A giant version of my balancing beams demonstration was part of the Open Field exhibition at the Centre for Contemporary Art in Glasgow, running between 21st November 2008 and 17th January 2009.
Jonathan Sanderson made the following video showing the device in action, with some commentary from me. There's a higher-resolution version here.
The device is made of 5 lattice-girder steel sections, and is a total of 4.5 metres long. It rests upon a plinth. When the visitor operates a lever, the wooden beam rocks, and the "heavy" end is lifted up. As it starts to leave the plinth, the lighter sections overtake it. Soon the whole thing is rocking in the air.
Why leave it lying on the plinth? Initially, I had envisaged that the balancing beams would be permanently hanging, but the trouble is that they stop moving after a few minutes. Merely moving the main point of suspension doesn't set all of the sections moving again - paradoxically, the whole thing moves as a rigid piece. Each section needs to be disturbed individually. I didn't dare let the visitors handle the sections directly, but on the other hand, I didn't want the device to operate automatically with no visitor intervention. Automatic disturbance would have been tricky anyway.
For the lift-it-off-the-floor solution, I am indebted to John Macfarlane, a student on the Product Design Engineering degree course at Glasgow School of Art. The sections are weighted to hang at an angle, but on the plinth, they are necessarily horizontal. Therefore, as the whole thing is lifted up, each piece starts rocking, and the visitor gets a surprise into the bargain.
Another problem that I had to solve was that of counterbalancing the aggregate weight of the balancing beams. When the beams are in mid-air, this is easy. I could adjust the counterweight on the distal end of the wooden beam so that they slowly descend. But as soon as they make contact with the plinth, some of their weight is borne by the plinth, and they stop moving down. My solution was to have a rolling cylindrical weight inside the wooden beam. When the wooden beam is tilted with its distal end down, and the balancing beams are in the air, the rolling weight is at the distal end of the wooden beam, and adds to the fixed counterweight that is there. In this configuration, the balancing beams very slowly descend. Just as they touch the plinth, the wooden beam passes the horizontal, and the rolling weight moves down to the proximal end of the wooden beam. The balancing beams are now insufficiently counterbalanced, and so they carry on sinking until they lie flat on the plinth.
It is hugely fulfilling to see one of my ideas reach a public audience at long last, and it wouldn't have happened without certain people. Belinda Gilbert Scott conceived the exhibition and put a huge amount of work and determination into making it happen. I occupied Sarah Kenchington's workshop for weeks on end while making the exhibit, and lived in a caravan provided by Sarah and Bel while I did it (as did the other artists on the exhibition - but not all at once!). Without their initial invitation and sustained encouragement, I wouldn't have done it. Finally, Alan Kean and his gallery team at the CCA went beyond the call of duty during the installation, building the plinth and the lever mechanism, as well as providing much other help and hardware. They were tremendous - the phrase "service with a smile" could have been invented for them.