Redefining the Kilogram, the Kelvin, the Ampere and the Mole: Why you should care even though you won't notice
Talk by: Michael de Podesta (NPL)
Progress in science and engineering is often linked to progress in metrology. If we cannot measure something then we cannot begin to understand it (science) or improve it (engineering). And better measurement leads to better understanding and control.
Measurement is the quantitative comparison of an unknown quantity with a standard. In the International System of Units - the 'SI' - there are seven standard quantities called the 'base units': the second, metre, kilogram, ampere, kelvin, candela and mole. The perfection with which these definitions can be made real, represents a fundamental limit to achievable measurement uncertainty.
Image: © NPL