Trinity College Dublin

Skip to main content.

Top Level TCD Links


NATURE: World's Slowest-Moving Drop Caught on Camera at Last

Pitch Tar Drop Experiment Trinity College Dublin

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 2x107 Pa s - approximately 2 million times the viscosity of honey.

Time-lapsed video of the Pitch-Tar Drop experiment:

Media Coverage

How long would you be willing to wait for a drop of the black stuff in Dublin?

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.

- Richard Johnston, NATURE JOURNAL

NATURE article can be found here.

RTE have a covered the experiment which can be viewed on the RTE Player. The RTE news article can be found here: RTE News Article

CNET article can be found here: CNET News Article

Huffington Post article can be found here: Huffington Post Article

NBC Bay Area article can be found here: NBC Bay Area Article

Business Insider article can be found here: Business Insider

Science blog "Let's Talk about Science!" have written an article about the experience: Let's Talk about Science.

Daily Mail article can be found here: Daily Mail Article article can be found here: Article

The Register article can be found here: The Register Article

Last updated 19 July 2013 (Email).