The world’s slowest science experiment is the “pitch drop experiment” at the University of Queensland. In 1927, physics professor Thomas Parnell poured some pitch into a funnel to see how long it would take to drip out. Pitch is pretty viscous: When Parnell died in 1948, only two drops had fallen.

The experiment is still going on. The eighth drop fell on Nov. 28, 2000, allowing experimenters to calculate that the pitch has a viscosity about 100 billion times that of water.