John Henry Poynting

Who was John Henry Poynting?

John Henry Poynting was an English physicist. He was a professor of physics at Mason Science College, from 1880 to 1900, and then the successor institution, the University of Birmingham until his death.

Poynting was the youngest son of Thomas Elford Poynting, a Unitarian minister. In his boyhood he was educated at a school operated by his father. From 1867 to 1872 he attended Owen's College, now the University of Manchester, where his physics teachers included Osborne Reynolds and Balfour Stewart. From 1872 to 1876 he was a student at Cambridge University, where he attained high honours in mathematics after taking grinds with Edward Routh. In the late 1870s he worked in the Cavendish Laboratory at Cambridge under James Clerk Maxwell.

He was the developer and eponym of the Poynting vector, which describes the direction and magnitude of electromagnetic energy flow and is used in the Poynting theorem, a statement about energy conservation for electric and magnetic fields. This work was first published in 1884. He performed a measurement of Newton's gravitational constant by innovative means during 1893.