1. A blob of tar, also known as pitch, has finally dropped for the ninth time in a long-running experiment at the University of Queensland in Australia.
The experiment was set up in 1927 to show that solid materials can flow like liquids (if you hit it with a hammer, pitch shatters). It’s certified by Guinness World Records as the longest-running laboratory experiment.
When the experiment was set up tar was placed in the funnel and allowed three years to settle, before the funnel stem was cut. The pitch has been falling ever since. The first drop separated from the funnel in December 1938.
2. Sadly the scientist who looked over the experiment for 50 years died last year and never saw the pitch drop himself.
John Mainstone missed the eighth drop in 2000 as he was overseas at the time, and the webcam failed. He’d previously missed it by a day in 1977, and by only five minutes in 1988 when it was on display at the World Expo in Brisbane.
Nobody else has ever seen the pitch drop in person, either. Now three webcams are permanently trained on the jar to catch its every move.
3. Seven drops fell between 1930 and 1988, roughly one every eight years.
But now the drops seem to be slowing down. Just two have been observed since then, one in 2000 and the latest earlier this month, averaging once every 13 years.
4. Here is the pitch not dropping in a timelapse from last year.
It covers the period between 28 April 2012 to 10 April 2013.
5. And here it is dropping, finally.
This timelapse covers the last year. The ninth drop joins the eighth that is still sitting at the bottom of the beaker from when it fell in 2000. For now, the latest drop is still connected with the tar above it.
6. In 2001, following the eighth drop, Mainstone commented:
Strange as it may seem to the uninitiated, there is actually some fascinating physics involved in the experiment, which some of us are hoping will continue for at least another hundred years - sympathetic custodians permitting.