During which decade did mirror or glitter balls first make an appearance in nightclubs?

A mirror or glitter ball in the1920s was decades later called a disco ball. It is a spherical object that reflects light directed at it, outward in multiple directions, producing a complex display. Its surface consists of hundreds or thousands of facets, nearly all of approximately the same shape and size, and each having a mirrored surface to reflect the light.

The balls are usually mounted well above the heads of the people present, suspended from a device that causes it to rotate steadily on a vertical axis while illuminated by spotlights, so that stationary viewers experience beams of light flashing over them, and see myriad spots of light spinning around the walls and floor of the room.

The unique balls were first widely used in nightclubs in the 1920s. An early example can be seen in the nightclub sequence of ‘Berlin: Symphony of a Metropolis’ (English translation), a German silent film from 1927.

In the 1960s, 1970s, and 1980s, these devices were a standard piece of equipment in discotheques, and by the turn of the millennium, the name disco ball had grown quite popular.

A Louisville, Kentucky company currently known as Omega National Products claims to have made 90% of the disco balls used in the United States during the disco craze- remaining a supplier in 2022.