Graphene and Quantum Hall Effect Could Help Redefine Metrics 92
eldavojohn writes "The National Physical Laboratory has published research in Nature that could lead to redefining two of our most commonly used metrics. There's been a lot of trouble stemming from defining an exact Kilogram as some lump of platinum-iridium sitting in a glass case somewhere, so the proposal was put forth to study the quantum hall effect with different materials. Enter the Nobel prize winning, super strong, silicon usurping graphene. NPL now says you can add quantum resistance metrology to the list of graphene's many conquests as they say the quantum hall effect in graphene is 'very robust and easy to measure.' With this at their disposal, the Kilogram may be redefined in terms of h, the Planck constant, and the Ampere may be redefined in terms of e, the electron charge (alias Elementary charge or the charge of a proton). You can find the full paper here."
Re:I guess I always assumed... (Score:4, Informative)
The definition of a unit must be physically instantiable. That is, you have to be able to use the definition to build a device or artifact that can be used to calibrate a meter for said unit. Otherwise, the unit is useless.
This means that some units still have cumbersome and strange definitions, as we do not have the technology to use the obvious definitions to calibrate measurement devices.
Re:So Metric will change..again. (Score:3, Informative)
1963 when the UK parliament adopted the international definition (from 1959) of the pound as 0.45359237 kilogrammes. Ironically for you, it will change again if the definition of the kilogramme changes as per the article.
3 orders of magnitude better than the lump (Score:5, Informative)
I, for one, welcome our incredibly accurate overlords.