In what is surely one of the most gripping experiments currently underway, scientists in Australia have been watching a beaker containing pitch, a tar derivative, since 1927. The researchers' goal in the planet's longest-running experiment—which holds a place in the Guinness Book of World Records—is to show that solids can flow like liquids. And flow this solid did, with the ninth drop finally occurring at the University of Queensland over the weekend, Phys.org reports. As New Scientist reports, drop No. 9 hasn't actually detached from the pitch above it, but has collided with the eighth drop on the beaker's bottom.
Between 1930 and 1988, one drop fell an average of every eight years, says Professor Andrew White. But "the 2000 (eighth) and 2014 (ninth) drop each took about 13 years to fall, and each collided into the decades-old pile of drops in the beaker before it could break away from the funnel," White says, explaining that the eighth drop didn't actually break free until this year. This marks the first time anyone's actually seen a drop occur, thanks to three webcams that are trained on the experiment and streaming a live feed. The scientist who spent 52 years hoping to see one never managed to do so, though there were near misses, including a very-ill-timed webcam outage in 2000. He died in August. (A similar experiment underway in Dublin since 1944 finally caught a drop on camera last year.)