The Latest on Long-Running Experiments
We are happy to report that three of the worlds longest-running scientific experiments are indeed still running.
It has been a number of years since anyone checked on all three. With assistance from scientists in several nations, we have managed to do so.
Background on these Experiments
In 1984, the European Journal
of Physics published three remarkable reports, each describing a different
experiment that had been continuing for decades. The youngest -- the pitch
drop viscosity experiment at the University of Queensland in Brisbane --
had been started in 1927. The oldest -- the now-and-then-famous Oxford electric
bell at Oxford University, was begun in 1840. The third experiment, the
Beverly clock at the University of Otago in Dunedin, was commenced in 1864.
The Pitch Drop Experiment
In Brisbane, pitch is dropping.
As described by R. Edgeworth, B.J. Dalton, and T. Parnell in their
Here is the record as it was presented in 1984:
In the foyer of the Department of Physics at the University of Queensland in Brisbane is an experiment to demonstrate, for teaching purposes, the fluidity and the very high viscosity of pitch, set up in 1927 by Professor Thomas Parnell, the first Professor of Physics there.
The pitch was warmed and poured into a glass funnel, with the bottom of the stem sealed. Three years were allowed for the pitch to consolidate, and in 1930 the sealed stem was cut. From that date the pitch has been allowed to flow out of the funnel and a record kept of the dates when the drops fell.
1930 The stem was cutA seventh drop fell during July 1988 during World Expo 88.
1938(Dec) 1st drop fell
1947(Feb) 2nd drop fell
1954(Apr) 3rd drop fell
1962(May) 4th drop fell
1970(Aug) 5th drop fell
1979(Apr) 6th drop fell
Now, in the spring of 2001, the pitch is flowing as heartily as ever. Michael
Harvey, of the physics department at the university, reports that:
At the moment the pitch drop is at the end of the most recent drop (which has not quite dropped) and so at its most interesting point in almost ten years, if you consider watching pitch flow interesting. We have a web page with some information on the experiment and a link to a live webcam of the drop. The experiment itself is in the foyer of the Parnell building, in front of two of our larger lecture theatres, so during the day the webcam also sees interested faces peering at the experiment.
The pitch drop web site: <http://www.physics.uq.edu.au/pitchdrop/pitchdrop.shtml>.
The web cam: <http://www.physics.uq.edu.au:8090/ramgen/encoder/pitchdrop.rm>
A video clip of pitch being shattered by a hammer is at <http://www.physics.uq.edu.au:8090/ramgen/pitchhit.rm>
The Oxford Electric Bell
In Oxford, a bell is ringing.
As described by A.J. Croft in his 1984 report:
In the foyer of the Clarendon Laboratory in the University of Oxford is an electric bell which has been ringing almost continually since it was bought and first displayed in 1840.... The bell is of course practically inaudible.... What the piles are made of is not known with certainty, but it is clear that the outer coating is of sulphur, and this seals in the cells and the electrolyte.... On present form the clapper seems more likely to wear out than the electro-chemical energy to be exhausted.
In 2001 the bell has still not given up the ghost. Jim Williamson of the
Oxford Physics Department reports that
"It is still there and still ringing. You can see it in the glass cabinet in the foyer of the Clarendon, on the left as you go into the Martin Wood."
The Beverly Clock
In Dunedin, a clock is ticking.
As described by L.E.S. Amon, A. Beverly, and J.N. Dodd in their 1984 report
(NOTE: although Beverly was long-deceased, Amon and Dodd, having drawn heavily
from his notebooks, decided to include him as a co-author):
Ambient temperature fluctuations expand and contract the air in an air-tight box. According to calculation (Beverly c. 1864) one can obtain more than sufficient energy to drive an efficient clock mechanism, typically a one pound weight falling one inch each day, from a volume of one cubic foot of air expanding under a 6° diurnal variation of temperature.
The photographs shown here were taken by Robin
Gledhill, the technician who these days keeps the clock running. Gledhill
The clock is beautiful. It runs on both pressure and temperature, but temperature seems to be the most important factor. The two chain wheels you can see in the photo are linked on the same axis and one drives the other in only one direction by a rachet.
And so, science marches on, however slowly.
One element common to all three experiment is that of being located in
foyers of physics departments. We would enjoy hearing from investigators
who know of other such physics foyer experiments.
(Thanks to Steve Dahms for bringing these experiments to our attention, to Don Grainger for assisting with the Oxford bell update, and to Nick Kim for assisting with the Beverly clock update.)
© Copyright 2001 Annals of Improbable Research (AIR)