Pitch drop experiment

At room temperature, tar pitch flows at a very low rate, taking several years to form a single drop.

The best-known version[1] of the experiment was started in 1927 by Thomas Parnell of the University of Queensland in Brisbane, Australia, to demonstrate to students that some substances which appear solid are highly viscous fluids.

[1] The eighth drop fell on 28 November 2000, allowing experimenters to calculate the pitch as having a viscosity of approximately 230 billion times that of water.

This experiment is predated by two other (still-active) scientific devices, the Oxford Electric Bell (1840) and the Beverly Clock (1864), but each of these has experienced brief interruptions since 1937.

The experiment was not originally carried out under any special controlled atmospheric conditions, meaning the viscosity could vary throughout the year with fluctuations in temperature.

[8] Mainstone subsequently commented: I am sure that Thomas Parnell would have been flattered to know that Mark Henderson considers him worthy to become a recipient of an Ig Nobel prize.

[7] The pitch drop experiment is on public display on Level 2 of Parnell building in the School of Mathematics and Physics at the St Lucia campus of the University of Queensland.

This physics experiment sat on a shelf in a lecture hall at Trinity College unmonitored for decades as it dripped a number of times from the funnel to the receiving jar below, also gathering layers of dust.

[17][18][19] In April 2013, about a decade after the previous pitch drop, physicists at Trinity College noticed that another drip was forming.

They moved the experiment to a table to monitor and record the falling drip with a webcam, allowing all present to watch.

The University of Queensland pitch drop experiment, demonstrating the viscosity of bitumen .
The University of Queensland pitch drop experiment, featuring its custodian, John Mainstone (taken in 1990, two years after the seventh drop and 10 years before the eighth drop fell).
Kelvin's glacier model