Pitch Drop experiment
smp.uq.edu.au

... We're home to the famous Pitch Drop experiment, which holds the Guinness World Record for the longest-running laboratory experiment.

The experiment demonstrates the fluidity and high viscosity of pitch, a derivative of tar that is the world's thickest known fluid and was once used for waterproofing boats.

Thomas Parnell, UQ's first Professor of Physics, created the experiment in 1927 to illustrate that everyday materials can exhibit quite surprising properties.

At room temperature pitch feels solid - even brittle - and can easily be shattered with a hammer. But, in fact, at room temperature the substance -- which is 100 billion times more viscous than water -- is actually fluid. ...

www.guinnessworldrecords.com

... Once the stem of the funnel was cut, the pitch slowly began to drip. In late 2000, the 8th drop fell. From this experiment it has been possible to demonstrate that the viscosity of pitch is about 100 billion times that of water. There is enough pitch still in the funnel for this famous experiment to run for another hundred years. ...