Scientific experiments can take a few years to complete, but one of them has been going on for nearly 100 years. The slowest experiment in the world started in 1927, technically 1930, and is not over yet. It was started by Australian physicist Thomas Parnell who wanted to show the surprising properties of everyday materials.
He used a highly viscous tar-like substance called pitch for the Pitch Drop Experiment. It is 100 billion times more viscous than water and two million times more viscous than honey. The strange substance appears to be solid but is actually liquid. It can even shatter like glass if hit with a hammer.
As part of the experiment, Parnell heated the pitch and poured it into a glass funnel. It was then allowed to sit and cool for three years. The experiment finally began in 1930 when he cut the bottom of the funnel to let pitch drip out slowly… really slowly.
The dripping is painfully and agonisingly slow. It is so slow that only nine drops have fallen out of the funnel since it all started. Neither Parnell nor Professor John Mainstone, the second scientist to take care of the experiment, ever got to see a drop fall.
Even though the funnel was cut and set in 1930, the first drop didn’t fall until 1938. The drops have largely had a difference of eight to nine years between them.
However, the last drop to fall was in April 2014, 14 years after the eighth drop fell in 2000. The next drop is expected to come down soon. The rate of flow of the pitch varies according to changes in temperatures.
A Guinness World record
The experiment is also a part of the Guinness World Records. Inching towards the 100-year mark, it is listed as the world’s longest-running laboratory experiment.
If this is something that excites you, then you can visit the Parnell Building at the University of Queensland, Australia to watch the experiment. It is also available to be streamed live. The university says 483 people saw the ninth drop descend in 2014 via live webcam.