Answer: A Jar of Pitch

The longest running experiment in the history of modern science is a simultaneously interesting yet stupendously boring one that, despite peoples best efforts, has never actually been directly observed.

In 1927 at the University of Queensland, one Professor Thomas Parnell patiently began a long-term experiment in order to prove to his students that some substances which appear to be solid are actually extremely high-viscosity fluids. These fluids appear solid at room temperature and, when struck with a hammer, will even shatter, but will in fact move and reform over extended periods of times. Demonstrating such movement is a task for the steadfast.

To that end Dr. Parnell heated a sample of pitch (the bitumen variety historically used to waterproof ships), poured it into a sealed glass funnel, waited three years for it to settle, and then in 1930 he broke the seal to begin the flow process.

Over eight years later, in December of 1938, the first drop fell. Another eight years after that, in 1947, the second drop fell. All told, the experiment has been running nearly a century and a scant 8 drops have fallen. While pitch might be viscous, its viscosity is a staggering 230 billion times that of water. Entire empires could rise and fall before a pitch drop experiment finished filling a gallon jug.

Currently, the experiment is curated by the School of Mathematics and Physics on the University’s St. Lucia campus. The temperature controlled environment of the building it is on display in has slowed the rate of movement to one drop roughly every 12 years. The last drop fell in the fall of 2000 which means we’re due for a new drop any day now–for those of you looking for a cheap and slow-moving thrill, the University has a web cam trained on the experiment at all times.