David Acheson

David Acheson is a British applied mathematician, best known for his 'upside-down pendulums' theorem and for his best-selling book

He was born in 1946 and educated at Highgate School, in North London. In 1967 he took a 1st class Honours degree in mathematics and physics at King's College, London, winning the Alan Flower Memorial Prize. He obtained a Ph.D in mathematics at the University of East Anglia in 1971, and then held a NERC Research Fellowship at the Meteorological Office, working with Raymond Hide. He took up a Junior Lecturership at Oxford in 1973, and a research fellowship at St Catherine's College in 1976. In 1977 he was appointed a Fellow in Mathematics at Jesus College, Oxford.

His early research was on geophysical and astrophysical fluid dynamics, beginning with the discovery in 1972 of a magnetic 'field gradient' instability in rotating fluids. Later, in 1976, he discovered the first examples of wave over-reflection (i.e. reflection coefficient greater than unity) in a stable system.

In 1978 he published a wide-ranging paper on magnetic fields and differential rotation in stars, with new results on magnetic buoyancy, the Tayler instability, Goldreich-Schubert instability, and, especially, what is now called the 'magnetorotational' instability.

His first book, *Elementary Fluid Dynamics*, was published in 1990, and is now widely used around the world as an
introduction to undergraduate fluid mechanics.

In 1992 he discovered the 'upside-down pendulums theorem' (which is very loosely connected with the Indian Rope Trick), and the theorem
and associated experiment featured on BBC TV's * Tomorrow's World * in October 1995. This led to a second book, *From
Calculus to Chaos* (1997), which was neither a 'popular maths' book nor a textbook, but something in between.

His first 'popular' maths book, *1089 and All That*, was published in 2002, and has now been translated into 11 languages.

In 2004 he became Oxford University's first winner of a National Teaching Fellowship, and was elected Emeritus Fellow of Jesus College, Oxford in 2008.

He served as President of the Mathematical Association for 2010-11.

In 2013, David Acheson was awarded an Honorary D.Sc by the University of East Anglia for his outstanding work in the popularisation of mathematics.