"Smart materials" are already a big hit in sports. In baseball, for instance, new aluminum bats can now quiet the "bees" a player feels when hitting a ball off the handle. Likewise, smart skis can damp vibrations as needed. The "active" part of these sporting goods is a credit-card-sized wafer that uses quirky but well-studied materials called piezoelectrics. These compounds convert mechanical stresses, such as vibrations, into an electric signal (which can be harmlessly shunted), or, conversely, change shape or size in response to electricity.

But what if researchers could find ways to make the entire product active, rather than just a discrete embedded device? That could mean smart helicopter rotors or airplane wings that twist on command, changing shapes to reduce vibrations and noise. Key to that is finding active materials that are highly responsive and yet tough enough to form structural parts.