Which Is the Longest-Running Scientific Experiment?

In 1927, Professor Thomas Parnell at the University of Queensland in Brisbane, Australia, heated a sample of pitch (a derivative of tar) and poured it into a sealed funnel. After three years of settling, he cut the stem and waited for the pitch to drip. The first drop fell in 1938. As of 2024, only nine drops have fallen in 97 years, with the most recent in April 2014. The experiment demonstrates that pitch, which appears solid and can be shattered with a hammer, is actually an extremely viscous liquid — about 230 billion times more viscous than water. Remarkably, no one has ever witnessed a drop actually falling in person or on camera (the 2014 drop was captured only by webcam).