Last updated on April 16, 2014 at 14:08 EDT

Latest Watt balance Stories

2012-02-20 20:26:16

New research, published by the National Physical Laboratory (NPL), takes a significant step towards changing the international definition of the kilogram — which is currently based on a lump of platinum-iridium kept in Paris. NPL has produced technology capable of accurate measurements of Planck's constant, the final piece of the puzzle in moving from a physical object to a kilogram based on fundamental constants of nature. The techniques are described in a paper published in Metrologia...

2011-01-24 09:35:00

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. That prototype, which is a cylinder of platinum-iridium housed at the International Bureau of Measurements (BIPM) in France, has gotten approximately 50 micrograms (0.0000017 ounces) smaller over the past 100 or so...

2010-10-27 12:37:27

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. The new SI, which would be based on seven constants of nature, would enable researchers around the world to...

2008-02-28 18:53:08

Change should have little impact on nuclear weapons complexThe kilogram is losing weight and many international scientists, including some at Sandia National Laboratories, agree that it's time to redefine it.Scientists are hoping to redefine the kilogram by basing it on standards of universal constants rather than on an artifact standard.The International Prototype Kilogram (IPK) or "Le Grand K," made in the 1880s, is a bar of platinum-iridium alloy kept in a vault near Paris."The idea is to...