It just so happens that three of the longest running scientific experiments are located in the foyers of university physics departments. These three long-running tests were first reported as a set in a 1984 article in the European Journal of Physics. One of them, the pitch drop has achieved some internet fame. But it is not the oldest. The oldest experiment is the Oxford bell and it has been running about 160 years. All three were later updated in the Annals of Improbable Research in this 2001 article:
We are happy to report that three of the world’s longest-running scientific experiments are indeed still running. It has been a number of years since anyone checked on all three. With assistance from scientists in several nations, we have managed to do so.
In 1984, the European Journal of Physics published three remarkable reports, each describing a different experiment that had been continuing for decades. The youngest — the pitch drop viscosity experiment at the University of Queensland in Brisbane — had been started in 1927. The oldest — the now-and-then-famous Oxford electric bell at Oxford University, was begun in 1840. The third experiment, the Beverly clock at the University of Otago in Dunedin, was commenced in 1864.
