Poynting was a physicist who is best known for his work on electromagnetism. He found that the energy carried by an electromagnetic wave can be described by a vector given by the cross product of the electric field and the magnetic field. This vector is known today as the Poynting Vector.
He also lends his name to the Poynting-Robertson effect. This describes the capture of dust particles by a star. The radiation from the star slows the nearby particles as it hits them, thus they slowly spiral into the star, emptying the star system of dust.
Poynting worked on the gravitational constant (big G.) The torsion balances he used to determine the value of big G can still be seen in the University of Birmingham physics tearoom. Poynting worked at this university from 1880 until his death in 1914. When he started there it was still known as the Mason Science College. He started the university's study of radioactivity, a field in which the physics department is still very active to this day. Previous to his appointment in Birmingham he was educated at Cambridge and Manchester universities, being born in Monton, near Manchester.