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“It’s literally slower than watching Australia drift north”: a laboratory experiment that will survive us all | Research


Ohon Friday afternoon in April 1979, John Mainston, a professor of physics at the university Queensland, called his wife home. He told her he would not return that evening. For the past 18 years, Mainstone has cared about a step-by-step experiment, a long demonstration of extreme resin viscosity. For the first time since August 1970, the field was about to dig out of its funnel, and Mainston did not want to miss it.

Pelka is a resin – a viscoelastic substance derived from petroleum or coal tar, which is used in bitumen and for waterproofing. Which is ironic, because, no matter how hard it may seem, the resin is smooth: at least, that’s when you put it in a funnel, the sloping sides of which create a pressure gradient.

Mainston hasn’t slept all Friday. He continued to watch on Saturday, eventually calling his wife to tell her he would also not be home tonight. However, a ball of (literally) pitch-black liquid hung on the thread from the bottom of her funnel. On Sunday night, exhausted by the vigil, he went home. By the time he returned to work Monday morning, the resin had fallen into his glass.

Professor John Mainston with the eighth drop, which was formed in 1990
Professor John Mainston with the eighth drop, which was formed in 1990. Photo: University of Queensland

The resin drop experiment was first staged by Mainstone predecessor Thomas Parnell in 1927. Parnell heated and liquefied the resin, poured it into an airtight funnel and placed over the glass in a large jar. In 1930, he cut off the stem of the funnel – and waited.

Nearly a century later, the original experiment – which became the longest-running laboratory experiment in the world – stands in the foyer of the physics building in the Grand Court. The jar is mounted inside a protective plastic cube with an analog Casio desktop clock that watches every moment students and staff wander past. The funnel is held at a height by a brass tripod; at the bottom over an empty glass hovers a shiny black ball of resin.

It was Mainston, conducting an experiment in 1961, drew public attention to the fall in height. He was also the teacher of his third and current custodian, Professor Andrew White, who supervised him after Mainston’s death in 2013. Like Parnell, Mainston died without seeing a single drop that fell. “I do not take John’s place at all,” White insists. “He was the heart and soul of it.”

The dedication of Mainston was legendary. In 2005, he and (posthumously) Parnell were awarded Schnobel Prize – a satirical award, which celebrates secret and trivial achievements in scientific research. The Schnobel Prize is aimed at honoring work that makes people laugh, but also makes them think.

An experiment in falling pitch takes place in the building of the University of Queensland Physics
The experiment to drop the pitch of the sound is being conducted in the physics building of the University of Queensland, which is named after Thomas Parnell. Photo: David Kelly / The Guardian

Author Nick Earls first encountered the experiment as a medical student at UQ in the early 1980s, later writing about it in his novel Perfect Skin. “It was a demonstration that not everything is necessarily as it seems,” he says. “It simply came to our notice then. It’s just 230 billion times more viscous than water, and it flows, albeit very slowly. “

How slow? “Much slower than grass grows, much slower than paint dries,” says White, mockingly offended by such banal comparisons (and the assumption that this may be a rather boring experiment). “We speak more than 10 times slower than the drift of continents!”

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He draws my attention to the connection of the four tiles on the floor. “These tiles are moving north at a rate of 68 millimeters per year because Australia is moving north at a rate of 68 millimeters per year. It is one of the fastest continents in terms of continental drift. At least the falling heights are moving 10 times slower than that! So it’s literally slower than watching Australia drift north and people go live online to watch it. What I find really exciting. ”

This is true. It sweats more than 35,000 people in 160 countries 10th drop resin. They are still waiting. Since Parnell cut off the funnel stem in 1930, only nine drops have fallen: in December 1938, February 1947, April 1954, May 1962, August 1970, April 1979, July 1988 (when it became a popular exhibit in the Brisbane generation). Expo 1988), November 2000 and April 2014

After the sixth fall in 1979
After the sixth fall in 1979. Photo: University of Queensland

White prefers to call falling heights a demonstration rather than an experiment, as it has never been controlled and thus exposed to environmental fluctuations. For the first 30 years he sat in a cool dark closet. Mainstone exhibited it, and the field maintained an average of one drop every eight years, until in the 1980s a physics building (named after Parnell) was air-conditioned, blowing it out every 13 years or so.

Sometimes I forgot about the sensitivity of sound to environmental conditions. “At one point, someone replaced the fluorescent lamps above the display, which were very cool, with the halogen ones, which were very hot,” White nods. “No one asked anyone to change, it was done and I realized that the step, which is usually room temperature, sits at 60 degrees. About 120 halogens, so it flowed like a tap.

And yet, to this day no one has seen the drop fall. Not at the Expo (White: “Four or five people watched, it was a hot day, I think they went out for five minutes to treat themselves”), even though the live broadcast was first set up at the Millennium Event in 2000. Mainston at the time was watching from London. On this occasion a classic Brisbane the thunderstorm disrupted the power supply by turning off the lights and the camera.

Since the start of the experiment in 1930, nine tonne differences have fallen
Since the start of the experiment in 1930, nine tonne differences have fallen. Photo: David Kelly / The Guardian

Mainston died of a stroke in 2013. As a result of a hard turn, the last drop fell in April 2014, a few months after his death. Except that technically he didn’t fall. It seemed to pour into eight drops, which had already fallen and hardened in a small glass that sat under the funnel in the pot, without coming off. Reluctantly White changed the glass, being able to find an old model of imperial measurements to match the original.

Since then, the glass has been in place – clean, empty, not yet blackened by a single drop of mucus. The light is replaced by LEDs. “We had a very new beginning,” White says. “And so when someone asks me if he will fall, I can honestly say I have no idea. Because conditions have changed, as for most of the last 95 years. It’s never been permanent. “

Just a few meters below the experiment with falling pitch is a basement dedicated to quantum technology. There, White says, the lab produces light pulses a hundred million billionths of a second long. And here we are, he says proudly, “we have something happening every 10-20 years! It really reflects the different time scales of the physical world around us. ”

He looks at the funnel. There’s still quite a lot of sound. The experiment, he says, will outlive us all. “Quantum mechanics is as far away as you can get from pieces of coal that have been heated and slowly poured out of a glass tube as you can get,” he says. “I’m glad we have a new glass that will be good for another 100 years or so. After two or three goalkeepers, what to do next will be their problem. “

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