Transcript: Breaking Point: Testing Tensile Strength

DAVID POGUE Kevlar is clearly some tough stuff.

Whoa!

But how does it work?

TUCKER NORTON If you were to zoom down at about 100-million times...

DAVID POGUE Well, we have a really nice camera, can you zoom down 100-million times?

Kevlar is a polymer, a long repeating chain of atoms, in this case, carbon, hydrogen, oxygen and nitrogen. Each chain is like a stiff piece of spaghetti. Gathered into bundles, the stiff chains create a thread-like fiber that has a hard surface, extremely high tensile strength and enough toughness to absorb the impact of a bullet.

Stopping a round is impressive, but there are other threats out there. How does Kevlar stand up to a knife or an ice pick?

Don't try this at home.

I'm not going to pay a lot for this muffler!

I said, "Caesar, on the side."

Twenty cents a text message? Are you nuts?

That's amazing. How can it do that?

TUCKER NORTON Well, it does it because of the tight weave and because of the strength and durability of Kevlar. The tight weave prevents the spike from getting all the way through, from working its way through. And the strength of that Kevlar actually helps blunt that tip and maybe even bend that tip if you are strong enough.

DAVID POGUE Since it was invented, Kevlar has been used in all kinds of products, from tires to parachutes and even cables. And that gives me an idea.

Tucker, I've got this friend. Um he's got a fleet of nuclear aircraft carriers and, they have these steel cables, a lot like this, that are designed to stop aircraft that are landing, 130 or 150 miles an hour. How does the strength of one of these cables compare with a steel cable?

TUCKER NORTON Well, we'd expect the strength of this, the tensile strength, to be actually equal or better than something like the steel cable.

DAVID POGUE And, it's lighter and it's less dangerous if it snaps?

TUCKER NORTON That's right.

DAVID POGUE Tucker doesn't think that anyone has ever tested Kevlar arresting cables, but I think I may be on to something.

This, this could be a sales opportunity for you.

TUCKER NORTON We appreciate that, thank you very much, David.

DAVID POGUE I'll look for my commission.

With its tensile strength greater than steel, extreme flexibility and heat resistance, in a package that weighs one-fifth as much as steel, Kevlar could, one day, be a replacement for steel cables.