Tyndall

Part of speech: noun

Definitions

1. The scattering of a light beam by tiny particles suspended in a fluid, which makes the beam's path visible ; the Irish scientist of the 1800s known for research on heat, light and magnetism
2. The visible scattering of light passing through a colloid or fine suspension ; a nineteenth-century Irish physicist famed for experiments on radiant heat and light
3. Light that is scattered by particles in a mist, smoke or colloid so that its path shows ; the surname of an Irish physicist of the Victorian era who studied radiant heat

Etymology: Tyndall is a variant spelling of Tynedale, the valley of the River Tyne in Northumberland, northern England. "Dale" is the ordinary English word for a valley, so the name means roughly "the dale of the Tyne." The river's own name is older and of uncertain origin. The spelling later settled into a surname, often carried by families who took it from the place where they lived. The spelling is now best known from the Irish physicist John Tyndall, whose studies of light scattering gave his name to the Tyndall effect. That is the bluish glow of fine particles suspended in a liquid or gas, and it is why a sunbeam through dusty air becomes visible.