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ambience: Ocean

Imagine a thin, lightweight material that could stop a rifle bullet. I'm Jim Metzner, and this is the Pulse of the Planet. Well that super shield is still on the drawing board one of the holy grails of materials research. But scientists hope to get a clue from one of nature’s most durable creations - seashells. Benjamin Bruet is a graduate student at MIT’s Department of Material Science and Engineering. He describes one of the shells that he’s been studying.

“It’s named trochus niloticus. It’s a very pretty conical seashell that you will find on the shores of the Indian Ocean. It’s about 5-6 inches in diameter. When you take a look at the cross-section of this using a microscope, you know, you will see a structure that really looks like a brick wall.

Nacre is the hardest layer of a seashell and it provides protection from predators.

“People have been studying nacre for many years now, so you could say, well you know, what still needs to be studied? Nacre is so complex that actually it is built from the very molecular level and we couldn’t really test a material at the molecular level. And recent technologies now allow us to actually test material almost at the atomic level, at the molecular level. And that’s exactly in this area that I’m working now. Trying to understand which mechanisms happen at the molecular level.”

Part of what makes nacre such an effective protector is its ability to absorb shocks, but scientists still can’t fully explain how it does this. When they’ve figured out what makes nacre such a good shock absorber, scientists hope that this knowledge could lead to a new generation of durable materials including lightweight body armor.

Pulse of the Planet is made possible by the National Science Foundation.

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