World's longest-running experiment almost 100 years old

Summary

Did you know the world's longest-running experiment is sitting behind glass outside a lecture theatre at the University of Queensland? The pitch drop experiment demonstrates the fluidity and extreme viscosity of pitch, a tar derivative that's the world's thickest known fluid. Despite running for almost 100 years, no-one has ever seen the pitch drop, due to a series of unlucky events. 🎤: Stephen Clarke #ABCNewsQld Note

Description from ABC News (Australia).