World’s longest lab experiment still going 85 years later
Video screenshot by Bonnie Cha/CNET)
In 1927, Professor Thomas Parnell of the University of Queensland in Australia set out to teach his students a lesson, and that lesson is still going on today and has at least another 100 years to go.
The physics professor wanted to demonstrate to his pupils that solid material could have viscous properties, so he used tar pitch, a derivative of coal once used to waterproof boats, in an experiment to prove his point.
At room temperature, pitch appears to be solid and can even shatter if hit with a hammer, but despite its look and feel, pitch can also flow at room temperature–just really, really slowly.
To conduct the Pitch Drop Experiment, Parnell melted some pitch into a glass funnel with a sealed stem and allowed it to settle for three years. In 1930, the funnel was unsealed, clearing the way for the pitch to flow freely, but it sure did take its sweet time.
Eight years went by before the first drop of pitch hit the beaker below, and it was another nine years before the second drop hit. Parnell passed away in September 1948, but a third drop was recorded in 1954, before the Pitch Drop Experiment was stored away in a cupboard.