The Pitch Drop: Science’s Slowest Experiment | Smartest Year Ever (Nov 5, 2025)

At the University of Queensland, a small glass funnel has been “dripping” since 1927. But what’s dripping isn’t water — it’s pitch, a tar-like substance so thick it takes years for a single drop to fall. Known as the Pitch Drop Experiment, it’s officially recognized by Guinness World Records as the longest-running laboratory experiment in history.

Physicist Thomas Parnell started it nearly a century ago to prove that some solids are actually liquids that flow extremely slowly. Since then, it’s been a saga of missed moments, camera failures, and scientific patience — a study in viscosity that moves at the pace of geological time.

Gordy unpacks the full story of this mesmerizing experiment that’s still running today, producing roughly one drop every decade. From Parnell’s original setup in 1927 to the moment a professor’s shaky hand accidentally triggered a long-awaited drop, this is the strangest cliffhanger in science — and one that’s still teaching us the quiet power of patience.

If you think science can’t be dramatic, wait until you meet a liquid that takes 13 years to fall.

Music thanks to Zapsplat.

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Sources:

• University of Queensland. (n.d.). The Pitch Drop Experiment. https://smp.uq.edu.au/pitch-drop-experiment
  

• Guinness World Records. (n.d.). Longest-running laboratory experiment.
  

• The Conversation. (2023). World’s longest-running experiment continues to drip.
  

• Trinity College Dublin Physics Department. (n.d.). The Pitch Drop Experiment at Trinity.
  

• Parnell, T. (1930). Original Laboratory Records, University of Queensland Archives.
  

The Tenth Watch (n.d.). Official Livestream Feed of the Queensland Pitch Drop. http://thetenthwatch.com/feed/