Transcript: Shape Shifters: Shape-Memory Alloys and Polymers

DAVID POGUE This wire NOVA logo is made from a nickel and titanium alloy. The metal was invented in the late fifties for use in missile nose cones, but then, by accident, it was discovered to have an astonishing quality.

If I stretch out this wire and then apply a little heat, it snaps back to its original size and shape. Scientists call materials like this "shape memory alloys," or S.M.A.s.

But they might as well call them artificial muscles. That's how they're being put to work here. This jellyfish robot from Virginia Tech swims without any kind of motor. In a design inspired by real jellyfish, it's propelled by the contractions of an artificial muscle, made of metal, embedded in its silicone bell. Electric current heats the material to trigger the action. Eventually a small battery will provide the power.

The goal of this work, paid for by the Navy, is a motion-detecting buoy that's inconspicuous.

DANIEL INMAN If it looks like a jellyfish, then maybe someone will think it is a jellyfish and not bother it.

DAVID POGUE Oh, I see. So we could actually spy on the bad guys.

"Wait! Who goes there? Oh, it's just a jellyfish."

Even beyond artificial muscle, shape-shifting metals and plastics may be the shape of things to come.

Imagine if your watch could morph into your cell phone, or your family sedan could turn into a roadster.

But today, shape memory alloys are saving lives. This is a stent. It's designed to keeps an artery open. Surgeons can shrink it down for insertion and then the heat of the body, like this hot water, expands it into place. Smart: just one example of how new materials have revolutionized the world of medicine.