Possibly the most unusual post I’ve written, the Pitch Drop Experiment is the world’s longest running lab experiment according to Guinness.
Notice how large of a drop that is in the picture there. Pitch is a rather peculiar substance. It appears solid and can be shattered with a hammer. But some folks argued that it was indeed a highly viscous liquid, and in 1927 a fella by the name of Thomas Parnell set up this simple experiment to prove it.
It took eight years for the first drop to fall. The second took nine.
It has dropped every 8 to 9 years since, and the pitch has now dripped eight times in the last 79 years. With some quick back-of-the-envelop calculations, that makes it approximately 230 billion times more viscous than water. The last time was in 2000, which by my reckoning was 9 years ago — meaning we’re due. If you’d like to watch in the hopes that you can say, “I was there when the pitch dropped!”, there’s a webcam set up here: mms://drop.physics.uq.edu.au/PitchDropLive. [You’ll have to copy/paste for yourself. WordPress is uncooperative once again.] That webcam was set up before the last time in 2000, but there was a technical problem and it missed the drip. So no one has ever actually witnessed a drip!
If you’d like to see this for yourself, just drop in at the University of Queensland in Brisbane, Australia. [Heh! Drop in! Get it? I’m so clever…] Not visiting there for a while? I’m sure it’ll still be going. There’s enough pitch left in the funnel to last another 100 years.
[Inspiration for (blatant theft of) this article came from Atlas Obscura, which is just an awesome website all the way around.]