Define a Kilogram

Counterintuitive Narratives

The Definition of a Kilogram

• The Definition is about to Change
  • “If Le Grand K gets heavier or lighter — or absorbs atoms of something from the air — the definition of the kilogram literally changes. Scientists believe something like this has been happening, because Le Grand K seems to now weigh slightly less than its official copies.”
  • “The originators of the metric system based it on the globe itself, with the meter described as one 10-millionth of the distance from the North Pole to the equator. But, for a long time, the meter was literally a metal bar in France. As physics advanced, says Schlamminger, scientists were able to ditch the metal bar and define the meter in terms of the distance that light can travel through a vacuum in about one 300-millionth of a second.”

The U.S. National Institute of Standards and Technology in Maryland has its own copy of Le Grand K — a platinum-iridium kilogram known as K92.  

The New Kilogram is based on Planck’s constant

Now, after researchers spent years creating an elaborate new kind of weighing machine called a Kibble balance, it’s finally the kilogram’s turn. In the future, to see whether a hunk of metal really weighs 1 kilogram, it won’t have to get flown to France and compared with Le Grand K. It can be evaluated in this type of instrument, using Planck’s constant.”

The Consequence of
Perfect Attendance Awards

• Perfect Attendance Awards
• The Study
  • As states and districts struggle to prevent chronic absenteeism, rewarding students for
    attendance has been seen as low-hanging fruit—California even requires it by law.
    In a forthcoming study previewed at the annual Society for Research on Educational
    Effectiveness meeting in Washington last week, researchers found that older students who received recognition certificates were actually less likely to continue going to school every day than students who received nothing at all.