Begun in October 1944, the Tar 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 tar, or pitch, is a material that flows – albeit it with an incredibly high viscosity. Whilst pitch has been dropping from the funnel since 1944, nobody has ever witnessed a drop fall – they happen it happens roughly only once in a decade!
In May of this year, with the latest drop about to fall, Prof. Shane Bergin broadcast the experiment via the web. On July 11th, 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 2×107 Pa s – approximately 2 million times the viscosity of honey.
Credit: Trinity College Dublin
[ Read the Article: Seven Decade-Long Experiment Catches Tar Dripping For First Time ]