What is the longest scientific study in history?
This is a fun question to answer. The University of Queensland (Australia) currently holds the world record for the longest running experiment. The experiment’s creator was Professor Thomas Parnell, the first professor of physics, who in 1927 set up the experiment to demonstrate the viscosity of pitch – the thickest fluid known to man.
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.
Professor Parnell heated some pitch and poured it into a glass funnel with a sealed stem, and left it to cool. After three years, the bottom of the funnel was cut and the pitch began to flow downwards.
It took from seven to nine years for each drop to fall. The eighth drop took more than 12 years to fall, perhaps due to lower pressure from the diminishing mass of pitch remaining in the funnel. Or maybe the air conditioner installed in the 1980s made the pitch cooler and even more viscous.
Since the pitch drop experiment began in 1930 no one has ever seen the pitch actually drop. The ninth drop actually stuck to the eighth.
The ninth drop was such an exciting event that that over 30,000 people around the globe from 158 countries registered to view a live video stream as to the exact moment of the drop’s touchdown. Now instead of the phrase “I’d rather watch grass grow” or “I’d rather watch paint dry” you can also say “I’d rather watch pitch fall”. You’d be mistaken to think nothing exciting happens in Australia. The drop finally occurred on April 12 2014.
Based on the first six drops, the viscosity of the pitch was estimated to be about 250 billion times that of water. But the tenth drop is for some reason, less viscous, only 30 billion times that of water. It turns out the fluorescent down-light in the display cabinet heated up the pitch a little and made it flow faster.
In 2005, Professor Thomas Parnell was posthumously awarded the Ig Nobel Prize in Physics.