The bouncing ball is a device used in video recordings to visually indicate the rhythm of a song, helping audiences to sing along with live or prerecorded music. As the song's lyrics are displayed on the screen, an animated ball bounces across the top of the words, landing on each syllable when it is to be sung.
The bouncing ball is mainly used for English language songs in video recordings; however, in Japan, a similar device is used where the text changes color as it is sung, just like in karaoke.
The bouncing ball technique was invented by Max Fleischer originally for the "Ko-Ko" Song Car-tunes (1924–1927) and revised in 1929 as Screen Songs (1929–1938) for Paramount. It was introduced in March 1924 with the film Come Take a Trip in my Airship.
In early Song Car-Tunes such as "Margie" and Irving Berlin's "When the Midnight Choo-Choo Leaves for Alabam'" the ball is animated, looking like a beach ball clumsily hitting the words without precise timing. This awkwardness was eliminated by filming the ball live over printed lyrics, and the ball attached to a black baton that "bounced" a white disc over the tops of the lyrics. The movement was captured on high-contrast film that rendered the stick invisible. The ball would usually appear as white-on-black, though sometimes the ball and lyrics would be superimposed over (darkened) still drawings or photographs or even live-action footage.
While the Screen Song series started out employing standard songs such as "Yankee Doodle Boy", "My Pony Boy", and "Yes! We Have No Bananas", the series soon integrated live action appearances of celebrities of Broadway, radio, and recordings. Many of these Screen Songs were planned as promotions for live theatrical appearances. This was part of a new marketing plan launched by Paramount for the 1930–1931 season. Rudy Vallee was the first on-screen celebrity, appearing in "Betty Co-Ed" (1931), and returned in "Kitty From Kansas City" (1931). He also appeared in a cameo in "Rudy Vallee Melodies" (1932). Other celebrities included Arthur Tracy in "Russian Lullaby" (1931) and "Romantic Melodies" (1932), Ethel Merman in "Let Me Call you Sweetheart" (1932), "You Try Somebody Else" (1932), "Time on my Hands" (1932), and "Song Shopping" (1933).