The Pitch Drop Experiment, initiated in 1927 by Australian Professor Thomas Parnell, is recognized by Guinness World Records as the world’s longest-running scientific project, demonstrating the viscosity of pitch, a viscoelastic fluid.
Each drop of pitch takes nearly a decade to fall, with the current rate estimated to produce a drop every 13 years due to environmental factors and temperature changes.
No one has ever witnessed a pitch drop fall in real-time; the last drop occurred in 2014, and the next is expected between 2020 and 2030.
The experiment is broadcast live online 24/7, attracting over 35,000 viewers from 160 countries, with some individuals watching for hundreds of hours in hopes of witnessing the elusive event.
Similar long-term scientific experiments include the Framingham Heart Study, ongoing since 1948, which has significantly contributed to understanding cardiovascular disease.
Other notable experiments include the Vesuvius Observatory, monitoring Mount Vesuvius since 1841, and the Old Rotation Experiment at Auburn University, demonstrating sustainable agricultural practices since 1896.