Progress in science and engineering is often linked to progress in metrology – the science of measurement. If we cannot measure something then we cannot begin to understand it (science) or improve it (engineering).
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. In order to remove these limits, from May 2019 there will be subtle but profound changes in the definitions of four of these base units – the kilogram, ampere, kelvin and mole. In this talk Michael de Podesta will explain the rationale for the forthcoming changes and why, even though you are unlikely to personally notice any changes, you should be happy about them.
Speaker: Dr Michael De Podesta from NPL