(1 Shakespeare, 1642 ).
If you sit and watch the Foucault pendulum for an hour, you will "see" that the plane of the swing of the iron ball slowly shifts anti-clockwise by about 8.4 degrees per hour. But your perception is being tricked. The Pendulum stays in the same plane, and the building actually rotates "under the Foucault Pendulum! This is the amazing thing about the Foucault Pendulum. If you lived underground, or on a planet with thick cloud cover so that you had no direct view of the sky, the Foucault Pendulum is the only easy way to prove that your planet rotated. The Foucault Pendulum proves that the Earth rotates!
The Foucault Pendulum (support + wire + iron ball) is attached to the top of the central dome of the Queen Victoria Building (QVB) . The QVB is attached to the Planet Earth, which rotates on its own axis about once every 24 hours. The Earth also goes around the Sun, once every year. The Sun, in turn, goes around the centre of our galaxy, The Milky Way, once every 300 million years. These are all local motions.
The Foucault Pendulum somehow ignores all these local motions! The Foucault Pendulum somehow stays lined up in its original orientation with the Rest of The Universe.
Imagine that the Foucault Pendulum is set up at the Geographic (2) South (or North) Pole (this is the simplest case - the motions are a little more complicated anywhere away from the Poles). Imagine that you, very carefully, release the ball. Imagine that the air resistance is so low that the ball will swing for days. The ball will keep on swinging in the same plane in which you first launched it. The Pendulum will swing in a plane that is fixed relative to the distant stars (or The Rest Of The Universe), but the Earth will rotate "under" the Pendulum. So over a single 24-hour day, the Foucault Pendulum will "appear" to gradually sweep out a 360 degree circle.
(2 The operation of a classical Foucault Pendulum has nothing to do with the magnetic field of the Earth. The Geographic North and South Poles of the Earth are the Poles about which the Earth appears to rotate. These Poles are not "fixed", but actually perform a very slow wobble, or precession ).
How does the Foucault Pendulum "know" to ignore local motions (3), and line itself up with the distant stars? Some very reputable physicists say that we really don't know.
(3 I wonder if watchmakers find that "Grandperson Clocks" (the ones with a pendulum inside) wear their bearings differently on each side of the equator, as the pendulums try to sweep out a 360 degree circle? )
Perhaps it's a case of Newton's First Law of Motion:- "A body will try to keep on doing whatever it's doing, unless acted upon by an external force." So a body that is motionless will not move, unless an external force tries to push it. And a body that is moving will keep on moving, unless an external force tries to stop it.
This desire of a body to keep on doing whatever it's doing, is called inertia. Nobody really understands what inertia is. The traditional explanations involve some circular reasoning. The reasoning goes like this. A body will keep on doing whatever it's doing is because it has inertia. And inertia is the tendency of a body to keep on doing whatever it's doing. But why does it keep on doing what it's doing? Because it has inertia. But what is inertia? The tendency of a body to keep on doing whatever it's doing. And so on.
At the North and South Poles, the Foucault Pendulum will take 24 hours to sweep out a complete 360 degree circle. This motion is anticlockwise in the Southern Hemisphere, and clockwise in the Northern Hemisphere. At the Equator, it will take an infinite time to sweep out a complete 360 degree circle. At the latitude of Sydney, it will take about 43 hours to sweep out a complete 360 degree circle (4). This works out to about 8.4 degrees every hour, or about 84 degrees in 10 hours. If you sit and watch the Pendulum, you will soon see a change.
(4 This is the equation tells you how long the ball will take to describe a complete 360 degree circle :-
Time = 23 hours and 56 minutes / sine (local latitude).
The time of 23 hours and 56 minutes is the time taken for the Earth to do one complete revolution. The time of 24 hours is the time taken for the Earth to rotate so that the same point is directly under the Sun. These times would be the same if the Earth did not orbit around the Sun. But the Earth does orbit the Sun, and the extra 4 minutes is the time taken for the extra rotation needed for a given point on the Earth to once again be directly under the Sun.
The time taken for a complete 360 degree circle is one day at the Geographic Poles, 30.6 hours in London, 2 days at New Orleans, 4 days in Manila, and 40 days on Howland Island in the Pacific ).
In fact, you could draw on the ground a 43-hour clockface, and read the time off it!
In 1848 Léon Foucault was setting up a long, skinny metal rod in his lathe. He "twanged" it, and the end of the piece of metal proceeded to go up-and-down. If you treat the chuck of the lathe like a clock, the end vibrated from 12 o'clock down to 6 o'clock, and back to 12 o'clock, and so on. He slowly rotated the chuck by 90 degrees (to the 3 o'clock position). But the end of the metal rod steadfastly vibrated back-and-forth between 12 and 6 o'clock!
This set Léon Foucault thinking. He set up a small pendulum in his drill press. He set the pendulum oscillating, and then started the drill press spinning. Once again, the pendulum kept swinging in its original plane, and ignored the fact that its mounting point was rotating.
He then constructed a 2 metre-long pendulum with a 5 kilogram ball in his workshop in his cellar. Before the amplitude of the swing died away totally, he saw that the weight on the end of the pendulum appeared to rotate clockwise (5). Now that he was convinced of the principle, he built a second pendulum with an 11-metre wire in the Paris Observatory, and it too rotated clockwise.
(5 His pendulum rotated clockwise, because he was in the Northern hemisphere. Had he done his work in the Southern hemisphere, his pendulum would have rotated anticlockwise ).
He was asked to construct something "big" for the 1850 Paris Exhibition, and he constructed a 67-metre-tall Foucault Pendulum in the Pantheon - a Parisian church, also known as the church of Saint Geneviéve. He went to a great deal of trouble to make sure that the wire was perfectly symmetrical in its metallurgy. He used a 28 kilogram cannon ball. A stylus (a long skinny rod with a point on the end) was attached under the ball, and sand was scattered under the potential path of the ball, so that the stylus would cut a trace in the sand.
The ball was pulled to one side, and held in place with a string. With much ceremony, the string was set alight, and the stylus on the bottom of the ball began to mark out a beautiful, straight line in the sand. Within a few minutes, the arc of the pendulum had begun to swing a little clockwise - and the narrow, straight line in the sand had widened to look like a twin-bladed propeller. The experiment was a success! He showed that the Earth rotated "under" his pendulum.
So it was possible, way back in 1850, to set up an experiment inside a room which had no view of the outside world, and prove that the Earth rotated! (6)
(6 Galileo got into trouble for his statements about the Earth going around the Sun. But if he had thought of building a Pendulum, it would have been a powerful argument in his favour. The Foucault Pendulum would also be useful for an intelligent race who lived underground, to try to work out if their home planet rotated !)
The next year, Foucault repeated his Pendulum experiment with a massive, spinning weight. He showed that this weight, just like his Pendulum, ignored local effects and lined itself up with the distant stars. He had invented the gyroscope!
In 1955, Mr. H. Luns, the Dutch Foreign Minister, presented to the United Nations a Foucault Pendulum for installation in the entrance hall of the United Nations building in New York.
In October 1995, the original Foucault Pendulum was reinstalled in the Pantheon, using the original lead-coated brass ball.
(7 According to those who have made a Foucault Pendulum, if you are careful, you should be able to keep the time for a complete 360 degree rotation to within 15% of the predicted value. At the moment, our Foucault Pendulum takes about 48 hours to rotate through 360 degrees, instead of 43 hours - an error of about 12%! Sometimes, you are lucky !)
3.1 The BALL SUBSYSTEM is currently operational. The support bracket is mounted some 20 metres above you. The support bracket incorporates a brass rod, which is joined onto the wire. The wire is piano wire, and holds up the ball. The ball itself is made from iron, and weighs about 5 kilograms. We chrome-plated it to make it look pretty. The combination of support bracket, wire and ball make up a Pendulum that swings in a large void. Unfortunately, the wind currents in this central void tend to kick the ball around. (See BALL SUBSYSTEM, Section 4, for more details.)
3.2 The MAGNETIC SUCKER SUBSYSTEM is currently working. It has always been the most unreliable part of the whole Foucault Pendulum. However, since Peter Maul has rebuilt the Magnetic Sucker, and since he has adjusted its height and power, it has become more reliable. We need a magnetic sucker because, left to its own devices, the swing of the pendulum will shrink to just a few centimetres after only a few hours. The purpose of the MAGNETIC SUCKER SUBSYSTEM is to give a little, well-timed, magnetic "kick" to the iron ball, so its swing will not rapidly fade away. (See MAGNETIC SUCKER SUBSYSTEM, Section 5, for more details).
3.3 The BOX SUBSYSTEM is currently operational. It has been very reliable. The main purpose of the box is to shield the Pendulum from wind currents. Its other job is to catch the heavy iron ball, in case the wire breaks. It's made from polycarbonate and aluminium. Absolutely no computer analysis has been carried out to see if it will shield the Pendulum from larger-than-normal wind currents (these wind currents may very well loop over the walls of the box and dive down to kick the ball). However, it appears to have successfully shielded the ball during August, which is traditionally the windiest month of the year. (See BOX SUBSYSTEM, Section 6, for more details).
3.4 The FRAME SUBSYSTEM is also currently operational. It has also been very reliable. It's job is to provide a framework, so that we can see the action of the Pendulum from underneath, as well as from above. We believe that this is the first Foucault Pendulum in the world, which people can view from below! (See FRAME SUBSYSTEM, Section 7, for more details).
The support system is best viewed with binoculars (sorry about that). The beautiful stained glass dome that you see above you is some 20 metres inside the beautiful copper dome, that you can see from the outside. The stained glass dome is made from a wrought-iron frame, with the stained glass held onto spaces in the wrought-iron frame. There is a very small access hole (about 60 millimetres in diameter) at the top of the stained glass dome.
Above this hole is a small metal rectangular bracket. A brass rod, about 3 millimetres in diameter, and about one metre long, is attached to the small metal rectangular bracket. Peter Maul designed and built this support. The piano wire runs from the bottom of the brass rod, down to the ball.
If you had to build a machine to grab onto piano wire, how would you do it? If we had clamped the wire at a single pinch point, the wire would have bent at that single point, as the ball swung back-and-forth. The stresses at that single point would have been enormous. Soon, the wire would have broken.
Our previous Foucault Pendulum grabbed the wire with a special chuck, which had a smoothly-rounded mouth. This spread the stresses in the wire, so that they were not all concentrated at a single point. However, that special chuck, called a "Charron Chuck", eroded and wore out.
So this time, we decided to use a brass rod. All the bending happens in the brass rod, and the wire is virtually straight. For safety, there is a special system to catch the brass rod, if it should break. However, it is vastly over-engineered to give a considerable safety margin. All nuts in the support system have been coated with a "locking compound", so that they will not come loose.
The wire is ordinary commercial piano wire. It came on a 500 foot (150 metre) roll. We simply unrolled it, and installed it. But some builders of previous Foucault Pendulums have gone to enormous trouble to get wire which had never been coiled. (8) In those cases, the wire was lashed to a straight rod (up to 50 metres long!) and transported to the site of the Pendulum.
(8 After all, the stresses in a wire which was straight, and then coiled, and then straightened again, are different from the stresses in a wire which has never been coiled. However, we didn't think that getting hold of never-coiled wire would be worth the trouble ).
Even today, guitar players can buy special straight strings called Nashville Straights. They come in a long, skinny box - so from the time they are made in the factory, to when they are first used, they have always been kept straight! Some guitarists think they get a different, and better, sound from these strings that have never been coiled.
The iron ball weighs about 5 kilograms. It was turned out of a solid block of steel by the Physics Department Workshop. The ball (or weight) in a Foucault Pendulum can be made out of any material - the denser the better. The more dense that it is, the less effect that air resistance has on it.
Some Foucault Pendulums are started up by hand, and then quickly wind down. In our case, we chose to keep the ball swinging automatically. This was so we did not have to get a human to venture out into the "void" to start it up every few hours. The easiest way to do this was with a simple Magnetic Sucker - but this meant that the ball had to be made of iron. The iron ball has a small threaded cylinder screwed into it. Inside the small threaded cylinder is a tapered chuck, which grips the piano wire.
The little tin men/aluminium rectangles were made by the Physics Department Workshop. The cylinders came from long bars of aluminium, which were chopped to size, and then smoothed off by blasting them with tiny glass balls. We chrome-painted the cylinders to make them look pretty.
The hinges are commercial hinges, some of which were "sticky". So with each hinge, the Physics Workshop pushed out the pin, drilled the hole a little bigger, re-installed and lubricated the hinge, and glued one side of the hinge onto the top of the aluminium cylinder. They bent a small rectangle of aluminium, and glued the smaller end onto the other side of the hinge.
The surfaces of the rectangles are available for putting the name or face of anyone you wish. Once a day, they will be knocked over by the Iron Ball. Please contact me to arrange the installation of the name or face.
However, there is still a Major Problem with the location of the QVB, which affects the Support System. The QVB is directly above a subway. From time to time, if you are on the lowest level of the QVB, you can feel the floor shake and rumble. This is because of the trains running underneath. The Support System is mounted right in the centre of the building. This seems to act as a point where various vibrations come to a focus.
This might explain what we have seen. In one of our early tests, we had the ball hanging perfectly stationary. Suddenly, Peter Maul saw the ball jump, and then start swinging. From a standing start, the ball began to oscillate in an egg-shaped (elliptical) orbit, about 5 cm by 7 cm, with the long part of the orbit being in the East-West axis of the QVB. So this means that at various times, extra motions are being "injected" into what we want to be a smooth straight-line swing. This can cause problems with the Magnetic Sucker.
These same forces will soon reduce the size of the back-and-forth motion of the Foucault Pendulum. The MAGNETIC SUCKER gives a little, regular, carefully-timed, magnetic "pull-on" to the iron ball, so that it will keep on swinging indefinitely.
There are two parts to the MAGNETIC SUCKER - the big coil (which sucks), and the little coil (which senses).
The purpose of the big coil of dark copper wire about 50 cm in diameter, is to pull the iron ball towards the centre. The sensing coil (the small red-brown wire coil, about 10 cm in diameter) senses the magnetism of the iron ball, and switches off the MAGNETIC SUCKER once the iron ball has passed over it. An electronic timer is then activated. It waits until the iron ball gets near the end of its swing, and then, the electronic timer switches the MAGNETIC SUCKER on again.
If you look at the Southern end of the frame, where it rests on the edge of the void, you should be able to see two boxes between the arms of the frame. The right-hand box holds the control circuitry . The left-hand box, with a red light glowing on the front, holds the power supply for the MAGNETIC SUCKER. The single red light, on the extreme left of the left-hand box, means that the power to the box is on. After about 3-or-so swings, another red light switches on, to the right of the first red light. This second red light means that power (4 amps at about 24 volts = about 100 watts) is being sent to the big coil of the MAGNETIC SUCKER. This red light will then switch off as the IRON BALL passes over the sensing coil.
The big copper coil actually slightly magnetises the iron ball. So as the magnetised IRON BALL moves, it carries magnetic lines of force with it. As it passes over the sensing coil, these magnetic lines of force are "cut" by the sensing coil. This induces a current in the sensing coil. Because the wire in the sensing coil has a resistance, this current causes a slow voltage "spike" to appear in the wire. This spike then is detected by special electronic circuitry in the control box. The spike is about 1 Volt high, and the new improved circuitry that Peter Maul built triggers when it senses a spike bigger than 0.1 Volts. So there is a considerable safety margin.
However, there are two potential problems here - eccentricity, and failure of the sensing coil to fire. Let's look at eccentricity first. Everything is fine if the centre of the swing is lined up exactly with the centre of the MAGNETIC SUCKING coil. But if the centre of the swing is NOT lined up exactly with the centre of the MAGNETIC SUCKING coil, the MAGNETIC SUCKING coil will give an off-centre kick to the iron ball. This will start the iron ball swinging in a side-to-side elliptical (or egg-shaped) motion. This motion could be strong enough to counteract the slight anticlockwise motion of the ball, due to the Earth spinning "under" it (9). So the MAGNETIC SUCKER should have radial symmetry to minimise the possibility of an elliptical motion.
(9 The physics of the situation is that the "plane of oscillation" will rotate (or precess) in the direction in which the ellipse is traced. This rate of rotation is roughly equal to the area of the ellipse. So in some cases, a Foucault can run backwards, or at least, indicate that the Earth has suddenly begun to rotate backwards! )
We took great care to line up the centre of the swing, and the centre of the MAGNETIC SUCKER. Peter Maul drilled and tapped a screw thread at the exact "South Pole" of the IRON BALL. This threaded hole will take a modified carpenter's plumb bob.
Peter stopped the ball. (This is hard to do in the daytime, with (we think) trains continually vibrating the ball, by shaking the support high up in the dome. In the daytime, we spend an hour getting the ball almost perfectly still, and then it will suddenly jump, and start moving. In the nightime, the ball seems to jump a lot less.) Prior to this, he had mounted the MAGNETIC SUCKER on a sheet of Perspex. The centre of the MAGNETIC SUCKER was marked by lines scored into the Perspex at right angles to each other. Where the lines crossed was the centre of the MAGNETIC SUCKER. Then he moved the MAGNETIC SUCKER around until it was directly under the plumb bob.
The other problem is the failure of the sensing coil to activate. This caused us a lot of heartbreak in the first week. The pendulum would work for about a day, or less, and then stop. We think that the trains were shaking the IRON BALL, so that it would miss the sensing coil. The sensing coil would not generate enough voltage to switch off the MAGNETIC SUCKER. This meant that the MAGNETIC SUCKER would stay on, always sucking on the IRON BALL. The size of the swing would very rapidly shrink - much faster than if the MAGNETIC SUCKER were not permanently on. Quite soon, the "kick" that the trains (we think) had given the IRON BALL would die away, so the IRON BALL would be swinging directly over the centre of the sensing coil. Unfortunately, it was swinging too slowly to generate enough voltage to activate the sensing coil circuitry.
We couldn't stop the trains, so Peter redesigned the sensing coil circuitry to be more sensitive, without picking up more "noise". So far, it seems to be working.
We tried to keep it as simple as possible. Part of the reason for this was that "simple" and ''useful" things often look better than "complicated" things. In 1884, the playwright, Oscar Wilde, said, in The Value of Art in Modern Life "I have found that all ugly things are made by those who strive to make something beautiful, and that all beautiful things are made by those who strive to make something useful."
The box has been built around the Foucault Pendulum for three reasons.
First , the box is supposed to stop wind currents from affecting the swing of the iron ball. The QVB has its long axis running North-South. The Foucault Pendulum is halfway along the length of the building. The QVB is open on both the West and East sides, and wind can sometimes rush in through these entrances. This wind can "kick" the swing of the ball off to one side, so that the iron ball does not pass directly over the centre of the red sensing coil. The ball is then magnetically sucked towards the main coil - not towards the centre, but a little off to one side. Once this off-centre motion has been established, it will continue - powered by the MAGNETIC SUCKER. This elliptical (or egg-shaped) motion can be so powerful, that it can overcome the relatively weak Coriolis force that tries to make the plane of the swing of the iron ball move anticlockwise.
Second , the box is there is to catch the ball in the very unlikely case that the wire breaks. The most likely place for the wire to break is right at the top, where there is the possibility of the wire bending through a sharp angle. We have bypassed this potential weak point by installing the brass rod. There is also a back-up system to catch the rod, in the unlikely event that it breaks. The box is made from bulletproof polycarbonate, as used in bulletproof windows for cars. This polycarbonate is massively over-engineered to catch a 5-kilogram iron ball falling a maximum distance of 20 centimetres.
Third , the box is transparent so that we can see the swinging ball from below. This is very important for artistic reasons. In many public areas, you will see "Works of Art". The main motivation for building this Foucault Pendulum, is to put, in a public area, a "Work of Science". It's as simple as that.
The Lexan is AR Sheet. The floor is 9.5 mm thick, while the walls are 6 mm thick. Lexan is more expensive than Perspex, but much stronger, and it resists heat much better. The total cost of the Lexan alone was $5,000!
Trying to set up this Foucault Pendulum within the Queen Victoria Building proved to be challenging, as well as very interesting. Everybody involved in the construction had to think very laterally, to build it within the constraints of the design.
The structure over the void, two floors above ground level, had be able to support, not only its own weight, but also the weight of persons having to venture out and maintain the Pendulum. The structure had to be built out of the smallest sections possible, so as not to block the view of the Pendulum. It had to be built so that viewers from almost any angle could see the Pendulum. Very importantly, the structure had to be designed so that it did not detract from the heritage surroundings it inhabited.
Ultimately, this meant that we had to use a structural-grade plastic sheeting for the base and the sides of the structure, so that the Pendulum could be viewed from the sides and from underneath. It also meant that we used aluminium girders and stainless-steel wires. The look-and-feel is fairly minimalist - just transparent sheets, and shiny silvery metal.
The initial erection began by installing scaffolding across the void - this took 2 weeks. This incorporated 4 scaffold trusses, each 7 metres long. This meant that the constructors could work safely above ground level, without worrying about falling. During this time, they installed the frame. The site co-ordination & final assemblage were provided by Adam Seager and Gill Seymour from Minsterley Pty. Ltd.
The final structure is made of only three prefabricated structures. One is a set of 6.5 metre-long "railway lines" that run North-South. The other two prefabricated structures are two short Double-Y structures, that run East-West, that are bolted to the sides of the "railway lines".
The void is 6 metres across. Luckily for us, aluminium RHSs (Rolled Hollow Sections) come in lengths 6.5 metres long. The strongest parts of the our structure run North-South. These RHSs are 200 mm high x 50 mm wide x 5 mm (wall thickness) by 6.5 metres long. There are two short side sections, 200 mm high x 50 mm wide by 3 mm (wall thickness) that are joined onto the long sections. The connection and bearing plates (which are made from 10 mm thick aluminium) are joined by 12.5 mm stainless steel bolts. Val Blazek from Shangrila Welding did the high-strength gas welding.
Rod Laing-Peach and Michael Kirkman (of KLP Design) designed the structure to use yacht rigging, so that the structure would not sag in the middle. Don Buckley (of Lamotrek Pty Ltd) was in charge of the yacht rigging. There are two main advantages of using yacht rigging - first, it is almost invisible, and second, it provides more than enough strength and stiffness for the long aluminium sections spanning the void. (The yacht rigging is best seen from below). There are 4 strands of 386-grade stainless steel wire. Each strand is 4.8 mm in diameter, and is made up of 19 wires, which are swaged at each end with a turnbuckle adjustment. The wires are tensioned to 900 kilograms. If they were over tensioned, the upper section would turn inside out like a banana!
Dennis Young and Rod Wong (of Meinhardt Pty. Limited) were in charge of the overall integration of the engineering.
8.1 IT'S A JOKE! The book has nothing to do with Jean Bernard Léon Foucault (10) (1819 - 1868), who built Foucault's Pendulum. It deals with the work of another Foucault, Michel Foucault (11) (1926 - 1984), who was a philosopher!
(10 J. B. L. Foucault was quite an experimental scientist. In 1845, he took the first photograph of the Sun. He measured the velocity of light in his laboratory using a rapidly-spinning mirror and showed that light travelled more slowly in water than in air, and invented the gyroscope. He also worked with telescope mirrors, lenses, prisms, and arc lamps. He showed that eddy currents could be generated by magnetic fields. He also showed that the brain combines two separate color images from your two eyes to make a single image ).
(11 Michel Foucault looked at the theories of order under which societies operate, and how these societies define themselves via "exclusions". So you could learn much about a society if you saw how it compared criminals and non-criminals, citizens and foreigners, etc. He wrote many books. He said, among other things, that "There are more ideas on earth than intellectuals imagine. And these ideas are more active, stronger, more resistant, more passionate than "politicians" think. We have to be there at the birth of ideas, the bursting outward of their force: not in books expressing them, but in events manifesting this force, in struggles carried on around ideas, for or against them. Ideas do not rule the world. But it is because the world has ideas . . . that it is not passively ruled by those who are its leaders or those who would like to teach it, once and for all, what it must think." )
8.2 WHAT THE BOOK IS REALLY ABOUT Foucault's Pendulum (the book) deals with the "discursive nature of knowledge". This is what "discursive" means:
Suppose some scientists are investigating a field of knowledge, which has not yet been deeply explored. They individually do experiments, think about what the experiments mean, and come up with conclusions. The scientists then get together (either in person at a conference, or via scientific journals or magazines) and discuss their conclusions. "Discursive" is an adjective relating to the noun, "discussion". In other words, some knowledge can be spread in a discursive fashion.
Discursive knowledge covers many fields of human endeavour, from scientific endeavours, to conspiracy theories (UFOs, the supposed role of the CIA in the Whitlam Government's fall, etc), to anecdotal information about where to get the best cappuccino in town (the coffee shop on the ground floor just next to the void).
This is my interpretation of what Tony Nolan told me about the book. I take full responsibility for any errors.
John Pigott , (Senior Technical Officer - Plasma Physics, University of Sydney), for offering his invaluable advice, based on years of experience.
Caroline Pegram , (Research Assistant - Science Foundation for Physics, University of Sydney), for being enthusiastic, and for caring, and for managing millions of details.
Graham Mannes , (Head of Workshop, School Of Physics, University of Sydney), for helping in so many mechanical-workshop ways, and for re-making the aluminium-cylinder-rectangles-to-be-knocked-over.
Professor Rod Cross , (Plasma Physics - University of Sydney), the original designer of this pendulum for having built an early Foucault Pendulum, many parts of which we used in this version, for having saved the necessary documentation (which made it so much easier to get going), and for being kind and helpful.
Rod Laing-Peach and Michael Kirkman (KLP Design) for enthusiastically designing the project in the first instance, and then enthusiastically working on it.
Val Blazek (Shangrila Welding) for doing a superb job of high-strength gas welding.
Adam Seager and Gill Seymour (Minsterley Pty. Ltd.) for providing the site co-ordination and final assemblage.
Don Buckley (Lamotrek Pty Ltd) for doing a great job on the yacht rigging.
Dennis Young and Rod Wong (of Meinhardt Pty. Limited) for integrating the engineering, in such a beautiful way.
Neil Murray (Queen Victoria Building) for having the vision to commission such a Work of Science.
Copyright © Karl S. Kruszelnicki 1996