Patiently Preparing for the Pitch Drop

Shattered pitch with hammerA career as a scientist is many things: it is fascinating, ever-evolving, intense. Whatever images came to your mind when reading those words are probably nothing like the images a scientist would paint for you about his/her work day. Along with investigation and discovery, one of the major themes in a scientific career is patience. Some experiments are faster than other, e.g. one assay to measure enzyme kinetics can take less than seconds to achieve results (not including prep time), whereas it may take months to observe a mouse phenotype that may or may not change following a gene mutation. No matter what the experiment, scientists spend a considerable portion of their careers waiting.

However, no amount of waiting I have experienced in my scientific career can quite compare to the waiting that must be endured by the scientists monitoring the Pitch Drop Experiment in progress at the University of Queensland in Australia. Pitch, which is a derivative of tar, appears to be a solid and even brittle at room temperature. In 1927, scientist Thomas Parnell decided to create a demonstration to show that things are not always what they seem.  He heated up some pitch and placed it in a glass funnel with the bottom fused so it could not leak through. Professor Parnell let the pitch settle into its new formation for a full three years (!) at which point he cut the bottom of the funnel stem and the experiment began to prove that pitch is a highly viscous liquid. Now here is an important lesson about patience and perseverance: the first drop did not fall from the funnel until 1938- a full eight years after the stem was cut! 86 years after the Pitch Drop Experiment began, only eight drops have fallen from that funnel, about one drop each decade. A record and proposal for modeling pitch drops can be found here:

Professor Mainstone with Pitch Drop experiment
Professor Mainstone with Pitch Drop experiment

Professor John Mainstone began supervising Queensland’s Pitch Drop Experiment in 1961. He missed drop seven by about five minutes when he stepped out for a refreshment. Although a camera was set up to capture the eighth drop fall in 2000, equipment malfunctioned while Professor Mainstone was overseas and the data were lost. Sadly, Professor Mainstone passed away in August of 2013 without ever witnessing a drop fall.

No one has ever witnessed the drop of pitch actually fall from the funnel, but you could be the first! In, perhaps, the best way to help non-scientists understand the excitement of waiting, there is a live webcam recording “The Ninth Drop” as it descends into the beaker below. It was expected to fall in late 2013 (13 years after drop 8), but is still hanging on.  If you want to be part of history, be sure to register on the website!

Researchers in Dublin, who began a similar pitch drop experiment in 1944, scooped the Queensland scientists. They first witnessed a drop of pitch fall from their funnel in July of 2013 collecting the first official evidence that pitch is, indeed, a liquid. You can catch a time lapse video of the drop falling below.

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Karen Reece

Senior Research Scientist at Promega Corporation
Karen is a Senior Research Scientist in Nucleic Acid Technologies at Promega. She has a BS in Biochemistry and MS and PhD in Physiology, all from University of Wisconsin-Madison. Karen was born and raised in Madison, WI and every time she would think of moving away something would come up, so she just decided to stay. When she’s not doing research and/or development, Karen enjoys the local music scene (particularly Hip-Hop), playing the cello and singing, and fighting for social justice.

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