I recently learned that tennis balls became yellow in the early 1970s. This change was made after research showed that yellow balls were more visible to both players and spectators, especially on color television broadcasts. Before this, tennis balls were traditionally white, making them difficult to see against the court surface. The International Tennis Federation (ITF) made the official switch to yellow tennis balls in 1972, and since then, they have become the standard color used in professional tournaments worldwide. It's fascinating how a simple color change can have such a significant impact on the sport!