The Longest Running Experiment Ever

The pitch-drop experiment was started in 1927 to measure its viscosity and it continues to this date.

Photo by Jake Blucker on Unsplash

I feel often impatient when my chemical reactions take a day worth of time to finish. I try to expedite them by adjusting various parameters of the reactions.

Recently, I googled, what’s the longest-performed experiment ever? And to my surprise, it’s too long to even imagine.

The Pitch-drop experiment at the University of Queensland holds the record of the longest-running experiment ever.

Pitch is one of the most viscous materials that humankind has ever known. It’s roughly 100 billion times more viscous than water, appearing like a brittle solid to an average eye.

But surprisingly, the pitch is not exactly a static solid matter. It acts like a fluid and flows with the pull of gravity, kinda similar to glass.

In 1927, the very first physics professor of the university, Prof. Thomas Parnell, heated a sample of the pitch. And then, he poured it into a glass funnel to let the pitch cool down to estimate the viscosity of the pitch sample.

The entire setup was kept inside a sealed stem and after 3 years, the stem of the funnel was pruned. In 1938, the first drop finally dripped and it’s just the tip of the iceberg.

The next few drops took decades to fall. On 12th April 2014, the ninth drop had fallen and it was broadcasted to an audience of 30 thousand around the world.

According to the university, the tenth drop is likely to fall in the 2020s. The experiment can be checked out live by following this link.

The surrounding temperature changes with the light in the room and seasons impart an impact on the viscosity of pitch. The range is from 30-250 billion times in comparison to water.

Prof. Parnell bagged the famous Ig Nobel Prize in 2005, a satirical award bestowed to researchers whose experiments make people laugh at first and then, make them think.

After reading about this experiment, I realized, I should be more patient. My experiments take 1 day, not 1 century to complete. I am good to go!

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