The worlds most viscous fluid
I came across this interesting article from the University of Queensland, Australia. It's about this substance that seems like it's rock, but it's actually fluid.
Quote:
The first Professor of Physics at the University of Queensland, Professor Thomas Parnell, began an experiment in 1927 to illustrate that everyday materials can exhibit quite surprising properties. The experiment demonstrates the fluidity and high viscosity of pitch, a derivative of tar once used for waterproofing boats. At room temperature pitch feels solid - even brittle - and can easily be shattered with a blow from a hammer (see the RealVideo® clip below). It's quite amazing then, to see that pitch at room temperature is actually fluid!
The professor made an experiment and but the pitch inside a container with a hole in the bottom, to see if it would drip. Since the start of the experiment (1927) there have been 7 drops of pitch from the container. That's one drop every 10 years!
On this page you can even see a video (in relplayer format) about the experiment: http://www.physics.uq.edu.au/pitchdrop/pitchdrop.shtml
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