It has taken me a long time to get around to this post, but that’s all right. It’s not as if the story is going to go cold. Or any colder, anyway. It might be two years since the last significant development in the pitch drop experiment, but it will probably be twelve more before the next one.
This pitch drop experiment (there are others) was begun in 1927 at the University of Queensland in Brisbane, by Professor Thomas Parnell. There is another pitch drop experiment running at Trinity College in Dublin, which was begun in 1944, but it hasn’t been continuously monitored. It has accumulated several drips unobserved, so its data are incomplete. It did catch its most recent drip on camera, though, with time-lapse photography. Yet another experiment has been unearthed in Wales. That one started in 1914, even before the Australian one, but it has yet to produce its first drip. One has to admire the dedication of researchers who stick with an experiment that will still be running long after they’re dead. It even has its own YouTube channel.
With no data from Wales and incomplete data from Ireland, the only useful data come from the Australian experiment. Using those data, they have calculated that their pitch, under their conditions, is 230 billion times as viscous as water.
Since Professor Parnell initially began the pitch drop experiment to demonstrate to his students that apparently solid substances can simply be highly viscous liquids, I’d say the experiment is a success. Unfortunately, given that it’s almost 90 years later, it’s probable that his students are dead