SCIENCE IN THE NEWS DAILY
The Kilogram, Reinvented
from IEEE Spectrum
Once a year, three officials bearing three separate keys meet at the bottom of a stairwell at the International Bureau of Weights and Measures, in Sèvres, France. There they unlock a vault to check that a plum-size cylinder of platinum iridium alloy is exactly where it should be. Then they close the vault and leave the cylinder to sit alone, under three concentric bell jars, as it has for most of the past 125 years.
This lonely cylinder is the International Prototype of the Kilogram, known colloquially as Le Grand K, and it is the last remaining physical object to define a unit of measure. It's a quaint throwback to a time when people compared the ocean's depth to the span of a man's outstretched arms and the second to a tiny fraction of a year.
Now we fix our rulers to the speed of light and our clocks to a spectral property of cesium. By thus linking measurement to fundamental and unchanging phenomena, scientists have paved the way for GPS satellites, gravity-wave detectors, and many other precision technologies that simply wouldn't have been possible before.
Connect With Us:
PODCAST & VIDEO: 3D Printing Replacement Body Parts
Regenerative medicine, a fledgling field with the aim of regrowing parts from a person’s own cells, is being amplified with 3D-printing technology, which can now use organic materials to create scaffolds that cells need to grow into their final forms. Richard Wysk, a professor of industrial and systems engineering at North Carolina State University, discusses the latest successes with this research, and the timeline for creating more complicated structures.
To view all multimedia content, click "Latest Multimedia."
Receive notification when new content is posted from the entire website, or choose from the customized feeds available.