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Pitch Tar Drop

After 69 years, one of the longest-running laboratory investigations in the world has finally captured the fall of a drop of tar pitch on camera for the first time.

Begun in October 1944, the Pitch Drop experiment, at Trinity College Dublin's School of Physics, is one of the world's oldest continuously running experiments.

This curiosity of an experiment demonstrates that pitch is a material that flows - albeit it with an incredibly high viscosity. Whilst pitch has been dropping from the funnel since 1944, nobody had ever witnessed a drop fall - they happen it happens roughly only once in a decade! In May 2013, with the latest drop about to fall, Prof. Shane Bergin broadcast the experiment via the web. On July 11th 2013, the drop dripped. You can see a time lapse video of this here. Tracking the evolution of the drop, Profs. Weaire & and Hutzler, and Mr. David Whyte calculated the viscosity of the pitch to be 2x107 Pa s - approximately 2 million times the viscosity of honey.

The time-lapse video has attracted considerable global media attention. Discover Magazine named the Trinity Pitch Drop in their top 100 science stories of 2013 and a feature article in Nature News was the 3rd most-read piece on their website in 2013.

Pitch Tar Drop in the Media