The world’s longest-running laboratory experiment is now live streaming

At the University of Queensland, there is an exhibit that includes long run Laboratory experiments in the world. This has been going on for so long that two of its patrons have died before seeing any results.

The experiment was started in 1927 by Thomas Parnell, the university’s first professor of physics. For the purpose of demonstrating highly viscous materials, Parnell took the pitch-residue distillation of coal tar -Heated it, placed it in a sealed glass funnel, and then waited three years for it to settle into the shape of the container. It might seem like a long time to wait for an experiment to begin, but given the planned length of the demonstration, it was only a long blink.

In 1930, Parnell cut the stem of the funnel, allowing the highly viscous liquid to slowly flow out the bottom. Since then the experiment has been running incredibly slowly. Eight years after the experiment began, the first drop fell, and the next time five more drops fell. 40 years, This experiment has been going on for almost 100 years now, and has been under many different patrons. Parnell and his successor Professor John Mainstone both died without seeing the decline for themselves, Professor Andrew White being the current patron.

But now the experiment is under constant monitoring of a webcam, which means anyone can watch the next experiment. The last decline (unless there is another decline) occurred in 2014, seen here in massively bullish footage.

So, can the experiment tell us anything interesting?

Despite the experiment being less than ideally controlled (it is subject to room temperature fluctuations, and the internal diameter of the stem cannot be measured accurately without risk of damaging the experiment) it did have a few surprises for us. .

By taking into account several factors, it is possible to make a reasonable estimate of how sticky a pitch is.

“Then the viscosity of the pitch is calculated as q = (2.3 +0.5) x 108 pass, which is much larger than that of common liquids,” a paper Explain the experiment. “The viscosity of water at 20°C is 1.0 x 10-3 Near. However, it should be noted that (ignoring superfluidity) this is close to the geometric mean of the range of values ​​that physicists consider – Earth’s effective viscosity is of the order of 10.20 PA S.”

This does not match previous predictions at all.

“The viscosity results from the pitch drop experiment do not match well with predictions based on [previous] The measurement allows for even the enormous variation of viscosity with temperature and the unknown temperature history of the experiment.” team writes, “The possible explanation lies in the different viscosities of different samples of pitch – these may contain unequal proportions of trapped volatile hydrocarbons and this will affect the viscosity.”

if you want You can watch the experiment live, Currently, a very large blob is forming – but we wouldn’t recommend looking at it for too long as the next drop is expected to occur sometime in 2020, and there’s still quite a decade left.

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