SoylentNews is people
SoylentNews
Technische Universität Ilmenau and the Physikalisch-Technische Bundesanstalt (the National Metrology Institute of Germany) are developing a balance which is required for measuring the redefined kilogram that will be introduced in 2018. Called the Planck balance, this highly precise electronic weighing balance is not based on weights, but refers to the fundamental physical constant called Planck's constant. The balance will be used worldwide for calibrating other scales or balances so that they correspond to the system with this new method. The new balance will also be used in industry for measuring weights.
In many sectors, there is a significant demand for highly precise balances, including pharmaceutical companies for precise dosing of medical products, in official metrology service labs for calibrating scales for food, and in police departments, for the proof of toxic substances and in ballistics.
The original kilogram, a 4 cm cylinder made from platinum and iridium and stored under three glass domes in a safe near Paris since 1889, is becoming lighter. Over 100 years, it has lost 50 millionths of a gram. As all scales worldwide refer indirectly to this unique kilogram, they all weigh incorrectly, even if by minimal and negligible amounts. Although the original kilogram is becoming lighter, structurally identical copies of the prototype are used worldwide – which means that these copies are slowly becoming heavier relative to the prototype. Therefore, a new standard is required that does not change and cannot be damaged or lost.
In 2018, the new kilogram will be adopted at the 26th General Conference on Weights and Measures. It is not defined by an object or a physical mass, but by Planck's constant. The highly precise, continuously measuring Planck balance, developed by the German university Technische Universität Ilmenau, operates on the principle of electromagnetic force compensation. Simply put, a weight on one side is to be balanced by electrical force on the other. This electrical force is inextricably linked with the Planck's constant and can be directly referred to the new kilogram definition. As this balance is the first self-calibrating instrument of its kind, masses determined as reference or standard masses for calibrating scales and balances are no longer required. Another advantage of the Planck balance is its wide measuring range, from milligrams to one kilogram. At the end of the year, the first prototype of the balance will be available and ready for use.
At last, a balanced article.
(Score: 3, Insightful) by stormwyrm on Wednesday June 21 2017, @06:36AM (6 children)
I can't seem to find any references to the Planck balance except in the many clones of the linked article, which all seem to be based on a press release from Technische Universität Ilmenau, which invented the thing. The fact that the term doesn't seem to be mentioned elsewhere (try Googling "Planck balance" Ilmenau [google.com]) makes me think that any scholarly articles describing its operation might be in German only. If it's seriously being considered as the basis for the SI definition of the kilogram, there ought to be a lot of peer-reviewed papers describing it.
Numquam ponenda est pluralitas sine necessitate.
(Score: 0) by Anonymous Coward on Wednesday June 21 2017, @09:36AM (4 children)
If you remove the quotes, then you'll find plenty links to a Watt balance [wikipedia.org] which seems to be the proper name of that balance used to redefine the Kilogram. The authors of the article probably got confused because the new kilogram definition is based on Planck's constant.
(Score: 2) by stormwyrm on Wednesday June 21 2017, @10:06AM (3 children)
Numquam ponenda est pluralitas sine necessitate.
(Score: 2) by opinionated_science on Wednesday June 21 2017, @10:32AM
I would imagine (not RTFA!) the principles are now implemented in solid-state. There has been astonishing advancement in micro-electronic, micro-mechanical and micro-magnetic materials... (look at your computer and phone!).
As a side bar, and before I have my coffee....if this becomes standard the measuring devices might become very cheap - who knows what a really accurate mass-balance could be used for?
(Score: 0) by Anonymous Coward on Wednesday June 21 2017, @12:27PM (1 child)
I think the Watt balance has been renamed Planck balance to keep the Germans happy. They have historically supported replacing the kg artifact with a Silicon sphere that has a known number of atoms.
(Score: 2) by stormwyrm on Wednesday June 21 2017, @11:15PM
Numquam ponenda est pluralitas sine necessitate.
(Score: 1, Interesting) by Anonymous Coward on Wednesday June 21 2017, @11:00AM
Briefly, Planck-Waage / Planck-balance is Ilmenaus marketing name for their superconducting Watt- or Kibble-Balance.
The curent measurement is done by Josephson-junction. Thats where the Planck quantum comes in.