World’s Slowest (and Oldest) Scientific Laboratory Experiment

Saturday, May 04, 2013
John Mainstone watching pitch drop (photo: University of Queensland)

Witnessing a scientific experiment in action is not something researchers have experienced at Queensland University in Australia, despite the fact that the work has gone on for 86 years.


In 1927, physics Professor Thomas Parnell set up the pitch drop study, which as its name describes, involves watching a glob of pitch as it slowly releases droplets of the thick substance out of a glass funnel. Very slowly.


The pitch, a derivative of tar once used for waterproofing boats, is so slow that a grand total of only eight drops have been produced since the stem of the funnel was cut in 1930. The drops fell in 1938, 1947, 1954, 1962, 1970, 1979, 1988 and 2000. Unfortunately, no one involved with the study has seen a drop in action, including Professor John Mainstone, who has run what is thought to be the world's oldest laboratory experiment since 1961.


“No one has actually seen a drop emerge, so it is getting quite nervy round here,” Mainstone told The Observer. “The other eight drops happened while people had their backs turned. For the last drop, in 2000, we had a webcam trained on the experiment, but it broke down….In 1988, when the previous drop was about to emerge, I popped out for a coffee and missed it.”


But Mainstone may finally get his chance, saying he expects another drop in the near future. This time, the lab has set up three web cameras to record the event.


The point of the experiment has been to determine the viscosity of pitch, considered the world’s stickiest substance. It is at least 230 billion times more viscous than water, researchers say. In fact, at room temperature, pitch feels solid and brittle, so much so that it can easily be shattered with a hammer. According to the web site of The University of Queensland’s School of Mathematics and Physics, “It's quite amazing then, to see that pitch at room temperature is actually fluid!”

-Noel Brinkerhoff


To Learn More:

World's Oldest and Stickiest Lab Study Ready for Drop of Excitement (by Robin McKie, The Observer)

World's Oldest Experiment Ready For A Drop of Excitement (by Katie Hunt, CNN)

The Pitch Drop Experiment (University of Queensland, Australia) (Live Webcam)

The Pitch Drop Experiment (by R. Edgeworth, B.J. Dalton and T. Parnell, of Queensland)


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