The Liberty Bell, which has not been rung in 180 years, has been the subject of scientific inquiry regarding its original sound. In recognition of the nation's 250th anniversary, researchers at Penn State University have created models of the bell's acoustic properties using data from one of its replicas. This research was presented at a meeting of the Acoustical Society of America in Philadelphia earlier this year and subsequently published in Physics Today.
Historians are uncertain about the exact timing of the Liberty Bell's distinctive crack, which is believed to have occurred between 1817 and 1846. An account from the Public Ledger in 1846 noted that the bell rang on February 23 of that year and had developed a crack that someone attempted to repair by filing down the sides. This attempt was unsuccessful, and the ringing on February 23 further extended the crack, leading to the description of the bell as "irreparably cracked and forever dumb." The bell has not been heard since.
The Liberty Bell has a history of cracking; it first cracked shortly after its arrival in Philadelphia in 1752 when the clapper struck during a sound test. It was recast twice by local foundry workers John Pass and John Stow, as the initial recast produced an unsatisfactory sound, described by a bystander as resembling coal scuttles banging together.