John Stewart Orr

John Stewart Orr FRSE FIP (d. 2001) was a 20th-century Scottish medical physicist and researcher. He was the creator of Orr's Spherule, a scientific teaching tool.

Life He was born at 34 Gray Street in Glasgow on 10 August 1930, the second son of Neil Orr, a lawyer. The family lived most of their life in Milngavie.

He was educated at the Atholl Preparatory School in Milngavie and Glasgow High School then studied Physics at Glasgow University graduating BSc. Although too young to serve in the war he served two years National Service in the late 1940s. For a while he worked with Barr and Stroud in Glasgow making specialist scientific instruments. Here he worked on developing missile guidance systems and on ultrasound instruments for medical use.

He died on 21 October 2001.

Family He was married to Jean Williamson. They had one daughter and three sons.