Sunday, July 10, 2005

NPR : Deep Sea Sponges Are Master Builders in Glass

"Sponges may conjure visions of the soft and squishy, but some of those living deep beneath the sea build complex glass structures that are marvels of engineering.

The deep-sea sponge Venus' Flower Basket constructs a glass building that houses a pair of mating shrimp. Courtesy of Lucent Technologies/Bell Labs

The sponge, from the genus Euplectella, uses a host of tricks for turning its brittle, primarily glass skeleton into strong structures, researchers report in the current issue of the journal Science. In fact, scientists are looking to the sponge for new ideas in materials science and engineering.

The remarkable design of Venus' Flower Basket contains core construction strategies used in civil and mechanical engineering, and at a scale 1,000 times smaller. Courtesy of Joanna Aizenberg (structure compared with the Swiss Tower in London, the Hotel De Las Artes in Barcelona, and a fragment of the Eiffel Tower in Paris.)

The sponge first builds strong microscopic fibers by gluing together thin layers of glass. Then it gathers these laminated fibers together for even more strength. It's like a bundle of sticks tied together -- much harder to break than a single twig. The bundles are arranged in a grid that gets embedded into glass cement, so it becomes like reinforced concrete.

People use these kinds of techniques to build structures such as skyscrapers. But Joanna Aizenberg of Bell Laboratories says what's amazing is that the sponge grows its lattice -- and its glasswork doesn't require the kind of red-hot furnace that human glass makers need.

'I cannot imagine how a structure of this sophistication can be produced,' says Aizenberg, the study's lead author."

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