Bubbles in Beijing: The story behind the Watercube Aquatics Centre

Exploring the mathematics that inspired the design of the stunning Watercube for the Beijing Olympics; the history of efficient packing in 2 and 3 dimensions

The Watercube aquatics centre made a spectacular impression at the
Beijing Olympics, resembling at night a glowing cube made of blue
bubbles. The story of the Watercube's design can be told as the mathematical history of efficient packing in 2 and 3 dimensions. Lord Kelvin studied soap bubbles and defined the 'Kelvin problem' in 1887: how can space be partitioned into cells of equal volume with the least area of surface between them, i.e., what is the most efficient soap bubble foam? Kelvin's solution consisted of tetrakaidecahedra (with 8 hexagonal and 6 square faces); a model makes it easier for one to be convinced that such shapes do fit together to fill space. For more than 100 years, Kelvin's solution was believed to be the most efficient foam structure. Then, in 1993, two physicists in Dublin, Denis Weaire and Robert Phelan, used computer-based search to, surprisingly, identify a more efficient structure. This uses two kinds of irregular polyhedral cells, and models are even more necessary to enable one to see how they squeeze up to one another to fill space. Ten years later, a team of architects and structural engineers were looking for a design idea for the Olympic Aquatics Centre which would portray the theme of water and also symbolise some Chinese ideal in cultural terms. Make the building square and you have the Chinese ideal of regulated harmony. Arup's designers already knew about using bubbles to form a structural cage for a building; they discovered that the Weaire–Phelan structure could be used as a basis for a structural frame for a cuboidal building, and present an exterior surface which appears organic and 'random' whilst actually being a repeating pattern. A foam structure has many other desirable properties and constructional advantages for architecture. The story is not over yet: Anthony Gormley may well realise his idea for a sculpture of a man, based on the same structure, for the Dublin Docklands.

Register to tell a friend about this lecture.

Comments

If you would like to comment about this lecture, please register here.

©2003-2006 Niminim Limited. Created by

Any ad revenue is entirely reinvested into the Lecture List's operating fund