‘On Metrology’ by Terry Quinn (postponed from Jan 2022)
April 12 @ 6:00 pm - 8:00 pm
This event is both an in-person and on-line event. To reserve a spot for either option, please visit the lecture’s Eventbrite page.
Terry Quinn graduated in physics just one year before the great revolution in metrology began with the redefinition of the Metre in terms of the wavelength of light. From antiquity, practical dimensional measurement standards had all been based upon material artifacts and measurement of time on the rotation of the Earth. All of that changed in 2018 when the base units of the SI were redefined in terms of fixed values of a set of fundamental and atomic constants. In this lecture, Quinn will explain how practical measurement standards can be obtained from such definitions.
The above image shows “Toise du Perou” (the official unit of length in France just before the metric system). This is one of two Toises that were used to decide between two theories for the shape of the Earth – one by Newton in which the earth was flattened at the Poles and one supported in France by Cassini, who maintained that it is pointed like an upright rugby football. One Toise was taken to Lapland (the Toise du Nord) and one (this one) to Perou where the length on the ground of one degree of latitude was measured. The expeditions lasted some years in the 1740s and, of course, the results supported Newton’s theory. (Photo TJQ at the Paris Observatory 2017).
About The Lecturer
Terry Quinn graduated in Physics from Southampton University in 1959, moving to Oxford for his D. Phil in what was then the Metallurgy Department. The thesis supervisor was Professor William Hume-Rothery FRS.
In 1962, Quinn joined the National Physical Laboratory in Teddington where he worked on high-temperature measurement and standards. In 1967/68, Quinn spent a year at the then National Bureau of Standards in Washington, moving to the BIPM, Paris in 1977 as Deputy Director, becoming Director in 1988. He was Lady Margaret Distinguished Visiting Fellow at the Cavendish Laboratory, Cambridge in 1984/84 and retired from the BIPM in 2003. Quinn was elected a Fellow of the Royal Society in 2002.