An experiment in patience
In 1927, Professor Thomas Parnell of the University of Queensland initiated an experiment to show that some materials are not what they seem. He took a sample of pitch—a tar derivative so brittle it can be shattered with a hammer at room temperature—and gently heated it. He poured the warm, thick liquid into a glass funnel with a sealed stem. For three years, the pitch was left to settle. In 1930, Parnell cut the stem of the funnel, allowing gravity to begin its slow work.
The setup is simple: the glass funnel sits above a beaker, all enclosed within a glass bell jar to keep out dust. The experiment's goal was to show that pitch is not a solid, but an extremely viscous fluid. The results are clear. The pitch has a viscosity calculated to be about 100 billion times that of water. The first drop fell from the funnel in December 1938, eight years after the stem was cut. To date, only nine drops have fallen. The intervals between drops originally averaged eight to nine years, but the installation of air conditioning in the building slowed the flow, extending the wait to around 12 or 13 years per drop.
The impossible observation
Despite nearly a century of operation, no person has ever directly witnessed a drop separate from the funnel. Professor Parnell died in 1948, having seen only two drops fall, neither in the act. His successor, John Mainstone, became the experiment's custodian in 1961 and watched over it for 52 years. Mainstone missed the sixth drop in 1979 because it fell over a weekend. He missed the seventh in 1988 while at Brisbane's World Expo 88; he had stepped away to get a drink at the moment it happened. For the eighth drop in November 2000, a webcam was installed, but a technical glitch prevented it from recording the event.
The ninth drop was the most documented, finally separating in April 2014. It was captured by multiple cameras, but it landed in the beaker which already held the previous eight drops. Before the tenth drop forms, the old beaker was replaced with a fresh one. John Mainstone passed away in August 2013, never having seen a drop fall in his 52 years of custodianship. The experiment, now under the care of its third custodian, Professor Andrew White, continues its slow and steady experiment. There is enough pitch remaining in the funnel for it to continue for at least another century.