The Kilogram Has Gained Weight
Ron Czapala
Posts: 2,418
Full Article:
http://news.yahoo.com/kilogram-gained-weight-005533827.html
The kilogram may need to go on a diet. The international standard, a cylinder-shaped hunk of metal that defines the fundamental unit of mass, has gained tens of micrograms of mass from surface contamination, according to a new study.
As a result, each country that has one of these standard masses has a slightly different definition of the kilogram, which could throw off science experiments that require very precise weight measurements or international trade in highly restricted items that are restricted by weight, such as radioactive materials.
But ozone and ultraviolet light could be used to clean the kilograms without damaging them, the research suggests.
The cleaning technique, described in the January issue of the journal Metrologia, may eventually be widely adopted as a way to keep the fundamental unit of mass more consistent.
In addition, since it uses "equipment that one could come by without too much investment of time and money," it is a practical technique that could be widely adopted,
said Richard Davis, a metrologist who consults for the International Bureau of Weights and Measures in Paris, who was not involved in the study.
Common standard
The kilogram was first adopted as an international standard at the Convention of the Meter in 1875.At that time, scientists were frustrated that there was no consistent, standard way to measure mass with high precision.
http://news.yahoo.com/kilogram-gained-weight-005533827.html
The kilogram may need to go on a diet. The international standard, a cylinder-shaped hunk of metal that defines the fundamental unit of mass, has gained tens of micrograms of mass from surface contamination, according to a new study.
As a result, each country that has one of these standard masses has a slightly different definition of the kilogram, which could throw off science experiments that require very precise weight measurements or international trade in highly restricted items that are restricted by weight, such as radioactive materials.
But ozone and ultraviolet light could be used to clean the kilograms without damaging them, the research suggests.
The cleaning technique, described in the January issue of the journal Metrologia, may eventually be widely adopted as a way to keep the fundamental unit of mass more consistent.
In addition, since it uses "equipment that one could come by without too much investment of time and money," it is a practical technique that could be widely adopted,
said Richard Davis, a metrologist who consults for the International Bureau of Weights and Measures in Paris, who was not involved in the study.
Common standard
The kilogram was first adopted as an international standard at the Convention of the Meter in 1875.At that time, scientists were frustrated that there was no consistent, standard way to measure mass with high precision.
Comments
I gather they compare it with other "standard" kilogram copies and note they are different. But which is the correct one? Or is the gravity in Paris getting weaker?
Must be a more up to date measure - something based on natural units maybe http://en.wikipedia.org/wiki/Natural_units