The Institute of Physics has erected blue plaques in various locations around the United Kingdom and Ireland in order to celebrate physicists who lived or worked in the locality.

Ernest Thomas Sinton Walton (1903 - 1995)

Location: Physics Department, Trinity College, Dublin
Unveiled: 9 September 1997 by Mary Robinson, President of Ireland, in the presence of Dr Brian Manley, President of the IOP, Professor John McGilp, Head of Physics, and Dr Tom Mitchell, Provost of Trinity College.

Walton undertook undergraduate and postgraduate studies at Trinity College, Dublin, before going up to Cambridge University. Whilst there, he worked with John Cockcroft on the first ever nuclear accelerator experiment, using protons accelerated to 700 keV. They were jointly awarded the 1951 Nobel prize for physics for this work on transmutation of atomic nuclei by artificially accelerated atomic particles. Two years after this collaboration, in 1934, he returned to Trinity college, and remained there until his retirement in 1974. Walton lived until the age of 91, having presented his Nobel citation and medal to his college on his 90th birthday. One of the reasons that Mary Robinson agreed to unveil this plaque at the very end of her term of office was that he was one of her sponsors when she stood for election to the Irish Senate.

Walton was Chair of the Irish Branch from 1966 to 1968.

Biography: Ernest Walton: the Irish Scientist, by Vincent McBrierty

Nicholas Joseph Callan (1799 - 1864)

Location: St Patrick's College, Maynooth, Co. Kildare (Stoyte House, left corridor)
Unveiled: 17 April 1998

Nicholas Callan was born on December 22, 1799, at Darver, between Drogheda and Dundalk. He entered St Patrick's College, Maynooth, in 1816, and was to remain there for almost all of the rest of his life. In his third year at Maynooth, Callan studied natural and experimental philosophy under Dr Cornelius Denvir, who introduced the experimental method into his teaching, and had an interest in electricity and magnetism. After ordination as priest in 1823, Callan went to Rome, where he studied at the Sapienza University, obtaining a doctorate in divinity in 1826. While in Rome he became acquainted with the work of Luigi Galvani (1737-1798) and Alessandro Volta (1745-1827). On the resignation of Dr Denvir, Callan was appointed to the chair of natural philosophy in Maynooth in 1826, and he remained in that post until his death in 1864.

Callan's major claim to fame is as the inventor of the induction coil. Following earlier experiments, he discovered in 1836 that, when a current sent by battery through a primary coil was interrupted, a high voltage current was produced in an unconnected secondary coil. Callan sent a replica of his coil to William Sturgeon (1783-1850) in London in 1837, and it was exhibited to members of the Electrical Society there to their great amazement.

Scientific apparatus and literature on Callan: National Science Museum, Maynooth

John Stewart Bell (1928 - 1990)

Location: Pure and Applied Physics Department (on the quadrangle side of the Old Physics Building), Queen's University, Belfast.
Unveiled: 7 May 2002 by his widow Mary Bell, in the presence of the Lord Mayor of Belfast and many representatives from Queen's University and the Institute of Physics.

John Bell played a key role in our understanding of the nonlocality principle of Quantum Theory summarized by Bell's theorem in 1964. Bell's work probed most deeply the philosophical foundations of the nature of matter and he is universally acknowledged as one of the greatest physicists of all time. His ideas led directly to quantum information theory and quantum computation, which are among the most exciting research topics for the new century. Bell became a Fellow of the Royal Society in 1972, and between 1987 and 1989 he was awarded the Hughes Medal of the Royal Society, the Dirac Medal of the Institute of Physics and the Heineman Prize of the American Physical Society. In 1988 he received honorary degrees from both Queen's University, Belfast and Trinity College, Dublin.

Collected papers:J S Bell: Speakable and Unspeakable in Quantum Mechanics, Cambridge University Press 1993.
On-line biography: http://physicsworld.com/cws/article/print/1332