'How do you really know what the temperature is?' Lecture

Everybody measures temperature – and everyone sort of knows what temperature is. In this talk I will first outline how we make the connection in practice between the energy associated with the microscopic jiggling of atoms and molecules and the temperature scale we all use (Celsius). Then I will describe the rationale for the forthcoming redefinition of the unit of temperature, and why, although you won’t notice, it is still a good idea! Finally, I will explain why every temperature you ever measured was a little bit wrong – and how we can put it right!

Dr Michael de Podesta, National Physical Laboratory