World’s slowest experiment – Pitch Drop

It’s the scientific equivalent of the 639-year-long recital of John Cage’s “As Slow As Possible” (a performance of which in Germany is currently in its 11th year and with a new note due on 5 July). In 1927, … yes, 1927 ….Professor Thomas Parnell, the first physics professor at Australia’s University of Queensland, decided to create an experiment to demonstrate the surprising properties of everyday objects. In this case, he wanted to demonstrate that pitch, a derivative of tar which looks and feels solid (and can even be smashed with a hammer), can actually display the properties of a liquid. Parnell took a heated-up sample of pitch, put it into a sealed funnel for three years and then removed the seal to see whether the pitch would drip.

The eighth drop fell on 28 November 2000, allowing experimenters to calculate that the pitch has a viscosity approximately 230 billion (2.3×1011) times that of water. The ninth drop is expected to fall in 2012 or 2013.

Is it really the worlds longest running experiment? Well, it is recorded in the Guinness Book of Records as the world’s longest continuously running laboratory experiment, and it is expected that there is enough pitch in the funnel to allow it to continue for at least another hundred years. Ah but … this experiment is pre-dated by two other still-active scientific devices, the Oxford Electric Bell (1840) and the Beverly Clock (1864), so while it might indeed be the slowest, I don’t think it is the longest running.

Want to find out more? You can do so here.

Interested in watching? There have a webcam here (but don’t hold your breath waiting for a drop)


Date Event Duration(months) Duration(years)
1927 Experiment set up
1930 The stem was cut
December 1938 1st drop fell 96–107 8.0–8.9
February 1947 2nd drop fell 99 8.3
April 1954 3rd drop fell 86 7.2
May 1962 4th drop fell 97 8.1
August 1970 5th drop fell 99 8.3
April 1979 6th drop fell 104 8.7
July 1988 7th drop fell 111 9.3
28 November 2000 8th drop fell 148 12.3



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