Nature takes a quick look at the now-86-year-long pitch drop experiment, and at several other long-running experiments. The people who started and tend the pitch drop experiment were awarded the 2005 Ig Nobel Prize in physics. Nature says, in part:
The pitch-drop experiment started when Thomas Parnell, the university’s first professor of physics, set up a demonstration for his students to show that a sample of pitch, a black tar distillate that is brittle enough to shatter with a hammer when cold, will act like a liquid and flow through a funnel, dripping out of the bottom like the world’s slowest hour glass. It did, at a rate of about one drop every 6–12 years. Mainstone expects — cautiously — the ninth drop to fall sometime towards the end of this year.
The experiment is not exactly a hotbed of discovery. In 86 years, it has yielded exactly one scientific paper, which calculated that the pitch was 230 billion times more viscous than water….