Pitch drop experiment
The pitch drop experiment is a long-term experiment which measures the flow of a piece of pitch over many years. Pitch is the name for any of a number of highly viscous liquids which appear solid, most commonly bitumen. At room temperature, tar pitch flows at a very slow rate, taking several years to form a single drop.
University of Queensland experiment
The most famous version of the experiment was started in 1927 by Professor Thomas Parnell of the University of Queensland in Brisbane, Australia, to demonstrate to students that some substances that appear to be solid are in fact very-high-viscosity fluids. Parnell poured a heated sample of pitch into a sealed funnel and allowed it to settle for three years. In 1930, the seal at the neck of the funnel was cut, allowing the pitch to start flowing. A glass dome covers the funnel and it is placed on display outside a lecture theatre. Large droplets form and fall over the period of about a decade.
This is recorded in Guinness World 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. 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 have experienced brief interruptions since 1937.
The experiment was not originally carried out under any special controlled atmospheric conditions, meaning that the viscosity could vary throughout the year with fluctuations in temperature. Some time after the seventh drop fell in 1988, air conditioning was added to the location where the experiment takes place. The temperature stability has lengthened each drop's stretch before it separates from the rest of the pitch in the funnel.
Professor 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. Professor Parnell's award citation would of course have to applaud the new record he had thereby established for the longest lead-time between performance of a seminal scientific experiment and the conferral of such an award, be it a Nobel or an Ig Nobel prize.
The experiment is monitored by a webcam but technical problems prevented the November 2000 drop from being recorded. 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. Hundreds of thousands of internet users are checking the live stream each year.
|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||8.2|
|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||9.2|
|28 November 2000||8th drop fell||148||12.3|
Trinity College, Dublin experiment
- William James Beal, Botanist who started a long-running seed germination experiment in 1879
- Trent Dalton (6 April 2013). "Pitch fever". The Australian (News Limited). Retrieved 9 July 2013.
- Edgeworth, R., Dalton, B.J. & Parnell, T. "The Pitch Drop Experiment". Retrieved 2007-10-15.
- The 2005 Ig Nobel Prize Winners. Improbable Research. Retrieved 6 July 2013.
- Mainstone, John. "A Comment from Professor Mainstone". University of Queensland. Retrieved 5 November 2012.
- University of Queensland page on the Pitch Drop experiment
- Link to Webcam
- "Professor in charge of famous 'Pitch Drop' experiment for 50 years dies waiting to see it in action". NY Post. Retrieved 27 August 2013.
- "The 3 Most Exciting Words in Science Right Now: 'The Pitch Dropped'". RTE News Ireland. 19 July 2013. Retrieved 19 July 2013.
- [Megan] (18 July 2013). "Trinity College experiment succeeds after 69 years". The Atlantic. Retrieved 19 July 2013.