A disco ball, also known as a ball mirror, is a large sphere covered with numerous glass mirror pieces or other reflective material. The entire disco ball is usually suspended above the heads of dancers in a club. Once a spotlight is focused on the rotating ball, random streaks of light are projected onto the walls, ceiling and floor. A variable speed motor controlled by the DJ or lighting technician can change the speed and direction of the disco ball as it spins.
The mirrored dance ball actually predates the 'disco ball' by several decades. An early version can be seen in the movie Casablanca, for instance. When discotheques experienced a revival in the 1970s, creative lighting once again became an important part of the overall ambience. The random flashes of light generated by a disco ball created a dynamic background for other effects such as strobes and helicopter lights. As the disco culture became part of mainstream society, the disco ball became shorthand for a glitzy, upbeat club atmosphere.
When the popularity of disco waned in the early 1980s, the disco ball went with it. Some ballrooms still maintained a very large mirror ball to indicate an open dance floor, but the frenetic pace of a disco ball became more of a relic of a bygone era. By the late 1990s, however, a new generation of 'house music' enthusiasts revived many of the lighting and sound effects of the dance clubs, including the disco ball.
Today, those interested in owning a disco ball can order one through specialty gift stores, internet catalogs and theatrical lighting outlets. Large professional units with thousands of real mirrors can still run into the hundreds or even thousands of dollars, but some novelty varieties cost only ten to twenty dollars. The important thing to remember when hanging a disco ball is to provide a focused form of lighting, such as a pinspot or even a flashlight. Colored lights will produce color reflections, which may be more visually appealing.
For the craftier disco enthusiast, a perfectly useful disco ball can be created with a collection of unwanted CDs and a large foam sphere. Plans for this type of project can be found online or in do-it-yourself craft books. Other homemade disco ball ideas can also be found online, using everyday components such as latex balloons and reflective tape.