Little Bits of History

The Pitch Experiment

Posted in History by patriciahysell on November 28, 2010

The University of Queensland pitch drop experiment, demonstrating the viscosity of bitumen.

November 28, 2000: The eighth drop in The Pitch Experiment falls. Professor Thomas Parnell began the experiment in 1927 at the University of Queensland in Brisbane, Australia. The goal of the experiment was to show that some substances that appear to be solids are in fact, liquid. Pitch is a viscous, slow-moving liquid, usually bitumen. Tar pitch flows at room temperature. Slowly. Very, very slowly.

The pitch was placed in a sealed funnel by Professor Parnell and then allowed to settle. Three years later, it was deemed to have settled and the tip of the funnel was opened and the liquid was now allowed to flow. It eventually formed a drop that fell into the receptacle beneath. Pitch will shatter when struck with a hammer, seeming solid, but it flows as a liquid. There were no controls set and the flow of the liquid remains affected by temperature.

The first drop fell during December of 1938, the second in February 1947. Professor Parnell died in 1948 and the experiment came under the supervision of John Mainstone. The next drops fell April 1954, May 1962, August 1970, April 1979, July 1988, and finally November 2000. No one has ever seen a drop actually fall. There was a webcam set up filming the experiment in 2000, but it malfunctioned at the critical time.

Parnell and Mainstone were awarded the Ig Nobel Prize, a parody of the Nobel Prize, which is awarded for efforts that at first seem silly and yet eventually make you think. Mainstone accepted the award. He has since stated that there is enough pitch for the experiment to continue for at least another 100 years, if someone can watch over it. Not exactly a time-consuming task. Back when the experiment was set up, it was not considered that the rooms would be air conditioned. They have been. The last drop was the largest drop ever seen and the receptacle was not of sufficient size for it to allow for the drop to entirely break from the funnel. There does need to be some modifications. The tests seem silly, but they have given help to the study of viscosity and shown that pitch is 100 billion times more viscous than water.

“It is the sort of experiment that does require patience.” – John Mainstone

“Patience is the companion of wisdom.” – Saint Augustine

“You must first have a lot of patience to learn to have patience.” – Stanislaw J. Lec

“The chemist who can extract from his heart’s elements compassion, respect, longing, patience, regret, surprise, and forgiveness and compound them into one can create that atom which is called love.” – Kahlil Gibran

Also on this day, in 1942 the Cocoanut Grove fire destroys the nightclub and kills 492 patrons.


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