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The Pitch Drop Experiment; said to be the longest running laboratory experiment, has been running for the past 70 years and has got to be one of the most bizarre and wacky pieces of science I've heard of in a long time.

At its heart lies a funnel, under sealed glass bell jar, that contains pitch (a form of tar) at room temperature. At room temperature pitch in fact feels as solid as rock, and shatters like glass when hit with a hammer, but it is in fact a liquid!

In 1927 the physicist Professor Thomas Parnell in the University Of Queensland, Brisbane started the experiment to prove that this was the case. He warmed some pitch up, dropped it into into a sealed glass funnel and left it to settle for three years. Then in 1930, the bottom was cut off the funnel, and the stop watch started so as to time how long the drops took to fall....

The first one fell 8 years later!
The second fell in 1947...
The third in 1954...
The fourth in 1962...
The fifth in 1970...
The sixth in 1979...
The seventh in 1988...
The eighth in 2000

So far nobody has managed to see a drop actually fall; but now thanks to the wonders of modern technology there's a web-cam set up, so you could see the next drop fall, and be part of scientific history. I haven't heard if anybody saw the 2000 drop, drop, via the web-cam however, and it looks like a long wait to the next one! The consenus is that there's about another 100 years left in the experiment, so you still have a chance.

The experiment has given a result that Professor Parnell would no doubt be most gratified to hear of (he died in 1948, not long enough for good data to be collected), that pitch is 10,000,000,000 times more viscous than water!

A similar experiment was began at about the same time in 1927 at the University of St. Andrews in Scotland, seemingly without correspondence between the two groups. However whereas the Queensland experiment has formed nice well shaped drops, the one at St. Andrews has just dribbled out. Probably this is due to this sample of pitch having a higher proportion of volatile hydrocarbons; pitch is well known for being rather non-uniform, with each sample having a slightly different compostion. Another variation on the theme is an experiment in Glasgow Univeristy started by Lord Kelvin where a block of pitch was placed at the top of a wooden slide, and over the years has slowly dribbled down it.

Source :- UK Daily Mail June 6, 2001 James Chapman (author)
And CamTarn who pointed out the Glasgow experiment!
And many others here for proof reading and googling up the link to the web-cam :-
http://www.physics.uq.edu.au/pitchdrop/pitchdrop.shtml

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