Latest SI base units Stories
To support the fair sale of gaseous hydrogen as a vehicle fuel, researchers at the National Institute of Standards and Technology (NIST) have developed a prototype field test standard to test the accuracy of hydrogen fuel dispensers.
The U.S. Department of Commerce's National Institute of Standards and Technology (NIST) has officially launched a new atomic clock, called NIST-F2, to serve as a new U.S. civilian time and frequency standard, along with the current NIST-F1 standard.
In a groundbreaking new study, physicists from the University of California, Berkeley have used atomic matter to measure time.
Scientists from University of Newcastle say that the platinum-based kilogram standard has been putting on weight over the years, adding tens of micrograms of hydrocarbon "pollution" every year.
Groundbreaking research by the National Physical Laboratory's (NPL) Quantum Detection Group and an international team of collaborators is underpinning the biggest change in the Système Internationale d'unités (SI Units) since the system began 50 years ago.
The electromagnetic force has gotten a little stronger, gravity a little weaker, and the size of the smallest "quantum" of energy is now known a little better.
Avogadro constant determined with enriched silicon-28.
Scientists are close to establishing a non-physical definition of the kilogram--the last remaining base unit in the International System of Units (SI) still defined by an existing object--after it was revealed that the prototype used to establish the measurement is shrinking.
Taking the first steps of what would be a major historical advance in the science of measurement, the National Institute of Standards and Technology (NIST) is participating in a worldwide effort to recommend major revisions to the International System of Units (SI), the modern metric system that is the basis of global measurements in commerce, science and other aspects of everyday life.
Physicists at the National Institute of Standards and Technology (NIST) have built an enhanced version of an experimental atomic clock based on a single aluminum atom that is now the world's most precise clock, more than twice as precise as the previous pacesetter based on a mercury atom.