development of international units in France began in the middle of the 18th century, and later the development of the metric system was eventually renewed in the form of SI. It also develops continuously. Kilograms Base units are all units of measurement in international units. The definition is based on the following constants:

– The second measurement in seconds, which is equal to the time when the cesium atoms break down. Or vibration 9 192 631 770 times

– Meter in meters (meter) indicates a speed of 1 meter, the distance from which the light passes in a vacuum in 1 / 299,792,458 seconds.

Kelvin has one Kelvin, which is equal to the particle and temperature ratio. Based on Boltzmann's constant.

– the unit of measurement is the amperage (ampere) amperes equal to the electron charge. This is a negative payment.

1 mole mole is equal to the Avogadro constant of 12 g 12-carbon.

– 1 Candela is the single-wavelength efficiency of a single wavelength ray.

Source link