The St Mary Redcliffe Chaotic Pendulum

Among the many things to see and do in Bristol, a visit to St Mary Redcliffe is undoubtedly right at the top. Queen Elizabeth I said this church was “The fairest, goodliest and most famous parish church in England.”

A pendulum is usually a symbol of predictability and regularity, but this one exhibits chaotic behavior due to its sensitive dependence on initial conditions. The chaotic pendulum at St Mary’s is believed to be unique in design, and maybe the only device of its kind. As recycled water is continually pumped into the crossbeam, causing it to tip one way or the other to let it flow out again.

It was unveiled on September 25th, 1997, and was constructed and designed by Rob Knight of Op-Ticks in Bristol. The original idea for the contraption was conceived by Sir Brian Pippard FRS, former Cavendish Professor of Physics at Cambridge University, who was also an advisor to its implementation. Dr. Eric Albone is credited with having the idea to bring the apparatus to the church. 

Even if a completely accurate mathematical model could be built, any readings taken from the real pendulum would contain errors.